Papers for Wednesday, Jun 21 2023

In this paper, we use analytical methods to study the last stages of the double neutron star (NS) system evolution. Depending on the initial masses of the components, this evolution can occur either in the framework of the merging scenario or in the NS stripping model. The main new ingredient of this work, compared with the previous calculations, is accounting for accretion spin-up of the massive component. This effect leads to a significant decrease in the duration of the stable mass transfer of matter in the stripping mechanism. Within the framework of the Newtonian approximation, we determine the mass boundary between the merging and stripping scenarios. It is shown that this boundary weakly depends on the total mass of the system and the specific form of the NS equation of state and is determined mainly by the initial mass ratio of the components. The stripping scenario is realized at M2/M1<0.8, so it should make a large contribution to the population of close to us gravitational wave events from NS-NS coalescing binaries and accompanying short gamma-ray bursts. Nevertheless, the value obtained requires further clarification, taking into account relativistic effects, possible non-conservative mass transfer, etc.

Radio astronomy is a specialised area of astronomy that examines the radio emissions from astronomical bodies within the electromagnetic spectrum's radio range. As radio telescopes have become increasingly sensitive due to technological advancements, radio astronomers face the significant challenge of reducing the impact of human-generated radio interference. Our research delved into the impact of Global System for Mobile Communication (GSM) signals on radio astronomy data, utilising a multidimensional framework approach with a probabilistic basis. We discovered a link between the location of cell towers in the nearby towns surrounding MeerKAT and a high probability of Radio Frequency Interference (RFI). However, we found no statistically significant association between the time of day and RFI occurrence at the 68% confidence level.

Far-infrared polarized emission by means of magnetically aligned dust grains is an excellent tracer of the magnetic fields (B-fields) in the cold phase of the galactic outflows in starburst galaxies. We present a comprehensive study of the B-fields in three nearby ($3.5$-$17.2$ Mpc) starbursts (M82, NGC 253, and NGC 2146) at $5$ pc-$1.5$ kpc resolutions using publicly available $53$-$890$ $\mu$m imaging polarimetric observations with SOFIA/HAWC+, JCMT/POL-2, and ALMA. We find that the polarized spectral energy distributions (SEDs) of the full galaxies are dominated by the polarized SEDs of the outflows with dust temperatures of $T_{\rm{d,outflow}}^{\rm{PI}}\sim45$ K and emissive index of $\beta_{\rm{outflow}}^{\rm{PI}}\sim2.3$. The disks are characterized by low $T_{\rm{d,disk}}^{\rm{PI}}=[24,31]$ K and $\beta_{\rm{disk}}^{\rm{PI}}\sim1$. We show that disk- and outflow-dominated galaxies can be better distinguished by using polarized SEDs instead of total SEDs. We compute the $53$-$850$ $\mu$m polarization spectrum of the disk and outflow and find that dust models of the diffuse ISM can reproduce the fairly constant polarization spectrum of the disk, $\langle P_{\rm{disk}} \rangle=1.2\pm0.5$%. The dust models of heterogenous clouds and two temperature components are required to explain the polarization spectrum of the outflow ($2$-$4$% at $53$ $\mu$m, $\sim1$% at $850$ $\mu$m, and a minimum within $89$-$154$ $\mu$m). We conclude that the polarized dust grains in the outflow arise from a dust population with higher dust temperature and emissivities than those from the total flux. The B-fields of the outflows have maximum extensions within $89$-$214$ $\mu$m reaching heights of $\sim4$ kpc, and flatter polarized fluxes than total fluxes. The extension of the B-field permeating the circumgalactic medium increases with increasing the star formation rate.

Super-Earths span a wide range of bulk densities, indicating a diversity in interior conditions beyond that seen in the solar system. In particular, an emerging population of low-density super-Earths may be explained by volatile-rich interiors. Among these, low-density lava worlds have dayside temperatures high enough to evaporate their surfaces, providing a unique opportunity to probe their interior compositions and test for the presence of volatiles. In this work, we investigate the atmospheric observability of low-density lava worlds. We use a radiative-convective model to explore the atmospheric structures and emission spectra of these planets, focusing on three case studies with high observability metrics and sub-stellar temperatures spanning $\sim$1900-2800 K: HD 86226c, HD 3167b and 55 Cnce. Given the possibility of mixed volatile and silicate interior compositions for these planets, we consider a range of mixed volatile and rock vapor atmospheric compositions. This includes a range of volatile fractions and three volatile compositions: water-rich (100% H$_2$O), water with CO$_2$ (80% H$_2$O+20% CO$_2$), and a desiccated O-rich scenario (67% O$_2$+33%CO$_2$). We find that spectral features due to H$_2$O, CO$_2$, SiO and SiO$_2$ are present in the infrared emission spectra as either emission or absorption features, depending on dayside temperature, volatile fraction and volatile composition. We further simulate JWST secondary eclipse observations for each of the three case studies, finding that H$_2$O and/or CO$_2$ could be detected with as few as $\sim$5 eclipses. Detecting volatiles in these atmospheres would provide crucial independent evidence that volatile-rich interiors exist among the super-Earth population.

The outskirts of galaxy clusters host complex interactions between the intra-cluster and circumcluster media. During cluster evolution, ram-pressure stripped gas clumps from infalling substructures break the uniformity of the gas distribution, which may lead to observational biases at large radii. Assessing the contribution of gas clumping, however, poses observational challenges, and requires robust X-ray measurements in the background-dominated regime of cluster outskirts. The aims of this work are isolating faint gas clumps from field sources and from the diffuse emission in the Abell 1795 galaxy cluster, then probing their impact on the observed surface brightness and thermodynamic profiles. We performed imaging analysis on deep Chandra ACIS-I observations of the outskirts of Abell 1795, extending to $\sim1.5r_{200}$ with full azimuthal coverage. We built the $0.7-2.0$ keV surface brightness distribution from the adaptively binned image of the diffuse emission and looked for clumps as $>2\sigma$ outliers. Classification of the clump candidates was based on Chandra and SDSS data. Benefiting from the Chandra point source list, we extracted the thermodynamic profiles of the intra-cluster medium from the associated Suzaku XIS data out to $r_{200}$ using multiple point source and clump candidate removal approaches. We identified 24 clump candidates in the Abell 1795 field, most of which are likely associated with background objects, including AGN, galaxies, and clusters or groups of galaxies, as opposed to intrinsic gas clumps. These sources had minimal impact on the surface brightness and thermodynamic profiles of the cluster emission. After correcting for clump candidates, the measured entropy profile still deviates from a pure gravitational collapse, suggesting complex physics at play in the outskirts, including potential electron-ion non-equilibrium and non-thermal pressure support.

A large fraction of white dwarfs (WDs) have metal-polluted atmospheres, which are produced by accreting material from remnant planetary systems. The composition of the accreted debris broadly resembles that of rocky Solar System objects. Volatile-enriched debris with compositions similar to long-period comets (LPCs) is rarely observed. We attempt to reconcile this dearth of volatiles with the premise that exo-Oort clouds (XOCs) occur around a large fraction of planet-hosting stars. We estimate the comet accretion rate from an XOC analytically, adapting the 'loss cone' theory of LPC delivery in the Solar System. We investigate the dynamical evolution of an XOC during late stellar evolution. Using numerical simulations, we show that 1 to 30 per cent of XOC objects remain bound after anisotropic stellar mass loss imparting a WD natal kick of $\sim$1 km/s. We also characterize the surviving comets' distribution function. Surviving planets orbiting a WD can prevent the accretion of XOC comets by the star. A planet's 'dynamical barrier' is effective at preventing comet accretion if the energy kick imparted by the planet exceeds the comet's orbital binding energy. By modifying the loss cone theory, we calculate the amount by which a planet reduces the WD's accretion rate. We suggest that the scarcity of volatile-enriched debris in polluted WDs is caused by an unseen population of 10-100 AU scale giant planets acting as barriers to incoming LPCs. Finally, we constrain the amount of volatiles delivered to a planet in the habitable zone of an old, cool WD.

The Tip of the Red Giant Branch provides a luminous standard candle for calibrating distance ladders that reach Type Ia supernova (SN Ia) hosts. However, recent work reveals that tip measurements vary at the $\sim$ 0.1 mag level for different stellar populations and locations within a host, which may lead to inconsistencies along the distance ladder. We pursue a calibration of the tip using 11 Hubble Space Telescope fields around the maser host, NGC 4258, that is consistent with SN Ia hosts by standardizing tip measurements via their contrast ratios. We find $F814W$-band tips that exhibit a full 0.3 mag range and 0.1 mag dispersion. We do not find any correlation between HI column density and the apparent tip to 0.04 $\pm$ 0.03 mag/cm$^{-2}$. We search for a tip-contrast relation (TCR) and measure the TCR within the fields of NGC 4258 of $-0.015\pm0.008$ mag/$R$, where $R$ is the contrast ratio. This value is consistent with the TCR originally discovered in the GHOSTS sample (Wu et al. 2022) of $-0.023\pm0.005$ mag/R. Combining these measurements, we find a global TCR of $-0.021\pm0.004$ mag/R and a calibration of $M_I^{TRGB} = -4.025 \pm 0.035 - (R-4)\times0.021$ mag. We also use stellar models to simulate single age and metallicity stellar populations with [Fe/H] from $-2.0$ to $-0.7$ and ages from 3 Gyr to 12 Gyr and reconstruct the global TCR found here to a factor of $\sim$ 2. This work is combined in a companion analysis with tip measurements of nearby SN Ia hosts to measure $H_0$.

Filamentary structures in neutral hydrogen (H I) emission are well-aligned with the interstellar magnetic field, so H I emission morphology can be used to construct templates that strongly correlate with measurements of polarized thermal dust emission. We explore how the quantification of filament morphology affects this correlation. We introduce a new implementation of the Rolling Hough Transform (RHT) using spherical harmonic convolutions, which enables efficient quantification of filamentary structure on the sphere. We use this spherical RHT algorithm along with a Hessian-based method to construct H I-based polarization templates. We discuss improvements to each algorithm relative to similar implementations in the literature and compare their outputs. By exploring the parameter space of filament morphologies with the spherical RHT, we find that the most informative H I structures for modeling the magnetic field structure are the thinnest resolved filaments. For this reason, we find a $\sim10\%$ enhancement in the $B$-mode correlation with dust polarization with higher-resolution H I observations. We demonstrate that certain interstellar morphologies can produce parity-violating signatures, i.e., nonzero $TB$ and $EB$, even under the assumption that filaments are locally aligned with the magnetic field. Finally, we demonstrate that $B$ modes from interstellar dust filaments are mostly affected by the topology of the filaments with respect to one another and their relative polarized intensities, whereas $E$ modes are mostly sensitive to the shapes of individual filaments.

Binary neutron star merger (BNSM) offers an environment where fast neutrino-flavor conversion (FFC) can vividly occur, that potentially leads to a considerable change of neutrino radiation field. In this Letter, we investigate global features of FFC by general relativistic quantum kinetic neutrino transport simulations in spatial axisymmetry. Our result suggests that global advection of neutrinos plays a crucial role in FFC dynamics. Although flavor conversions occur ubiquitously in the early phase, they can be active only in a narrow region in the late phase. This region includes an ELN-XLN Zero Surface (EXZS), corresponding to a surface where electron-neutrinos lepton number (ELN) equals to heavy-leptonic one (XLN). The EXZS is not stationary, but dynamically evolve in a time scale of global advection. We also find that neutrinos can undergo a flavor swap when they pass through the EXZS, resulting in qualitatively different neutrino radiation fields between both sides of EXZS. Our result suggests that EXZS is one of the key ingredients to characterize FFC in BNSM.

Galaxy-scale strongly lensed systems have been shown to provide a unique technique for exploring the underlying physics of dark matter at sub-galactic scales. In the past, much attention was given to detecting and studying individual haloes in a strong lens system. In addition to the subhaloes, line-of-sight haloes contribute significantly to the small perturbations in lensed images. In prior work, we demonstrated that these line-of-sight haloes imprint a distinctive anisotropic signature and hence give rise to a detectable non-zero parity-even quadrupole moment in the effective convergence field's two-point correlation function. In this study, we show that these line-of-sight haloes also produce a non-zero curl component of the effective deflection field with a parity-odd quadrupole moment of the two-point function. These multipole moments have the ability to statistically separate line-of-sight haloes from dark matter substructure. In this paper, we examine how these multipole moments evolve in the presence of warm dark matter and self-interacting dark matter in terms of central density evolution and dark matter halo abundance. Importantly, we show that these different multipole moments display exquisite sensitivity to both the amplitude and the velocity dependence of the dark matter self-interaction cross-section. Our approach opens the door for strong lensing observations to probe dark matter self-interaction over a broad range of relative velocities.

Past observations and simulations predict an increasingly inhomogeneous gas distribution towards the outskirts of galaxy clusters, but the exact properties of such gas clumping are not yet well known. The outskirts of Abell 133 benefit from deep X-ray observations, with a 2.4 Ms ultra-deep Chandra exposure as well as eight archival Suzaku pointings, making it a unique laboratory to study the clumping of the intracluster medium. We searched for significant clump candidates, in particular aiming to identify those that could represent genuine ICM inhomogeneity. To further understand how clumping biases the thermodynamic profiles, we compared the measurements including and excluding the clump candidates. We jointly analyzed Chandra and Suzaku observations of Abell 133. We selected clump candidates with at least 2$\sigma$ significance based on the Chandra image and further discussed their origins using information from the DESI Legacy Imaging Surveys cluster catalogue, as well as the CFHT r-band image. We performed multiple rounds of Suzaku spectral analysis with different corrections for the underlying point sources and clump distribution, and compared the resulting thermodynamic profiles. We detected 16 clump candidates using Chandra, most of which are identified as background clusters or galaxies as opposed to intrinsic inhomogeneity. Even after the correction of the resolved clumps, the entropy profile approaching the outskirts still flattens, deviating from the power law model expected from self-similar evolution, which implies that unresolved clumping and other complex physics should contribute to the entropy flattening in the outskirts.

If the envelope of a massive star is not entirely removed during common envelope (CE) interaction with an orbiting compact (e.g., black hole [BH] or neutron star [NS]) companion, the residual bound material eventually cools, forming a centrifugally-supported disk around the binary containing the stripped He core. We present a time-dependent height-integrated model for the long-term evolution of post-CE circumbinary disks (CBD), accounting for mass and angular momentum exchange with the binary and irradiation heating by the He core and photoevaporation wind mass-loss. A large fraction of the CBD's mass is accreted prior to its outwards viscous spreading and wind-dispersal on a timescale ~10^{4}-10^{5} yr, driving significant changes in the binary separation, even for disks containing ~ 10% of the original envelope mass. Insofar that the CBD lifetime is comparable to the thermal (and, potentially, nuclear) timescale of the He core, over which a second mass-transfer episode onto the companion can occur, the presence of the CBD could impact the stability of this key phase. Disruption of the He core by the BH/NS would result in a jetted energetic explosion into the dense gaseous CBD (<~10^{15} cm) and its wind (>~ 10^{16} cm), consistent with the environments of luminous fast blue optical transients like AT2018cow. Evolved He cores which undergo core-collapse still embedded in their CBD could generate Type Ibn/Icn supernovae. Thousands of dusty wind-shrouded massive-star CBD may be detectable as extragalactic luminous infrared sources with the Roman Space Telescope; synchrotron radio nebulae powered by the CBD-fed BH/NS may accompany these systems.

We introduce the New-ANGELS program, an XMM-Newton survey of $\sim7.2\rm~deg^2$ area around M 31, which aims to study the X-ray populations in M 31 disk and the X-ray emitting hot gas in the inner halo of M 31 up to 30 kpc. In this first paper, we report the catalogue of 4506 detected X-ray sources, and attempt to cross-identify or roughly classify them. We identify 352 single stars in the foreground, 35 globular clusters and 27 supernova remnants associated with M 31, as well as 62 AGNs, 59 galaxies, and 1 galaxy clusters in the background. We uniquely classify 236 foreground stars and 17 supersoft sources based on their X-ray colors. X-ray binaries (83 LMXBs, 1 HMXBs) are classified based on their X-ray colors and X-ray variabilities. The remaining X-ray sources either have too low S/N to calculate their X-ray colors or do not have a unique classification, so are regarded as unclassified. The X-ray source catalogue is published online. Study of the X-ray source populations and the contribution of X-ray sources in the unresolved X-ray emissions based on this catalogue will be published in companion papers.

We present an X-ray spectrum of the diffuse X-ray background (DXRB) between 1.5 and 120 keV, as measured with the Low-Energy Detector (LE) and the High-Energy Detector (HE) aboard the Insight-HXMT satellite, based on 'blank-sky' observations. LE covers a nominal energy range of 1-15 keV and HE 20-250 keV, but calibration issues and data quality narrowed the energy range for this work. The LE background was directly measured with `blind' detector modules, while the HE background was derived from Earth-occultation data. With the LE data alone, the measured DXRB spectrum can be well described by a power law; fitting the LE and HE data jointly, however, a spectral cut-off must be introduced in the model to account for the measurements above 30 keV. Modelling the combined spectrum with a cut-off power law, the best-fit photon index is 1.40, normalisation $9.57$~$\rm ph~cm^{-2}~s^{-1}~keV^{-1}~sr^{-1} $ (at 1 keV), and cut-off energy 55 keV, after correcting for the effects of the Earth albedo and atmospheric emission (which are significant in the HE band). Based on the best-fit cut-off power law, we derived the spectral energy distribution (SED) of the DXRB. The shape of the SED is in general agreement with the published measurements, but the overall normalization is lower by varying amounts, except for the HEAO-1 result, with which our result is in good agreement.

In this Letter, we demonstrate that the inference of galaxy stellar masses via spectral energy distribution (SED) fitting techniques for galaxies formed in the first billion years after the Big Bang carries fundamental uncertainties owing to the loss of star formation history (SFH) information from the very first episodes of star formation in the integrated spectra of galaxies. While this early star formation can contribute substantially to the total stellar mass of high-redshift systems, ongoing star formation at the time of detection outshines the residual light from earlier bursts, hampering the determination of accurate stellar masses. As a result, order of magnitude uncertainties in stellar masses can be expected. We demonstrate this potential problem via direct numerical simulation of galaxy formation in a cosmological context. In detail, we carry out two cosmological simulations with significantly different stellar feedback models which span a significant range in star formation history burstiness. We compute the mock SEDs for these model galaxies at z=7 via 3D dust radiative transfer calculations, and then backwards fit these SEDs with Prospector SED fitting software. The uncertainties in derived stellar masses that we find for z>7 galaxies motivate the development of new techniques and/or star formation history priors to model early Universe star formation.

We present the optical spectroscopic evolution of SN~2023ixf seen in sub-night cadence spectra from 1.18 to 14 days after explosion. We identify high-ionization emission features, signatures of interaction with material surrounding the progenitor star, that fade over the first 7 days, with rapid evolution between spectra observed within the same night. We compare the emission lines present and their relative strength to those of other supernovae with early interaction, finding a close match to SN~2020pni and SN~2017ahn in the first spectrum and SN~2014G at later epochs. To physically interpret our observations we compare them to CMFGEN models with confined, dense circumstellar material around a red supergiant progenitor from the literature. We find that very few models reproduce the blended \NC{} emission lines observed in the first few spectra and their rapid disappearance thereafter, making this a unique diagnostic. From the best models, we find a mass-loss rate of $10^{-3}-10^{-2}$ \mlunit{}, which far exceeds the mass-loss rate for any steady wind, especially for a red supergiant in the initial mass range of the detected progenitor. These mass-loss rates are, however, similar to rates inferred for other supernovae with early circumstellar interaction. Using the phase when the narrow emission features disappear, we calculate an outer dense radius of circumstellar material $R_\mathrm{CSM, out}\sim5\times10^{14}~\mathrm{cm}$ and a mean circumstellar material density of $\rho=5.6\times10^{-14}~\mathrm{g\,cm^{-3}}$. This is consistent with the lower limit on the outer radius of the circumstellar material we calculate from the peak \Halpha{} emission flux, $R_\text{CSM, out}\gtrsim9\times10^{13}~\mathrm{cm}$.

We present a novel approach to inspecting galaxy spectra using sound, via their direct audio representation ('spectral audification'). We discuss the potential of this as a complement to (or stand-in for) visual approaches. We surveyed 58 respondents who use the audio representation alone to rate 30 optical galaxy spectra with strong emission lines. Across three tests, each focusing on different quantities measured from the spectra (signal-to-noise ratio, emission-line width, & flux ratios), we find that user ratings are well correlated with measured quantities. This demonstrates that physical information can be independently gleaned from listening to spectral audifications. We note the importance of context when rating these sonifications, where the order examples are heard can influence responses. Finally, we adapt the method used in this promising pilot study to spectral datacubes. We suggest that audification allows efficient exploration of complex, spatially-resolved spectral data.

We present an extensive, panchromatic photometric (UV, Optical, and NIR) and low-resolution optical spectroscopic coverage of a Type IIP supernova SN 2018gj that occurred on the outskirts of the host galaxy NGC 6217. From the V-band light curve, we estimate the plateau length to be ~ 70 +- 2 d, placing it among the very few well-sampled short plateau supernovae (SNe). With V-band peak absolute magnitude Mv < -17.0 +- 0.1 mag, it falls in the middle of the luminosity distribution of the Type II SNe. The colour evolution is typical to other Type II SNe except for an early elbow-like feature in the evolution of V-R colour owing to its early transition from the plateau to the nebular phase. Using the expanding photospheric method, we present an independent estimate of the distance to SN 2018gj. We report the spectral evolution to be typical of a Type II SNe. However, we see a persistent blue shift in emission lines until the late nebular phase, not ordinarily observed in Type II SNe. The amount of radioactive nickel (56Ni) yield in the explosion was estimated to be 0.026 +- 0.007 Msol. We infer from semi-analytical modelling, nebular spectrum, and 1-D hydrodynamical modelling that the probable progenitor was a red supergiant with a zero-age-main-sequence mass < 13 Msol. In the simulated hydrodynamical model light curves, reproducing the early optical bolometric light curve required an additional radiation source, which could be the interaction with the proximal circumstellar matter (CSM).

Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System (Gillon et al., 2017). Thanks to the recent launch of JWST, possible atmospheric constituents such as carbon dioxide (CO2) are now detectable (Morley et al., 2017, Lincowski et al., 2018}. Recent JWST observations of the innermost planet TRAPPIST-1 b showed that it is most probably a bare rock without any CO2 in its atmosphere (Greene et al., 2023). Here we report the detection of thermal emission from the dayside of TRAPPIST-1 c with the Mid-Infrared Instrument (MIRI) on JWST at 15 micron. We measure a planet-to-star flux ratio of fp/fs = 421 +/- 94 parts per million (ppm) which corresponds to an inferred dayside brightness temperature of 380 +/- 31 K. This high dayside temperature disfavours a thick, CO2-rich atmosphere on the planet. The data rule out cloud-free O2/CO2 mixtures with surface pressures ranging from 10 bar (with 10 ppm CO2) to 0.1 bar (pure CO2). A Venus-analogue atmosphere with sulfuric acid clouds is also disfavoured at 2.6 sigma confidence. Thinner atmospheres or bare-rock surfaces are consistent with our measured planet-to-star flux ratio. The absence of a thick, CO2-rich atmosphere on TRAPPIST-1 c suggests a relatively volatile-poor formation history, with less than 9.5 +7.5 -2.3 Earth oceans of water. If all planets in the system formed in the same way, this would indicate a limited reservoir of volatiles for the potentially habitable planets in the system.

We present the discovery and timing solutions of four millisecond pulsars (MSPs) discovered in the Arecibo 327 MHz Drift-Scan Pulsar Survey. Three of these pulsars are in binary systems, consisting of a redback (PSR J2055+1545), a black widow (PSR J1630+3550), and a neutron star-white dwarf binary (PSR J2116+1345). The fourth MSP, PSR J2212+2450, is isolated. We present the multi-year timing solutions as well as polarization properties across a range of radio frequencies for each pulsar. We perform a multi-wavelength search for emission from these systems and find an optical counterpart for PSR J2055+1545 in Gaia DR3, as well as a gamma-ray counterpart for PSR J2116+1345 with the Fermi-LAT telescope. Despite the close co-location of PSR J2055+1545 with a Fermi source, we are unable to detect gamma-ray pulsations, likely due to the large orbital variability of the system. This work presents the first two binaries found by this survey with orbital periods shorter than a day; we expect to find more in the 40% of the survey data which have yet to be searched.

We study a model of Symmetric Teleparallel gravity that is able to account for the current accelerated expansion of the universe without the need for dark energy component. We investigate this model by making use of dynamical system analysis techniques to identify the regions of the parameter space with viable cosmologies and constrain it using type Ia supernova (SnIa), cosmic microwave background (CMB) data and make forecasts using standard siren (SS) events. We conclude that this model is disfavored with respect to $\Lambda$CDM and forthcoming standard siren events can be decisive in testing the viability of the model.

In this White Paper for Nancy Grace Roman Space Telescope (Roman) science, we propose the Roman Survey of the Earth Transit Zone (RoSETZ), a transit search for rocky planets within the habitable zones (HZs) of stars located within the Earth Transit Zone (ETZ). The ETZ holds special interest in the search for extra-terrestrial intelligence (SETI) - observers on planets within the ETZ can see Earth as a transiting planet. RoSETZ would augment the Roman Galactic Bulge Time Domain Survey (GBTDS) as an additional field located $\sim 5$~degrees away from other GBTDS fields. Our simulations show that RoSETZ alone can find from 120 to 630 Earth-sized HZ planets around K- and M-type hosts, with the range reflecting different survey design assumptions. These yields are 5-20 times the number currently known. Such a sample will transform our knowledge of ``Eta-Earth'' ($\eta_{\oplus}$) -- the occurrence of Earth-sized HZ planets -- and would be the first catalogue of exoplanets selected in a manner optimized according to the Mutual Detectability targetted-SETI strategy. If it can be accommodated alongside the existing GBTDS design, we favour a RoSETZ-Max design that is observed for the duration of the GBTDS. If not, we show that a slimmed-down RoSETZ-Lite design, occupying two GBTDS seasons, would not significantly impact overall GBTDS exoplanet yields, even if time allocated to it had to come from time allocations to other fields. We argue that the angular separation of RoSETZ from other GBTDS fields permits self-calibration of systematic uncertainties that would otherwise hamper exoplanet demographic modelling of both microlensing and transit datasets. Other science possible with RoSETZ data include studies of small solar system bodies and high resolution 3D extinction mapping.

Self-interacting scalar field dark matter can be seen as an extension of the free case known as Fuzzy dark matter. On the other hand, current imagining black holes (BHs) observations provided by the Event Horizon Telescope (EHT) collaboration can not rule out the possibility that BHs can carry some amount of charge. Motivated by these aspects, and by the possibility of detecting DM through its gravitational imprints on BH observations, in this paper, we extend previous studies of accretion of self-interacting scalar field dark matter to the charged BH case. Our analysis is based on the assumption on spherically symmetric flow and employs a test fluid approximation. Concretely, we implement analytical and numerical approaches to investigate the impact of the charge on the energy flux. All analytical expressions are derived from scratch in Schwarzschild coordinates. From this analysis, we notice that the mass accretion rate efficiency is reduced up to $\sim 20\%$ for the maximum allowed charge. Considering the mass accretion rate of M87$^{\star}$ inferred from Polarization data of the EHT, we infer, as a main result, the conservative bound $ \lambda_4 > (1.49-10.2)( m / 1 \rm {eV} )^4$. This inference is based on the simple criterion that ensures the mass accretion rate caused by DM remains subdominant compared to the baryonic component.

The ESA Euclid mission is scheduled to launch on July 1st 2023. This White Paper discusses how Euclid observations of the Galactic Bulge Time Domain Survey (GBTDS) area could dramatically enhance the exoplanet science output of the Nancy Grace Roman Space Telescope (Roman). An early Euclid pre-imaging survey of the Roman GBTDS fields, conducted soon after launch, can improve proper motion determinations for Roman exoplanet microlenses that can yield a factor of up to $\sim 5$ improvement in exoplanet mass measurements. An extended Euclid mission would also enable the possibility of sustained simultaneous observations of the GBTDS by Euclid and Roman that would achieve large gains in several areas of Roman exoplanet science, including science that is impossible to achieve with Roman alone. These include: a comprehensive demographic survey for free-floating planets that includes precision mass measurements to establish the true nature of individual candidates; detection, confirmation and mass measurements of exomoons; direct exoplanet mass measurements through parallax and finite source size effects for a large sample of bound exoplanets detected jointly by Euclid and Roman; enhanced false-positive discrimination for the large samples of transiting planets that Roman will detect. Our main recommendation to NASA and ESA is to initiate a Joint Study Group as early as possible that can examine how both missions could best conduct a coordinated campaign. We also encourage flexibility in the GBTDS scheduling.

We perform correlation and periodicity search analyses on long-term multi-band light curves of the FSRQ 1510-089 observed by the space-based Fermi--Large Area Telescope in gamma-rays, the SMARTS and Steward Observatory telescopes in optical and near-infrared (NIR) and the 13.7 m radio telescope in Metsahovi Radio Observatory between 2008 and 2018. The z-transform discrete correlation function method is applied to study the correlation and possible time lags among these multi band light curves. Among all pairs of wavelengths, the gamma-ray vs. optical/NIR and optical vs. NIR correlations show zero time lags; however, both the gamma-ray and optical/NIR emissions precede the radio radiation. The Generalized Lomb-Scargle periodogram, Weighted Wavelet Z-transform, and REDFIT techniques are employed to investigate the unresolved-core-emission dominated 37 GHz light curve and yield evidence for a quasi-period around 1540 days, although given the length of the whole data set it cannot be claimed to be significant. We also investigate the optical/NIR color variability and find that this source shows a simple redder-when-brighter behavior over time, even in the low flux state.

We perform a systematic study of evolutionary stages and stellar masses of young stellar objects (YSOs) in the Large Magellanic Cloud (LMC) to investigate properties of star formation of the galaxy. There are 4825 sources in our YSO sample, which are constructed by combining the previous studies identifying YSOs in the LMC. Spectral energy distributions of the YSOs from optical to infrared wavelengths were fitted with a model consisting of stellar, polycyclic aromatic hydrocarbon and dust emissions. We utilize the stellar-to-dust luminosity ratios thus derived to study the evolutionary stages of the sources; younger YSOs are expected to show lower stellar-to-dust luminosity ratios. We find that most of the YSOs are associated with the interstellar gas across the galaxy, which are younger with more gases, suggesting that more recent star formation is associated with larger amounts of the interstellar medium (ISM). N157 shows a hint of higher stellar-to-dust luminosity ratios between active star-forming regions in the LMC, suggesting that recent star formation in N157 is possibly in later evolutionary stages. We also find that the stellar mass function tends to be bottom-heavy in supergiant shells (SGSs), indicating that gas compression by SGSs may be ineffective in compressing the ISM enough to trigger massive star formation. There is no significant difference in the stellar mass function between YSOs likely associated with the interface between colliding SGSs and those with a single SGS, suggesting that gas compression by collisions between SGSs may also be ineffective for massive star formation.

We present early-phase panchromatic photometric and spectroscopic coverage spanning far-ultraviolet (FUV) to the near-infrared (NIR) regime of the nearest hydrogen-rich core-collapse supernova in the last 25 years, SN~2023ixf. We observe early `flash' features in the optical spectra due to a confined dense circumstellar material (CSM). We observe high-ionization absorption lines Fe II, Mg II in the ultraviolet spectra from very early on. We also observe a multi-peaked emission profile of H-alpha in the spectrum beginning ~16 d, which indicates ongoing interaction of the SN ejecta with a pre-existing shell-shaped CSM having an inner radius of ~ 75 AU and an outer radius of ~140 AU. The shell-shaped CSM is likely a result of enhanced mass loss ~ 35 - 65 years before the explosion assuming a standard Red-Supergiant wind. Spectral modeling of the FUV, NUV, and the optical spectra during 9-12 d, using the radiative transfer spectrum synthesis code TARDIS indicates that the supernova ejecta could be well represented by a progenitor elemental composition greater than solar abundances. Based on early light curve models of Type II SNe, we infer that the nearby dense CSM confined to ~7+-3e14~cm(~45 AU) is a result of enhanced mass loss ~1e-(3.0+-0.5) Msol/yr two decades before the explosion.

In order to develop a complete theory of star formation, one essentially needs to know two things: what collapses, and how long it takes. This is the second paper in a series, where we query how long a parcel of gas takes to collapse and the process it undergoes. We embed pseudo-Lagrangian tracer particles in simulations of collapsing molecular clouds, identify the particles that end in dense knots, and then examine the collapse history of the gas. We find a nearly universal behavior of cruise-then-collapse. We identify gas the moment before it collapses, $t_{\rm{sing}}$, and examine how it transitions to high density. We find that the time to collapse is uniformly distributed between $0.25 t_{\rm{ff}}$ and the end of the simulation at $\sim 1 t_{\rm{ff}}$, and that the collapse duration is universally short, $\Delta t \sim 0.1 t_{\rm{ff}}$. We find that the collapse of each core happens by a process akin to violent relaxation, wherein a fast reordering of the potential and kinetic energies occurs, in $0.1 t_{\rm{ff}}$, after which a virialized object remains. We describe the collapse in four stages; collection, hardening, singularity, and mosh. Collection sweeps low density gas into moderate density. Hardening brings kinetic and gravitational energies into quasi-equipartition. Singularity is the free-fall collapse, forming a virialized object in $\sim 0.1 t_{\rm{ff}}$. Mosh encompasses tidal dynamics of sub clumps and nearby cores during the collapse. In this work we focus primarily on isolated clumps. With this novel lens we can observe the details of collapse.

There is growing evidence that high-mass star formation and hub-filament systems (HFS) are intricately linked. The gas kinematics along the filaments and the forming high-mass star(s) in the central hub are in excellent agreement with the new generation of global hierarchical high-mass star formation models. In this paper, we present an observational investigation of a typical HFS cloud, G310.142+0.758 (G310 hereafter) which reveals unambiguous evidence of mass inflow from the cloud scale via the filaments onto the forming protostar(s) at the hub conforming with the model predictions. Continuum and molecular line data from the ATOMS and MALT90 surveys are used that cover different spatial scales. Three filaments (with total mass $5.7\pm1.1\times 10^3~M_{\odot}$) are identified converging toward the central hub region where several signposts of high-mass star formation have been observed. The hub region contains a massive clump ($1280\pm260~M_{\odot}$) harbouring a central massive core. Additionally, five outflow lobes are associated with the central massive core implying a forming cluster. The observed large-scale, smooth and coherent velocity gradients from the cloud down to the core scale, and the signatures of infall motion seen in the central massive clump and core, clearly unveil a nearly-continuous, multi-scale mass accretion/transfer process at a similar mass infall rate of $\sim 10^{-3}~M_{\odot}~yr^{-1}$ over all scales, feeding the central forming high-mass protostar(s) in the G310 HFS cloud.

Comprehensive analysis of optical spectroscopy and space photometry of the solar type eclipsing binary system KIC\,4832197 is presented. The system is composed of F7V + F9V components with masses of $M_{1}=1.16\pm0.12~M_{\odot}$, $M_{2}=1.07\pm0.10~M_{\odot}$ and radii of $R_{1}=1.26\pm0.04~R_{\odot}$, $R_{2}=1.03\pm0.03~R_{\odot}$. Position of the components on $Log~T_{eff}-Log~L/L_{\odot}$ plane suggests an age of $2.8\pm0.8~Gyr$ for the system. Inspection of out-of-eclipse brightness in time reveals wave-like variability pattern, whose amplitude and shape quickly change in order of days. Frequency analysis of this variability results in two significant peaks in amplitude spectrum, which are interpreted as rotational modulation of spots on the components. Assuming both spots are on the same component, a lower limit for differential rotation coefficient is computed as $k=0.12$, which is weaker compared to the solar value of $k_{\odot} = 0.189$.

The Cassini-Huygens mission has transformed our understanding of Titan from a hazy veiled moon to a place surprisingly like the Earth, with terrestrial physical processes such as wind, rainfall, and erosion shaping the landscape albeit with entirely different chemistry and temperatures. Dragonfly, a single element mission which fits within the New Frontiers cost cap will arrive at Titan in 2034, and perform in-situ investigations of the organic materials on the surface. However, its detailed investigations will be limited to region within its short flight range. The big gaps in our understanding of Titan global topography, climate, and upper atmospheric chemistry which can only investigated from an orbiter around Titan will remain to be addressed by a future orbiter mission. Due to the challenges of attaining orbit, past Titan orbiter concepts have been beyond the New Frontiers cost cap. The present study explores the use of drag modulation aerocapture for a Titan Orbiter which fits within New Frontiers. The study shows how a Dragonfly-like lander, and a Titan orbiter which each individually fit within the New Frontiers cost cap, when combined together can provide the science data return equivalent to a Flagship-class mission.

We characterize the physical properties of star-formation driven outflows in a sample of 29 local dwarf galaxies drawn from the Dwarf Galaxy Survey. We make use of Herschel/PACS archival data to search for atomic outflow signatures in the wings of individual [CII] 158 um spectra and in their stacked line profile. We find a clear excess of emission in the high-velocity tails of 11 sources which can be explained with an additional broad component in the modeling of their spectra. The remaining objects are likely hosts of weaker outflows that can still be detected in the average stacked spectrum. In both cases, we estimate the atomic mass outflow rates which result to be comparable with the star-formation rates of the galaxies, implying mass-loading factors of the order of unity. Outflow velocities in all the 11 galaxies with individual detection are larger than (or compatible with) the escape velocities of their dark matter halos, with an average fraction of 40% of gas escaping into the intergalactic medium (IGM). Depletion timescales due to outflows are lower than those due to gas consumption by star formation in most of our sources, ranging from hundred million to a few billion years. Our outflows are mostly consistent with momentum-driven winds generated by the radiation pressure of young stellar populations on dust grains, although the energy-driven scenario is not excluded if considering a coupling efficiency up to 20% between the energy injected by supernova (SN) and the interstellar medium. Our results suggest that galactic outflows can regulate the star formation history of dwarf galaxies as they are able to enrich with metals the circumgalactic medium of these sources, bringing on average a non-negligible amount of gas into the IGM. Our findings are suitable for tuning chemical evolution models attempting to describe the physical processes shaping the evolution of dwarf galaxies.

The kinetic description of relativistic plasmas in the presence of time-varying and spatially non-uniform electromagnetic fields is a fundamental theoretical issue both in astrophysics and plasma physics. This refers, in particular, to the treatment of collisionless and strongly-magnetized plasmas in the presence of intense radiation sources. In this paper the problem is investigated in the framework of a covariant gyrokinetic treatment for Vlasov-Maxwell equilibria. The existence of a new class of kinetic equilibria is pointed out, which occur for spatially-symmetric systems. These equilibria are shown to exist in the presence of non-uniform background EM fields and curved space-time. In the non-relativistic limit this feature permits the determination of kinetic equilibria even for plasmas in which particle energy is not conserved due to the occurrence of explicitly time-dependent EM fields. Finally, absolute stability criteria are established which apply in the case of infinitesimal symmetric perturbations that can be either externally or internally produced.

We report ALMA detections of [CII] and dust continuum in Az9, a multiply-imaged galaxy behind the Frontier Field cluster MACSJ0717.5+3745. The bright [CII] emission line provides a spectroscopic redshift of z = 4.274. This strongly lensed (mu = 7 +/- 1) galaxy has an intrinsic stellar mass of only 2e9 Msun and a total star formation rate of 26 Msun/yr (~80% of which is dust obscured). Using public magnification maps, we reconstruct the [CII] emission in the source plane to reveal a stable, rotation-dominated disk with V/sigma = 5.3, which is > 2x higher than predicted from simulations for similarly high-redshift, low-mass galaxies. In the source plane, the [CII] disk has a half-light radius of 1.8 kpc and, along with the dust, is spatially offset from the peak of the stellar light by 1.4 kpc. Az9 is not deficient in [CII]; L[CII]/LIR = 0.0027 consistent with local and high redshift normal star forming galaxies. While dust-obscured star formation is expected to dominate in higher mass galaxies, such a large reservoir of dust and gas in a lower mass disk galaxy 1.4 Gyr after the Big Bang challenges our picture of early galaxy evolution. Furthermore, the prevalence of such low-mass dusty galaxies has important implications for the selection of the highest redshift dropout galaxies with JWST. As one of the lowest stellar mass galaxies at z > 4 to be detected in dust continuum and [CII], Az9 is an excellent laboratory in which to study early dust enrichment in the interstellar medium.

We present a cosmic density field reconstruction method that augments the traditional reconstruction algorithms with a convolutional neural network (CNN). Following Shallue $\&$ Eisenstein (2022), the key component of our method is to use the $\textit{reconstructed}$ density field as the input to the neural network. We extend this previous work by exploring how the performance of these reconstruction ideas depends on the input reconstruction algorithm, the reconstruction parameters, and the shot noise of the density field, as well as the robustness of the method. We build an eight-layer CNN and train the network with reconstructed density fields computed from the Quijote suite of simulations. The reconstructed density fields are generated by both the standard algorithm and a new iterative algorithm. In real space at $z=0$, we find that the reconstructed field is $90\%$ correlated with the true initial density out to $k\sim 0.5 h{\rm Mpc}^{-1}$, a significant improvement over $k\sim 0.2 h{\rm Mpc}^{-1}$ achieved by the input reconstruction algorithms. We find similar improvements in redshift space, including an improved removal of redshift space distortions at small scales. We also find that the method is robust across changes in cosmology. Additionally, the CNN removes much of the variance from the choice of different reconstruction algorithms and reconstruction parameters. However, the effectiveness decreases with increasing shot noise, suggesting that such an approach is best suited to high density samples. This work highlights the additional information in the density field beyond linear scales as well as the power of complementing traditional analysis approaches with machine learning techniques.

V445 Puppis, the only known Galactic helium nova, is a unique test-bed to verify supernova (SN) theories in the single degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo a SN detonation. In this context, this study estimates the dust and ejecta masses in the 2000 November eruption of V445 Pup. Subsequent to its outburst, the star became cocooned in a dust envelope. An analysis of the spectral energy distribution (SED) of the dust using infrared data shows that V445 Pup produced at least $10^{-3}$ solar masses of dust which is unprecedented for a classical or recurrent nova. The SED can be explained by a combination of a cold dust component at 105 +/- 10 K, mass (1.9 +/- 0.8) $\times 10^{-3}$ solar masses, and a warm dust component at 255 +/- 10 K, mass (2.2 +/- 1.2) $\times 10^{-5}$ solar masses. For a conservative choice of the gas-to-dust mass ratio in the range 10--100, the mass of the ejecta is 0.01--0.1 solar masses. Such a high mass range raises the question: why did V445 Pup not detonate as a Type 1a SN as is predicted in certain double-detonation sub-Chandrasekhar supernovae formalisms? We re-examine the nature of V445 Pup and discuss its role as a potential SN progenitor.

We have built and characterized a six-telescope near-infrared discrete beam combiner (DBC) for stellar interferometry using the technique of ultrafast laser inscription (ULI). The 3D beam combiner consists of evanescently coupled waveguides fabricated in borosilicate glass, with a throughput of around 56%. Devices of two design types are characterized over the astronomical J and H band. Using the 15 non-redundant combinations of pairs, we populate the elements of the visibility-to-pixel matrix (V2PM) of the beam combiner using a two-input Michelson interferometer setup. We identify the complex visibility as wavelength dependent, with different optimum wavelengths for the two types of devices. For the design that includes a fan-in region, a baseline-averaged mean visibility amplitude of 1.05 and relative precision of 2.9% and 3.8% are extracted for characterization at 1328 nm and 1380 nm, respectively. Operation is also possible in the H-band, with a relative precision of 4.8% at 1520 nm. Broadband characterization is subject to dispersion effects, but gives similar performance results to their monochromatic counterparts in the J-band at 1350 nm.

We present a study of the Ca II K and IR-triplet lines in a sample of Classical T Tauri stars in the Chamaeleon I star-forming region. We study X-shooter spectra of the stars in the sample and find that in some of these stars the Ca II lines are much weaker than expected from their H line fluxes and mass accretion rate. Since the Ca II K lines have characteristic magnetospheric accretion line profiles and the magnetospheric flows feed directly from the inner disk, we interpret the Ca deficit in terms of depletion due to processes happening in the disk. To test this hypothesis, we define a coarse depletion indicator using the flux of the Ca II K line and show that it correlates with disk properties. In particular, using indicators extracted from Spitzer/IRS spectra, we obtain that all the transitional and pre-transitional disks of the sample show depletion, consistent with trapping of refractories in pressure bumps created by planets and/or in the planets themselves. We find full disks with Ca depletion in the sample that also show indications of advanced dust evolution. We apply magnetospheric accretion models to fit the Balmer and Ca II line fluxes of a star showing clear Ca depletion and derive a Ca abundance in its inner disk of about 17% solar.

Despite multiple previous searches, no transiting planets have yet been identified within a globular cluster. This is believed to be due to a combination of factors: the low metallicities of most globular clusters suggests that there is significantly less planet-forming material per star in most globular clusters relative to the solar neighborhood, the high likelihood of dynamical interactions can also disrupt planetary orbits, and the data available for globular clusters is limited. However, transiting planets have been identified in open clusters, indicating that there may be planets in more massive clusters that have simply gone undetected, or that more massive clusters inhibit planet formation. Less than two degrees away from the nominal Galactic Bulge Time Domain Survey footprint, two globular clusters, NGC 6522 and NGC 6528, can be simultaneously observed by the Roman telescope during the Galactic Bulge Time Domain Survey. These clusters are comparable in mass (1-2 x 10$^5$ solar masses) and age (12 Gyr), but feature drastically different average metallicities: NGC 6522 has an average [Fe/H] $\sim$ -1.3, while NGC 6528 has an average [Fe/H] $\sim$ -0.1. If no transiting planets are detected in one season of time domain observations of these clusters, this would indicate a difference in planet occurrence among field stars and globular clusters at >3-$\sigma$ significance even after accounting for metallicity, which could be enhanced to >5-$\sigma$ significance with similar observations of another nearby field hosting a metal-rich globular cluster. Additionally, time domain observations of NGC 6522 and NGC 6528 will detect variable stars in both clusters, testing the connection between stellar variability and binary fraction to metallicity and cluster environment, as well as testing the dependence of exoplanet yields on stellar density and distance from the Galactic midplane.

In this empirical work, we aim to quantify the systematic uncertainties in stellar mass $(M_\star)$ estimates made from spectral energy distribution (SED) fitting through stellar population synthesis (SPS), for galaxies in the local Universe, by using the dynamical mass $(M_\text{dyn})$ estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high dimensional space of galaxy properties; size $(R_e)$, velocity dispersion $(\sigma_e)$, surface brightness $(I_e)$, mass-to-light ratio $(M_\star/L)$, rest-frame colour, S\'ersic index $(n)$ and dynamical mass $(M_\text{dyn})$; accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in $M_\star/M_\text{dyn}$ is driven by $\sigma_e$, S\'ersic index and colour. We use these parameters to calibrate an SED-independent $M_\star$ estimator, $\hat{M}_\star$. We find the random scatter of the relation $M_\star-\hat{M}_\star$ to be $0.108\text{dex}$ and $0.147\text{dex}$ for quiescent and star-forming galaxies respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, star formation rate) and spectral indices (H$\alpha$, H$\delta$, $D_n4000)$. For quiescent galaxies, $\sim65\%$ of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only $\sim13\%$ of the scatter. These results leave us with remaining unmodelled scatters of $0.055\text{dex}$ and $0.122\text{dex}$ for quiescent and star-forming galaxies respectively. This can be interpreted as a conservative limit on the precision in $M_\star$ that can be achieved via simple SPS-modelling.

RR Lyrae stars are one of the primary distance indicators for old stellar populations such as globular clusters, dwarf galaxies and galaxies. Typically, fundamental-mode RR Lyr stars are used for distance measurements, and their accuracy is strongly limited by the dependence of absolute magnitudes on metallicity, in both the optical and infrared bands. Here, we report the discovery of a period-(period ratio)-metallicity relation for double-mode RR Lyr stars, which can predict metallicity as accurately as the low-resolution spectra. With theoretical and observational evidence, we propose that the period-luminosity relation of double-mode RR Lyr stars is not affected by the metallicity. Combining the Large Magellanic Cloud distance and Gaia parallaxes, we calibrate the zero point of the period-luminosity relation to an error of 0.022 mag, which means that in the best case double-mode RR Lyr stars can anchor galaxy distances to an accuracy of 1.0%. For four globular clusters and two dwarf galaxies, we obtain distances using double-mode RR Lyr stars with a distance accuracy of 2-3% and 1-2%, respectively. With future telescopes such as the China Space Station Telescope and the Vera C. Rubin Observatory, double-mode RR Lyr stars will be established as an independent distance ladder in the near-field universe.

The oscillating pressure of the ultralight scalar dark matter (DM) can induce the oscillation of the local gravitational potential. Similar to the time-dependent frequency shift for the pulse signals of pulsars, the oscillation of the local gravitational potential can induce a time-dependent frequency shift (or frequency modulation) for quasi-monochromatic gravitational wave (GW) signals from galactic white dwarf (WD) binaries. To make this effects detectable, we suppose that some galactic WD binaries are located in the DM clumps/subhalos where the energy density of DM is about eight orders of magnitude higher than that at the position of the Earth. Turn to the fisher information matrix, we find that the amplified GW frequency modulation induced by the ultralight scalar DM with mass $m=1.67\times10^{-23}-4.31\times10^{-23}[{\rm eV}/c^2]$ can be detected by LISA.

To accurately measure a star's atmospheric parameters and chemical abundances, it is crucial to have high-quality spectra. Analysing the detailed chemical abundances of groups of stars can help us better understand nucleosynthesis, galactic chemical enrichment, and stellar evolution. In this study, we explored whether stellar spots can affect a star's inferred metallicity and, if so, where the impact is the strongest. To investigate this, we created synthetic infrared spectra that included stellar spots for a sample of main-sequence stars younger than the sun. We then applied two models to the data: one that accounted for spots and one that did not. From this, we can determine the bias introduced when fitting spotted spectra with a non-spotted model and how this bias varies with different parameters. Our findings revealed that fitting spotted spectra with a non-spotted model can introduce a scatter of up to 0.05 dex in the inferred metallicity, especially for stars with high levels of spot coverage. This bias is similar in magnitude to other relevant effects, such as atomic diffusion, radiative levitation, or non-local thermodynamic equilibrium. We also found that the effect is most pronounced in young stars and decreases with age. These results suggest that stellar spots can introduce a systematic uncertainty in metallicity that is not currently accounted for in spectroscopic analysis. This could potentially limit scientific inferences for population-level studies of young stars and differential abundance analyses.

Observational evidence points to a red supergiant (RSG) progenitor for SN 2023ixf. The progenitor candidate has been detected in archival images at wavelengths (>0.6 micron) where RSGs typically emit profusely. This object is distinctly variable in the infrared (IR). We characterize the variability using pre-explosion mid-IR (3.6 and 4.5 micron) Spitzer and ground-based near-IR (JHKs) archival data jointly covering a duration of around 19 yr. The IR light curves exhibit significant variability with RMS amplitudes in the range of 0.2-0.4 mag, increasing with decreasing wavelength. From a robust period analysis of the more densely sampled Spitzer data, we measure a period of 1091+/-71 days. We demonstrate using Gaussian Process modeling that this periodicity is also present in the near-IR light curves, thus indicating a common physical origin, which is likely pulsational instability also seen in other RSGs. We use the period-luminosity relation for RSGs from the literature to derive a value of M_K=-11.58+/-0.12 mag, corresponding to log(L/L_sun) in the range 5.2-5.5 dex assuming an M spectral type for the RSG progenitor candidate. This gives an independent estimate of its luminosity, unaffected by uncertainties in extinction and distance. Assuming the progenitor candidate underwent enhanced dust-driven mass-loss during the time of these archival observations, and using an empirical period-luminosity-based mass-loss prescription, we obtain a mass-loss rate of around (2-4)x10^-4 M_sun/yr. Comparing the above luminosity with stellar evolution models, we infer an initial mass for the progenitor candidate of 20+/-4 M_sun, making this one of the most massive progenitors for a Type II SN detected to-date.

Motivated by cosmic ray (CR) re-acceleration at a potential Galactic Wind Termination Shock (GWTS), we present a numerical model for time-dependent Diffusive Shock Acceleration (DSA). We use the stochastic differential equation solver (DiffusionSDE) of the cosmic ray propagation framework CRPropa3.2 with two modifications: An importance sampling module is introduced to improve statistics at high energies by keeping the simulation time short. An adaptive time step is implemented in the DiffusionSDE module. This ensures to efficiently meet constraints on the time and diffusion step, which is crucial to obtain the correct shock spectra. The time evolution of the spectrum at a one-dimensional planar shock is verified against the solution obtained by the grid-based solver VLUGR3 for both energy-independent and energy-dependent diffusion. We show that the injection of pre-accelerated particles can lead to a broken power law spectrum in momentum if the incoming spectrum of CRs is harder than the reaccelerated spectrum. If the injected spectrum is steeper, the shock spectrum dominates at all energies. We finally apply the developed model to the GWTS by considering a spherically symmetric shock, a spiral Galactic magnetic field, and anisotropic diffusion. The time-dependent spectrum at the shock is modeled as a basis for further studies.

Context. Adaptive optics (AO) is now a tool commonly deployed in astronomy. The real time correction of the atmospheric turbulence that AO enables allows telescopes to perform close to the diffraction limit at the core of their point spread function (PSF). Among other factors, AO-corrected PSFs depend on the ability of the wavefront corrector (WFC), generally a deformable mirror, to fit the incident wavefront corrugations. Aims. In this work, we focus on this error introduced by the WFC, the so-called fitting error. To date, analytical models only depend on the WFC cut-off frequency, and Monte Carlo simulations are the only solution for studying the impact of the WFC influence function shape on the AO-corrected PSF. We aim to develop an analytical model accounting for the influence function shape. Methods. We first obtain a general analytical model of the fitting error structure function. With additional hypotheses, we then derive an analytical model of the AO-corrected power spectral density. These two analytical solutions are compared with Monte Carlo simulations on different ideal profiles (piston, pyramid, Gaussian) as well as with real hardware (DM192 from ALPAO). Results. Our analytical predictions show a very good agreement with the Monte Carlo simulations. We show that in the image plane, the depth of the correction as well as the transition profile between the AO-corrected area and the remaining turbulent halo depend on the influence functions of the WFC. We also show that the generally assumed hypothesis of stationarity of the AO correction is actually not met. Conclusions. As the fitting error is the intrinsic optimal limit of an AO system, our analytical model allows for the assessment of the theoretical limits of extreme AO systems limited by the WFC in high-contrast imaging through a context where other errors become comparable.

We report the serendipitous discovery of an extremely intermittent radio pulsar, PSR J1710-3452, with a relatively long spin period of 10.4 s. The object was discovered through the detection of 97 bright radio pulses in only one out of 66 epochs of observations spanning almost three years. The bright pulses have allowed the source to be localised to a precision of 0.5" through radio imaging. We observed the source location with the Swift X-ray telescope but did not detect any significant X-ray emission. We did not identify any high-energy bursts or multi-frequency counterparts for this object. The solitary epoch of detection hinders the calculation of the surface magnetic field strength, but the long period and the microstructure in the single-pulses resembles the emission of radio-loud magnetars. If this is indeed a magnetar, it is located at a relatively high Galactic latitude (2.9 degree), making it potentially one of the oldest and the most intermittent magnetars known in the Galaxy. The very short activity window of this object is unique and may point towards a yet undetected population of long period, highly transient radio emitting neutron stars.

This Letter reports the first observational estimate of the heating rate in the slowly expanding solar corona. The analysis exploits the simultaneous remote and local observations of the same coronal plasma volume with the Solar Orbiter/Metis and the Parker Solar Probe instruments, respectively, and relies on the basic solar wind magnetohydrodynamic equations. As expected, energy losses are a minor fraction of the solar wind energy flux, since most of the energy dissipation that feeds the heating and acceleration of the coronal flow occurs much closer to the Sun than the heights probed in the present study, which range from 6.3 to 13.3 solar radii. The energy deposited to the supersonic wind is then used to explain the observed slight residual wind acceleration and to maintain the plasma in a non-adiabatic state. As derived in the Wentzel-Kramers-Brillouin limit, the present energy transfer rate estimates provide a lower limit, which can be very useful in refining the turbulence-based modeling of coronal heating and subsequent solar wind acceleration.

In this work, we study a heterogeneous group of seven stellar systems for the first time. Despite their different distances or spectral types, all of them belong to a very rare group of quadruple systems of 2+2 architecture, where both of the inner pairs harbor eclipsing binaries. These systems are: ASASSN-V J102911.57-522413.6 (inner periods 0.57272, and 3.79027 days), V1037 Her (0.78758 and 5.80348 days), WISE J181904.2+241243 (0.36713 and 0.41942 days), V2894 Cyg (2.57434 and 1.30579 days), NSVS 5725040 (1.79368 and 0.76794 days), WISE J210230.8+610816 (1.84324 and 0.57159 days), and ZTF J220518.78+592642.1 (2.79572 and 3.34615 days). Their outer mutual periods are: 9.3, 25.4, 18.7, 27.5, 2.6, 2.2, and 14.0 yr, respectively. These outer periodicities were derived using longer time span of photometric observations of these systems and analysing their period changes of both inner pairs via ETVs (eclipse-timing variations). Most of these studied systems are detached, as evidenced by the proper modelling of their light curves. A few of them show significant eccentric orbits with apsidal motion (e.g. V2894 Cyg, and NSVS 5725040). Further spectroscopic follow-up observations would offer a better characterization of the component star's parameters (for e.g. NSVS 5725040), as well as a potential interferometric detection of the systems as real doubles on their mutual orbits (for e.g. V1037 Her). A rather interesting excess of systems close to a 3:2 mean motion resonance is seen only for early spectral-type stars with higher temperatures.

We present the identification and analysis of an X-ray selected AGN sample that lie within the local ($z < 0.35$) galaxy population. From a parent sample of 22,079 MPA-JHU (based on SDSS DR8) galaxies, we identified 917 galaxies with central, excess X-ray emission (from 3XMM-DR7) likely originating from an AGN. We measured the host galaxies' star formation rates and classified them as either star-forming or quiescent based on their position relative to main sequence of star formation. Only 72% of the X-ray selected sample were identified as AGN using BPT selection; this technique is much less effective in quiescent hosts, only identifying 50% of the X-ray AGN. We also calculated the growth rates of the black holes powering these AGN in terms of their specific accretion rate ($\propto \mathrm{L_X/M_*}$) and found quiescent galaxies, on average, accrete at a lower rate than star-forming galaxies. Finally, we measured the sensitivity function of 3XMM so we could correct for observational bias and construct probability distributions as a function of accretion rate. AGN were found in galaxies across the full range of star formation rates ($\log_{10} \mathrm{SFR/M_\odot\ yr^{-1}} = -3\ \mathrm{to}\ 2$) in both star-forming and quiescent galaxies. The incidence of AGN was enhanced by a factor 2 (at a 3.5$\sigma$ significance) in star-forming galaxies compared to quiescent galaxies of equivalent stellar mass and redshift, but we also found a significant population of AGN hosted by quiescent galaxies.

Studying chemistry and chemical composition is fundamental to go back to formation history of planetary systems. We propose here to have another look at five targets to better determine their composition and the chemical mechanisms that take place in their atmospheres. We present a re-analysis of five Hot Jupiters, combining multiple instruments and using Bayesian retrieval methods. We compare different combinations of molecules present in the simulated atmosphere, different chemistry types as well as different clouds parametrization. As a consequence of recent studies questioning the detection of Na and K in the atmosphere of HD 209458b as being potentially contaminated by stellar lines when present, we study the impact on other retrieval parameters of misinterpreting the presence of these alkali species. We use spatially scanned observations from the grisms G102 and G141 of the WFC3 on HST, with a wavelength coverage of $\sim$0.8 to $\sim$1.7 microns. We analyse these data with the publicly available Iraclis pipeline. We added to our datasets STIS observations to increase our wavelength coverage from $\sim$0.4 to $\sim$1.7 microns. We then performed a Bayesian retrieval analysis with the open-source TauREx using a nested sampling algorithm. We explore the influence of including Na and K on the retrieval of the molecules from the atmosphere. Our data re-analysis and Bayesian retrieval are consistent with previous studies but we find small differences in the retrieved parameters. After all, Na and K has no significant impact on the properties of the planet atmospheres. Therefore, we present here our new best-fit models, taking into account molecular abundances varying freely and equilibrium chemistry. This work is a preparation for a future addition of more sophisticated representation of chemistry taking into account disequilibrium effects such as vertical mixing and photochemistry.

As it is suggested in \cite{Sakstein:2019fmf, CarrilloGonzalez:2020oac}, one can dynamically introduce the coincidence time-scale for EDE in the framework of a particular mass-varying-neutrino-model as a time at which neutrinos constituting the cosmic neutrino background enter the non-relativistic regime. The model does not predict, however, the right amount of EDE density because of smallness of neutrino masses. One may hope to adjust the parameters in such a way as to ensure that the two-loop contributions are kept small while at the same time the effective mass for scalar field that enters the expression of zero-point-energy (for the field trapped in the minimum of effective potential) is sufficient for explaining the needed amount of EDE. Unfortunately, the answer is not in the affirmative.

To assess the number of life-bearing worlds in astrophysical environments, it is necessary to take the intertwined processes of abiogenesis (birth), extinction (death), and transfer of life (migration) into account. We construct a mathematical model that incorporates this trio of mechanisms and accordingly derive the probability distribution function and other statistical properties (e.g., mean) for the number of worlds with biospheres. We show that a given astrophysical setting may become eventually saturated with life if the rate of successful transfers of organisms is higher than the extinction rate of biospheres. Based on the available data, we suggest that this criterion might be fulfilled for star-forming clusters (and perhaps the Galactic bulge under optimal circumstances), thereby indicating that such regions could constitute promising abodes for hosting and detecting life.

Relativistic jets from (supermassive) black holes are typically observed in non-thermal emission, caused by highly-relativistic electrons. Here, we study the interrelation between three-dimensional (special) relativistic magnetohydrodynamics, and particle acceleration in these jets. We inject Lagrangian particles into the jet that are accelerated through diffusive shock acceleration and radiate energy via synchrotron and inverse Compton processes. We investigate the impact of different injection nozzles on the jet dynamics, propagation, and the spectral energy distribution of relativistic particles. We consider three different injection nozzles -- injecting steady, variable and precessing jets. These jets evolve with substantially different dynamics, driving different levels of turbulence and shock structures. The steady jet shows a strong, stationary shock feature, resulting from a head-on collision with an inner back-flow along the jet axis - a jet inside a jet. This shock represents a site for highly-efficient particle acceleration for electrons upto a few tens of TeV and should be visible in emission as a jet knot. Overall, we find that the total number of shocks is more essential for particle acceleration than the strength of the shocks. The precessing jet is most efficient in accelerating electrons to high energies reaching even few hundred TeVs, with power-law index ranging from 2.3 to 3.1. We compare different outflow components, such as jet and the entrained material concerning particle acceleration. For the precessing nozzle, particle acceleration in the entrained material is as efficient as in the jet stream. This is due to the higher level of turbulence induced by the precession motion.

Context. We present an analysis of our high-resolution relativistic-hydrodynamics model of the stellar- and pulsar-wind interaction in the LS-5039 system. Aims. With our high-resolution simulation covering three orbital periods, we analyse the impact of turbulence with a particular focus on short-term and orbit-to-orbit variations. Methods. Our model uses a relativistic hydrodynamics description of the wind interaction in the LS-5039 system assuming a pulsar-wind driven scenario. The corresponding system of equations is solved using the finite-volume code Cronos. We compute statistical quantities, also relevant for particle acceleration in this system, from results of multiple consecutive timesteps. Results. In our simulation we find the previously observed shock structures related to the wind-collision region (WCR), including the pulsar-wind termination, being dynamically influenced by orbital motion. In our high-resolution simulation we find high turbulence levels following from instabilities driven at the WCR. These instabilities lead to strong fluctuations of several dynamical quantities especially around and after apastron. These fluctuations are expected to impact the particle transport and also especially the related emission of non-thermal radiation. As an important example, the region from which gamma-ray emission has been found to be boosted due to relativistic beaming in previous studies shows strong variations in size both on short and on orbital timescales. Conclusions. Using a large computational domain together with high spatial resolution allowed a detailed study of fluctuations in the stellar- and pulsar-wind interaction. The results indicate a possible influence on the non-thermal emission from this system, which will be analysed with dedicated simulations in a forthcoming publication.

Massive stars expel large amounts of mass during their late evolutionary phases. We aim to unveil the physical conditions within the warm molecular environments of B[e] supergiants (B[e]SGs) and yellow hypergiants (YHGs), which are known to be embedded in circumstellar shells and disks. We present K-band spectra of two B[e]SGs from the Large Magellanic Cloud and four Galactic YHGs. The CO band emission detected from the B[e]SGs LHA 120-S 12 and LHA 120-S 134 suggests that these stars are surrounded by stable rotating molecular rings. The spectra of the YHGs display a rather diverse appearance. The objects 6 Cas and V509 Cas lack any molecular features. The star [FMR2006] 15 displays blue-shifted CO bands in emission, which might be explained by a possible close to pole-on oriented bipolar outflow. In contrast, HD 179821 shows blue-shifted CO bands in absorption. While the star itself is too hot to form molecules in its outer atmosphere, we propose that it might have experienced a recent outburst. We speculate that we currently can only see the approaching part of the expelled matter because the star itself might still block the receding parts of a (possibly) expanding gas shell.

The climate of a terrestrial exoplanet is controlled by the type of host star, the orbital configuration and the characteristics of the atmosphere and the surface. Many rocky exoplanets have higher eccentricities than those in the Solar System, and about 18% of planets with masses $< 10 \mathrm{M}_{\oplus}$ have $e>0.1$. Underexplored are the implications of such high eccentricities on the atmosphere, climate, and potential habitability on such planets. We use WACCM6, a state-of-the-art fully-coupled Earth-system model, to simulate the climates of two Earth-like planets; one in a circular orbit ($e=0$), and one in an eccentric orbit ($e=0.4$) with the same mean insolation. We quantify the effects of eccentricity on the atmospheric water abundance and loss given the importance of liquid water for habitability. The asymmetric temperature response in the eccentric orbit results in a water vapour mixing ratio in the stratosphere ($> 20$ ppmv) that is approximately five times greater than that for circular orbit ($\sim 4$ ppmv). This leads to at most $\sim 3$ times increases in both the atmospheric hydrogen loss rate and the ocean loss rate compared with the circular case. Using the Planetary Spectrum Generator, we simulate the idealised transmission spectra for both cases. We find that the water absorption features are stronger at all wavelengths for the $e=0.4$ spectrum than for the circular case. Hence, highly-eccentric Earth-like exoplanets may be prime targets for future transmission spectroscopy observations to confirm, or otherwise, the presence of atmospheric water vapour.

After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701$-$462 turned on again in September 2022, allowing for the first study of its X-ray polarimetric characteristics by a dedicated observing program with the Imaging X-ray Polarimeter Explorer (IXPE). Polarimetric studies of XTE J1701$-$462 have been expected to improve our understanding of accreting weakly magnetized neutron stars, in particular, the physics and the geometry of the hot inner regions close to the compact object. The IXPE data of two triggered observations were analyzed using time-resolved spectroscopic and polarimetric techniques, following the source along its Z-track of the color-color diagram. During the first pointing on 2022 September 29, an average 2-8 keV polarization degree of 4.6$\pm$ 0.4\% was measured, the highest value found up to now for this class of sources. Conversely, only a $\sim$0.6\% average degree was obtained during the second pointing ten days later. The polarimetric signal appears to be strictly related to the higher energy blackbody component associated with the boundary layer (BL) emission and its reflection from the inner accretion disk, and it is as strong as 6.1\% and 1.2\% ($>95\%$ significant) above 3-4 keV for the two measurements, respectively. The variable polarimetric signal is apparently related to the spectral characteristics of XTE J1701$-$462, which is the strongest when the source was in the horizontal branch of its Z-track and the weakest in the normal branch. These IXPE results provide new important observational constraints on the physical models and geometry of the Z-sources. Here, we discuss the possible reasons for the presence of strong and variable polarization among these sources.

Aims. Our goal is the characterization of the hot ejecta and shocked interstellar medium (ISM) associated to the Vela supernova remnant (SNR), as well as the relativistic electrons injected into the ambient medium by its central pulsar. To achieve this, we analyze the X-ray data set of Vela acquired by SRG/eROSITA during its first four all-sky surveys. Methods. Apart from multi-band imaging, a quantitative view of the physical parameters affecting the observed thermal and non-thermal emission is obtained by performing spatially resolved X-ray spectroscopy of over 500 independent regions using multi-component spectral models. Results. Imaging demonstrates that the X-ray emission of the Vela SNR consists of at least three morphologically distinct components, with shell-like structures dominating below 0.6 keV, radial outward-directed features becoming apparent at medium energies, and the pulsar wind nebula (PWN) dominating the hard emission above 1.4 keV. Our spectroscopy reveals a highly structured distribution of X-ray absorption column densities, which intriguingly appears anticorrelated with optical extinction measurements. We find evidence for multiple ejecta clumps inside and outside the shell, within which we find a strongly supersolar concentration of neon and magnesium relative to oxygen. This includes the bright shrapnel D, in which we separate shocked ISM in the soft bow-shock from a hot, ejecta-rich clump at its apex, based on the new data. Finally, we find an extremely extended, smoothly decreasing distribution of synchrotron emission from the PWN, which extends up to 14 pc from the pulsar, with a total X-ray luminosity of $1.5\times10^{-3}$ of the pulsar's spin-down power. The extended emission likely traces a relativistic electron population in an ISM-level magnetic field, which requires the existence of a TeV counterpart powered by inverse Compton radiation.

Stars can be either disrupted as tidal disruption events (TDEs) or swallowed as a whole by massive black holes (MBHs) at galactic centers when they approach sufficiently close to these MBHs. In this work, we investigate the correlations of such stellar consumption rates with both the MBH mass $M_{\rm bh}$ and the inner slope of the host galaxy mass density distribution $\alpha$. We introduce a simplified analytical power-law model with a power-law stellar mass density distribution surrounding MBHs and separate the contributions of two-body relaxation and stellar orbital precession for the stellar orbital angular momentum evolution in nonspherical galaxy potentials. The stellar consumption rates derived from this simplified model can be well consistent with the numerical results obtained with a more realistic treatment of stellar distributions and dynamics around MBHs, providing an efficient way to estimate TDE rates. The origin of the correlations of stellar consumption rates with $M_{\rm bh}$ and $\alpha$ are explained by the dependence of this analytical model on those MBH/host galaxy properties and by the separation of the stellar angular momentum evolution mechanisms. We propose that the strong positive correlation between the rates of stellar consumption due to two-body relaxation and $\alpha$ provides one interpretation for the overrepresentation of TDEs found in some rare E+A/poststarburst galaxies. We find high TDE rates for giant stars, up to those for solar-type stars. The understanding of the origin of the correlations of the stellar consumption rates will be necessary for obtaining the demographics of MBHs and their host galaxies via TDEs.

Pulsar timing arrays (PTAs) are anticipated to detect the stochastic gravitational wave background (GWB) from supermassive binary black holes (BBHs) as well as the gravitational waves from individual BBHs. Recently, a common process signal was reported by several PTAs. In this paper, we investigate the constraints on the BBH population model(s) by current PTA observations and further study the detections of both the GWB and individual BBHs by current/future PTAs. We find that the MBH--host galaxy scaling relation, an important ingredient of the BBH population model, is required to either evolve significantly with redshift or have a normalization $\sim0.86-1.1$ dex higher than the empirical ones, if the GWB is the same as the common process signal. For both cases, the estimated detection probability for individual BBHs is too small for a positive detection by current PTAs. By involving either the constrained scaling relations or those empirical ones into the BBH population models, we estimate that the GWB may be detected with a signal-to-noise ratio $\gtrsim3$ by the PTAs based on the Five hundred meter Aperture Spherical radio Telescope (CPTA) and the Square Kilometer Array (SKAPTA) after $\sim2-3$ (or $\sim6-11$) years' observation, if it is the same as (or an order of magnitude lower than) the common process signal. The detection time of individual BBHs by CPTA and SKAPTA is close to that of the GWB detection. We show that the BBH population model can be strongly constrained by the number and property distributions of BBHs to be detected by future PTAs.

The AMS02 collaboration has recently published high precision daily measurements of the spectra of cosmic ray protons, helium nuclei and electrons taken during a time interval of approximately 10 years from 2011 to 2020. Positron spectra averaged over distinct 27 days intervals have also been made public. The AMS02 collaboration has shown some intriguing "hysteresis" effects observed comparing the fluxes of protons and helium nuclei or protons and electrons. In this work we address the question of the origin of these effects. We find that the spectral distortions generated by propagation in the heliosphere are significantly different for particles with electric charge of opposite sign (an effect already well established), with different behaviour before and after the solar magnetic field polarity reversal at solar maximum. This results in hysteresis effects for the p/e comparison that follow the 22-year solar cycle. On the other hand particles with electric charge of the same sign suffer modulations that are approximately equal. The hysteresis effects observed for a helium/proton comparison can then be understood as the consequence of the fact that the two particles have interstellar spectra of different shape, and the approximately equal spectral distortions generated by propagation in the heliosphere have a rigidity dependence that is a function of time. These hysteresis effects can in fact be observed studying the time dependence of the shape of the spectra of a single particle type, and also generate short time loop-like structures in the hysteresis curves correlated with large solar activity events such as CME's. A description of solar modulations that includes these effects must go beyond the simple Force Field Approximation (FFA) model. A minimal, two-parameter generalization of the FFA model that gives a good description of the observations is presented.

Galaxies usually reside in groups and clusters where they interact gravitationally. These interactions affect the internal dynamics of the galaxies. In this thesis, we have studied the effect of flyby interactions and dark matter distributions on the evolution of bulges and disks of spiral galaxies. To understand the effect of flyby interactions on the bulges, disks, and spiral arms of Milky Way mass galaxies, we simulated disk galaxies with classical bulges and boxy/peanut pseudo-bulges, then performed their flyby interactions with 1/10 and 1/5 mass galaxies. Using photometric and kinematic bulge-disk decompositions of the major galaxy, we showed that the disks get shorter and thicker during flyby interactions. Classical bulges remain intact. However, pseudo-bulges become dynamically hotter. Tidally induced spiral arms are transient density waves. They form soon after pericenter passage and decay in two phases; the initial rapid winding and the subsequent slow winding. We showed that the spirals are the main drivers of wave-like vertical breathing motion seen in the Milky Way. Tidal interactions do not directly induce breathing motion. In another work, we showed that the oblate dark matter halos delay bar formation, so bar buckling is also delayed, but probate halos promote multiple bucklings. Due to multiple bucklings, boxy/peanut bulges in prolate halos show the maximum thickness. Using SDSS galaxies, we found that pseudo-bulges are diffuse compared to classical bulges and are commonly found in low mass galaxies. In the local volume, pseudo-bulges overcome the classical bulges even in bulge dominated galaxies, so more than $75\%$ of local volume is rotation dominated. Finally, we showed that bulgeless galaxies in Illustris TNG50 are metal-poor, have high specific angular momentum as compared to the galaxies with bulges and fall at the lower end of baryonic to dark matter mass ratio.

Recently, we have uncovered Hidden Cooling Flows (HCF) in the X-ray spectra of the central Brightest Galaxies of 11 clusters, 1 group and 2 elliptical galaxies. Here we report such flows in a further 15 objects, consisting of 8 clusters, 3 groups, 3 ellipticals and 1 Red Nugget. The mass cooling rates are about 1 Msun/yr in the ellipticals, 2 to 20 Msun/yr in the groups and 20 to 100 Msun/yr in regular clusters. The Red Nugget, MRK1216, has an HCF of 10 Msun/yr. We review the fate of the cooled gas and investigate how some of it might accrete onto the central black hole. The gas is likely to be very cold and to have fragmented into low mass stars and smaller objects before being swallowed whole, with little luminous output. If such a scenario is correct and operates at a few Msun/yr then such objects may host the fastest growing black holes in the low redshift Universe. We briefly discuss the relevance of HCF to the growth of early galaxies and black holes.

We present a new semi-analytic formalism for modeling metal absorption lines that emerge from a clumpy galactic environment, ALPACA. We predict the ''down-the-barrel'' (DTB) metal absorption line profiles and the EW of absorption at different impact parameters as a function of the properties of the clumps, including the clump kinematics, the clump volume filling factor, the clump number density profile and the clump ion column densities. With ALPACA, we jointly model the stacked DTB CII$\lambda$1334 spectrum of a sample of $z \sim$ 3 Lyman break galaxies and the EW v.s. $b$ profile of a sample of $z \sim$ 2 star-forming galaxy-galaxy pairs. ALPACA successfully reproduced two datasets simultaneously, and the best-fit prefers a low clump volume filling factor ($\sim 3 \times 10^{-3}$). The radial velocities of the clumps are a superposition of a rapidly accelerated outflow with a maximum velocity of $\sim 400\,\rm km\,s^{-1}$ and a velocity dispersion of $\sigma_{\rm cl} \sim\,120 \rm km\,s^{-1}$. The joint modeling reveals a physical scenario where the absorption observed at a particular velocity is contributed by the clumps distributed over a fairly broad range of radii. We also find that the commonly adopted Sobolev approximation is at best only applicable within a narrow range of radii where the clumps are undergoing rapid acceleration in a non-volume-filling clumpy medium. Lastly, we find that the clump radial velocity profile may not be fully constrained by the joint modeling and spatially-resolved Ly$\alpha$ emission modeling may help break the degeneracy.

Using VLT/MUSE integral-field spectroscopic data for the barred spiral galaxy NGC 1097, we explore techniques that can be used to search for extended coherent shocks that can drive gas inflows in centres of galaxies. Such shocks should appear as coherent velocity jumps in gas kinematic maps, but this appearance can be distorted by inaccurate extraction of the velocity values and dominated by the global rotational flow and local perturbations like stellar outflows. We include multiple components in the emission-line fits, which corrects the extracted velocity values and reveals emission associated with AGN outflows. We show that removal of the global rotational flow by subtracting the circular velocity of a fitted flat disk can produce artefacts that obscure signatures of the shocks in the residual velocities if the inner part of the disk is warped or if gas is moving around the centre on elongated (non-circular) trajectories. As an alternative, we propose a model-independent method which examines differences in the LOSVD moments of H$\alpha$ and [N II]$\lambda$6583. This new method successfully reveals the presence of continuous shocks in the regions inward from the nuclear ring of NGC 1097, in agreement with nuclear spiral models.

We study the intensity, the modulation depth and the mean modulation depth of the gyrosynchrotron (GS) radiation as a function of the frequency and the line of sight (LOS) in fast sausage modes. By solving the 2.5D MHD ideal equations of a straight coronal loop considering the chromosphere and with typical flaring plasma parameters we analyse the wavelet transform of the density and the GS emission for different radio frequencies and different spatial resolutions, given impulsive and general perturbations with energies in the microflare range. A wavelet analysis performed over the GS radiation emission showed that a fast fundamental sausage mode of 7s with a first harmonic mode of 3s developed, for all the initial energy perturbations used. For both the high spatial resolution (central pixel integration) and the low spatial resolution (entire loop integration), the larger the radio frequency, the larger the modulation depth. However, high and low resolution integrations differ in that, the larger the LOS angle with respect to the loop axis, results in a larger and smaller modulation depth, respectively. Fast MHD modes triggered by instantaneous energy depositions of the order of a microflare energy are able to reproduce deep intensity modulation depths in radio emission as observed in solar events. As the trends of the GS emission obtained by Reznikova, Antolin, and Van Doorsselaere (2014), for a linear and forced oscillation, remain present when analysing a more general context, considering the chromosphere and where the sausage mode is triggered by a impulsive, nonlinear perturbation, it seems that the behaviour found can be used as observational identifiers of the presence of sausage modes with respect to other quasi-periodic pulsation features. It can be inferred from this that finite-amplitude sausage modes have the potential to generate the observed deep modulation depths.

We investigate whether triggering of the magnetorotational instability (MRI) in protoplanetary discs can account for the wide diversity of observed accretion outbursts. We show that short-lived, relatively low accretion rate events probably result from triggering in the inner disc and can occur at low surface densities, comparable to or smaller than the minimum mass solar nebula, and thus are very unlikely to result from MRI triggering by gravitational instability. We develop time-dependent accretion disc models using an $\alpha$-viscosity approach and calculate light curves to compare with observations. Our modeling indicates that the lag time between infrared and optical bursts seen in Gaia 17bpi can be explained with an outside-in propagation with an $\alpha \sim 0.1$ in the MRI-active region, consistent with other estimates. While outbursts in inner discs can show time delays of a few years between infrared and optical light curves, our models indicate that large, FU Ori-like bursts can exhibit infrared precursors decades before optical bursts. Detecting such precursors could enable analysis of the central star before it is overwhelmed by the rapid accreting material, as well as constraining outburst physics. Our results emphasize the importance of near-infrared monitoring of young stellar objects in addition to optical surveys. In addition, our findings emphasize the need for more sophisticated, three-dimensional, non-ideal magnetohydrodynamic simulations to fully exploit observational results.

Aims: Establish the dependence of variability properties, such as characteristic timescales t_b, on black hole mass and accretion rate, controlling for the restframe wavelength of emission. Methods: We selected the g-band light curves for 4770 objects from the Zwicky Transient Facility archive. All selected objects fall into a narrow redshift bin, 0.6<z<0.7, but cover a wide range of accretion rates in Eddington units (REdd) and black hole masses (M). We grouped these objects into 26 bins according to these parameters, calculated low-resolution g-band variability power spectra, and approximated the power spectra with a simple analytic model that features a break at a timescale t_b. Results: We found a clear dependence of t_b on REdd, on top of the known dependence of t_b on M. In our fits, $t_b\propto M^{0.65 - 0.55} REdd^{0.35 - 0.3}$, where the ranges in the exponents correspond to the best-fitting parameters of different powerspectral models. This mass dependence is slightly steeper than found in other studies. Scaling t_b to the orbital timescale of the ISCO, t_ISCO, results approximately in $t_b/t_{ISCO} \propto (REdd/M)^{0.35}$. In the standard thin disk model, $(REdd/M)\propto T_{max}^4$, where T_max is the maximum disk temperature, so that t_b/t_ISCO appears to scale approximately with the maximum temperature of the disc to a small power. The observed values of t_b are about 10 times the orbital timescale at the light-weighted average radius of the disc region emitting in the (observer frame) g-band. The different scaling of the break frequency with M and REdd shows that the shape of the variability power spectrum cannot be solely a function of the quasar luminosity, even for a single rest-frame wavelength. Finally, the best-fitting models have slopes above the break of -2.5 or -3. A slope of -2, as in the damped random walk models, fits the data significantly worse.

We present the volumetric rates and luminosity functions (LFs) of Type Ia supernovae (SNe Ia) from the $V$-band All-Sky Automated Survey for Supernovae (ASAS-SN) catalogues spanning discovery dates from UTC 2014-01-26 to UTC 2017-12-29. Our standard sample consists of 404 SNe Ia with $m_{V,\mathrm{peak}}<17$ mag and Galactic latitude $|b|>15^{\circ}$. Our results are both statistically more precise and systematically more robust than previous studies due to the large sample size and high spectroscopic completeness. We make completeness corrections based on both the apparent and absolute magnitudes by simulating the detection of SNe Ia in ASAS-SN light curves. We find a total volumetric rate for all sub-types of $R_{\mathrm{tot}}=2.28^{+0.20}_{-0.20}\,\times 10^{4}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$ for $M_{V,\mathrm{peak}}<-16.5$ mag ($R_{\mathrm{tot}}=1.91^{+0.12}_{-0.12}\,\times 10^{4}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$ for $M_{V,\mathrm{peak}}<-17.5$ mag) at the median redshift of our sample, $z_{\mathrm{med}}=0.024$. This is in agreement ($1\sigma$) with the local volumetric rates found by previous studies. We also compile luminosity functions (LFs) for the entire sample as well as for sub-types of SNe Ia for the first time. The major sub-types with more than one SN include Ia-91bg, Ia-91T, Ia-CSM, and Ia-03fg with total rates of $R_{\mathrm{Ia-91bg}}=1.4^{+0.5}_{-0.5} \times 10^{3}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$, $R_{\mathrm{Ia-91T}}=8.5^{+1.6}_{-1.7} \times 10^{2}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$, $R_{\mathrm{Ia-CSM}}=10^{+7}_{-7}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$, and $R_{\mathrm{Ia-03fg}}=30^{+20}_{-20}\,\mathrm{yr}^{-1}\,\mathrm{Gpc}^{-3}\,h^{3}_{70}$, respectively. We estimate a mean host extinction of $E(V-r)\approx 0.2$ mag based on the shift between our $V$-band and the ZTF $r$-band LFs.

In previous works (Wang et al. 2020, 2022), we proposed to estimate cosmological parameters with the artificial neural network (ANN) and the mixture density network (MDN). In this work, we propose an improved method called the mixture neural network (MNN) to achieve parameter estimation by combining ANN and MDN, which can overcome shortcomings of the ANN and MDN methods. Besides, we propose sampling parameters in a hyper-ellipsoid for the generation of the training set, which makes the parameter estimation more efficient. A high-fidelity posterior distribution can be obtained using $\mathcal{O}(10^2)$ forward simulation samples. In addition, we develop a code-named ``CoLFI'' for parameter estimation, which incorporates the advantages of MNN, ANN, and MDN, and is suitable for any parameter estimation of complicated models in a wide range of scientific fields. CoLFI provides a more efficient way for parameter estimation, especially for cases where the likelihood function is intractable or cosmological models are complex and resource-consuming. It can learn the conditional probability density $p(\boldsymbol\theta|\boldsymbol{d})$ using samples generated by models, and the posterior distribution $p(\boldsymbol\theta|\boldsymbol{d}_0)$ can be obtained for a given observational data $\boldsymbol{d}_0$. We tested the MNN using power spectra of the cosmic microwave background and Type-Ia supernovae and obtained almost the same result as the Markov Chain Monte Carlo method. The numerical difference only exists at the level of $\mathcal{O}(10^{-2}\sigma)$. The method can be extended to higher dimensional data.

Recent works have proposed the idea of a tidal screening scenario, in which tidal forces determine the mass that a protostar can accrete to explain the IMF. In this scenario, gravitationally unstable fragments will compete for the gas reservoir in a star-forming clump. In this contribution, we propose to properly include the action of an external gravitational potential in the Jeans linear instability analysis as previously proposed by Jog. We have found that an external gravitational potential can reduce the critical mass required for the perturbation to collapse if the tidal force produced is compressive or increase it if it is disruptive. Our analytical treatment provides (a) new mass and length collapse conditions; (b) a simple equation for observers to check whether their observed fragments can collapse; and (c) a simple equation to compute whether collapse-induced turbulence can produce the levels of observed fragmentation. Our results suggest that, given envelopes with similar mass and density, the flatter ones should produce more stars than the steeper ones. If the density profile is a power-law, the corresponding power-law index separating these two regimes should be about 1.5. We finally applied our formalism to 160 fragments identified within 18 massive star-forming cores of previous works. We found that considering tides, 49% of the sample may be gravitationally unstable and that it is unlikely that turbulence acting at the moment of collapse has produced the fragmentation of these cores. Instead, these fragments should have formed earlier when the parent core was substantially flatter.

Dynamical instabilities among giant planets are thought to be nearly ubiquitous, and culminate in the ejection of one or more planets into interstellar space. Here we perform N-body simulations of dynamical instabilities while accounting for torques from the galactic tidal field. We find that a fraction of planets that would otherwise have been ejected are instead trapped on very wide orbits analogous to those of Oort cloud comets. The fraction of ejected planets that are trapped ranges from 1-10%, depending on the initial planetary mass distribution. The local galactic density has a modest effect on the trapping efficiency and the orbital radii of trapped planets. The majority of Oort cloud planets survive for Gyr timescales. Taking into account the demographics of exoplanets, we estimate that one in every 200-3000 stars could host an Oort cloud planet. This value is likely an overestimate, as we do not account for instabilities that take place at early enough times to be affected by their host stars' birth cluster, or planet stripping from passing stars. If the Solar System's dynamical instability happened after birth cluster dissolution, there is a ~7% chance that an ice giant was captured in the Sun's Oort cloud.

In the interstellar cold gas, the chemistry of formaldehyde (H$_2$CO) can be essential to explain the formation of complex organic molecules. On this matter, the massive and energetic protostellar object G331 is still unexplored and, hence, we carried out a comprehensive study of the isotopologues of H$_2$CO and formyl cation (HCO$^+$), and of protonated formaldehyde (H$_2$COH$^+$) through the APEX observations in the spectral window $\sim$159-356~GHz. We employed observational and theoretical methods to derive the physical properties of the molecular gas combining LTE and non-LTE analyses. Formaldehyde was characterized via 35 lines of H$_2$CO, H$_2^{13}$CO, HDCO and H$_2$C$^{18}$O. The formyl cation was detected via 8 lines of HCO$^+$, H$^{13}$CO$^+$, HC$^{18}$O$^+$ and HC$^{17}$O$^+$. Deuterium was clearly detected via HDCO, whereas DCO$^+$ remained undetected. H$_2$COH$^+$ was detected through 3 clean lines. According to the radiative analysis, formaldehyde appears to be embedded in a bulk gas with a wide range of temperatures ($T\sim$20-90 K), while HCO$^+$ and H$_2$COH$^+$ are primarily associated with a colder gas ($T\lesssim$ 30 K). The reaction H$_2$CO+HCO$^+ \rightarrow$ H$_2$COH$^+$ + CO is crucial for the balance of the three species. We used Nautilus gas-grain code to predict the evolution of their molecular abundances relative to H$_2$ which values at time scales $\sim$10$^3$ yr matched with the observations in G331: [H$_2$CO] = (0.2-2) $\times$10$^{-8}$, [HCO$^+$] = (0.5-4) $\times$10$^{-9}$ and [H$_2$COH$^+$] = (0.2-2) $\times$10$^{-10}$. Based on the molecular evolution of H$_2$CO, HCO$^+$ and H$_2$COH$^+$, we hypothesized about the young lifetime of G331, which is consistent with the active gas-grain chemistry of massive protostellar objects.

In this paper we present the development of a dataset consisting of 91 Multi-band Cloud and Moisture Product Full-Disk (MCMIPF) from the Advanced Baseline Imager (ABI) on board GOES-16 geostationary satellite with 91 temporally and spatially corresponding CLDCLASS products from the CloudSat polar satellite. The products are diurnal, corresponding to the months of January and February 2019 and were chosen such that the products from both satellites can be co-located over South America. The CLDCLASS product provides the cloud type observed for each of the orbit's steps and the GOES-16 multiband images contain pixels that can be co-located with these data. We develop an algorithm that returns a product in the form of a table that provides pixels from multiband images labelled with the type of cloud observed in them. These labelled data conformed in this particular structure are very useful to perform supervised learning. This was corroborated by training a simple linear artificial neural network based on the work of Gorooh et al. (2020), which gave good results, especially for the classification of deep convective clouds.

This work presents the properties of near-infrared (NIR) counterparts of eight ultraluminous X-ray sources (ULXs) in NGC 1672. Through advanced astrometry based on the Chandra and James Webb Space Telescope (JWST) observations, as well as the GAIA optical source catalog, unique NIR counterparts determined for four ULXs while multiple potential NIR counterparts for remaining four ULXs within the astrometric error radius of 0.38 arcsec. Possible scenarios for donor candidates of the two ULXs (ULX-5 and ULX-8) suggest that they could be either red supergiant (SRG) or red giant (RG) and also the counterpart of ULX-4 could be AGN or star cluster due to its high F200W ($-$12 mag). Thanks to the good enough resolution of the NIRCam images, most of the point-like and/or bright NIR counterparts of ULXs observed in past studies appear to be likely blended sources, so most likely, many of them do not have the enough of red color that an RSG could have. The significant improvement in sensitivity and resolution supplied by JWST will lead to a new perspective on the ambiguous nature of ULX donors, necessitating a significant reassessment of earlier infrared research into counterparts of ULXs. This study shows that the apparent magnitudes of the NIR counterparts look faint, just like optical counterparts ($<$18 mag). Moreover, this work presents that unique NIR counterparts of ULXs are ideal candidates for JWST Near-Infrared Spectrograph (NIRSpec) observations to constrain the nature of possible donor stars.

The structure and evolution of wind-blown bubbles (WBBs) around massive stars has primarily been investigated using an energy-conserving model of wind-blown bubbles. While this model is useful in explaining the general properties of the evolution, several problems remain, including inconsistencies between observed wind luminosities and those derived using this formulation. Major difficulties include the low X-ray temperature and X-ray luminosity, compared to the model. In this paper, we re-examine the evolution, dynamics, and kinematics of WBBs around massive stars, using published ionization gasdynamic simulations of wind-blown bubbles. We show that WBBs can cool efficiently due to the presence of various instabilities and turbulence within the bubble. The expansion of WBBs is more consistent with a momentum-conserving solution, rather than an energy-conserving solution. This compares well with the dynamics and kinematics of observed wind bubbles. Despite the cooling of the bubble, the shocked wind temperature is not reduced to the observed values. We argue that the X-ray emission arise mainly from clumps and filaments within the hot shocked wind region, with temperatures just above 10$^6$ K. The remainder of the plasma can contribute to a lesser extent.

We use the recent releases of sensitive VLA/LOFAR large-area surveys at 340 MHz and 54 MHz, in conjunction with the 1.4 GHz NVSS, to accurately determine the `spectral index - flux density relation' ($\alpha$ - S) for extragalactic radio sources selected at metre and decametre wavelengths, the latter for the first time. This newly determined $\alpha$ - S$_{\rm 340~MHz}$ relation shows a progressive flattening of $\alpha_{\rm median}$ towards lower flux densities, starting from its steepest value (peak)occurring near S$_{\rm 340~MHz}$ $\sim$ 1-2 Jy. This resolves the controversy extant in the literature since the 1980s. The $\alpha$ - S$_{\rm 54~MHz}$ relation, too, shows a spectral index flattening with decreasing flux density which, however, is significantly milder and the relation is less sharply peaked than that found at 340 MHz. A possible reason for the difference could be that the 54 MHz sample has a distinctly stronger/conspicuous presence ( at $\sim$ 20% level) of very steep spectrum sources having $\alpha_{54}^{1400} <$ -1.3, most of which are probably associated with clusters of galaxies.

We carried out deep mapping observations of the atomic hydrogen (HI) 21 cm line emission in a field centered on the famous galaxy group Stephan's Quintet (SQ), using the Five-hundred-meter Aperture Spherical Telescope (FAST) equipped with the 19-Beam Receiver. The final data cube reaches an HI column density sensitivity of $5 \sigma = 2.1\times 10^{17}$ cm$^{-2}$ per 20 km s$^{-1}$ channel with an angular resolution of $4'.0$. The discovery of a large diffuse feature of the HI emission in the outskirt of the intragroup medium of SQ was reported in a previous paper (Xu et al. 2022). Here we present a new study of the total HI emission of SQ and the detection of several neighboring galaxies, exploiting the high sensitivity and the large sky coverage of the FAST observations. A total HI mass of $M_{\rm HI} = 3.48 \pm 0.35 \times 10^{10}\; M_\odot$ is found for SQ, which is significantly higher than previous measurements in the literature. This indicates that, contrary to earlier claims, SQ is not HI deficient. The excessive HI gas is mainly found in the velocity ranges of 6200 - 6400 km s$^{-1}$ and 6800 - 7000 km s$^{-1}$, which was undetected in previous observations that are less sensitive than ours. Our results suggest that the ``missing HI" in compact groups may be hidden in the low-density diffuse neutral gas instead of in the ionized gas.

Cosmic rays are particles from the upper atmosphere which often leave bright spots and trails in images from telescope CCDs. We investigate so-called ``fat" cosmic rays seen in images from Vera C. Rubin Observatory and the Subaru Telescope. These tracks are much wider and brighter than typical cosmic ray tracks, and therefore are more capable of obscuring data in science images. By understanding the origins of these tracks, we can better ensure that they do not interfere with on-sky data. We compare the properties of these tracks to simulated and theoretical models in order to identify both the particles causing these tracks as well as the reason for their excess spread. We propose that the origin of these tracks is cosmic ray protons, which deposit much greater charge in the CCDs than typical cosmic rays due to their lower velocities. The generated charges then repel each other while drifting through the detector, resulting in a track which is much wider than typical tracks.

That jetted active galactic nuclei (AGN) are also hosted in spiral galaxies is now well established. Our understanding of how such objects might fit in the radio loud AGN subclass has been described by Foschini and others over the past decade in that jets in spirals are weaker than those of radio galaxies and quasars because the black holes in spirals tend to be less massive. Recent data, however, may be pointing to a different picture which we describe. Unlike powerful jetted AGN in ellipticals, we illustrate from model perspectives, features of jets in spirals responsible for limiting both their power as well as their effect on their host galaxies. AGN triggered by secular processes fail to generate jet re-orientation, a key ingredient in the jetted AGN feedback mechanism in merger-triggered ellipticals that leads to the red-and-dead radio galaxies at low redshift such as M87. As a result, jetted AGN in spirals tend to live in a separate part of the parameter space compared to radio galaxies and quasars. Because of the absence of jet reorientation and due to the relatively short-lived jet phases, jetted AGN in spirals are best compared to radio quiet or jetless AGN than any other jetted AGN subclass.

For over a decade there have been contradictory claims in the literature on whether the bulk flow motion of galaxies in our local region are consistent or in tension with the Lambda-CDM model. While it has been evident in the literature that various systematics affect bulk flow measurements, systematics in the estimators used have not been widely investigated. In this work, we thoroughly evaluate the performance of four bulk flow estimator variants, including the Kaiser maximum likelihood estimator (MLE) and the minimum variance estimator (MVE) by testing their performance on mock data. We find in agreement with previous results, that these estimators do generally give unbiased bulk flows, however the precision of these estimators may be strongly correlated with the survey geometry. Small biases in the estimators can be present that lead to underestimated bulk flows, which we suspect are due to the presence of non-linear peculiar motions. The uncertainty assigned to the bulk flows obtained from these estimators is also typically underestimated, which leads to an overestimate of the level of tension with the Lambda-CDM model. We estimate the bulk flow with these methods for the CosmicFlows-4 data after testing them on realistic mocks to ensure the uncertainties are appropriately accounted for. Using the MLE we find a bulk flow amplitude of $408 \pm 165 \mathrm{km s}^{-1}$ at a depth of $49\, \mathrm{Mpc} h^{-1}$, in reasonable agreement with Lambda-CDM. However using the MVE which can estimate the bulk flow at a greater effective depth, we find an amplitude of $428 \pm 108 \mathrm{km s}^{-1}$ at a depth of $173\, \mathrm{Mpc} h^{-1}$, in tension with the model, by having only a 0.11% probability of obtaining a larger $\chi^2$. Both of these measurements indicate the bulk flow is directed towards the Great Attractor region where more data may be needed to resolve bulk flow tensions.

This paper presents a new sample of 19 unique galaxies and galaxy groups at $z\approx1$ from the CUBS program, which is designated as the CUBSz1 sample. In this CUBSz1 sample, nine galaxies or galaxy groups show absorption features, while ten systems do not have detectable absorption with 2-$\sigma$ upper limits of log$N$(HeI)/cm$^{-2}\lesssim 13.5$ and log$N$(OV)/cm$^{-2}\lesssim 13.3$. Environmental properties of the galaxies, including galaxy overdensities, the total stellar mass and gravitational potential summed over all nearby neighbors, and the presence of local ionizing sources, are found to have a significant impact on the observed CGM absorption properties. Specifically, massive galaxies and galaxies in overdense regions exhibit a higher rate of incidence of absorption. At the same time, the observed CGM absorption properties in galaxy groups appear to be driven by the galaxy closest to the QSO sightline, rather than by the most massive galaxy or by mass-weighted properties. We introduce a total projected gravitational potential $\psi$, defined as $-\psi/G =\sum M_{{\rm halo}}/d_{{\rm proj}}$ summed over all group members, to characterize the overall galaxy environment. This projected gravitational potential correlates linearly with the maximum density detected in each sightline, consistent with higher-pressure gas being confined in deeper gravitational potential wells. In addition, we find that the radial profile of cool gas density exhibits a general decline from the inner regions to the outskirts, being in pressure balance with the hot halo. Finally, we note that the ionizing flux from nearby galaxies can generate an elevated $N$(HI)/$N$(HeI) ratio, which in turn provides a unique diagnostic of possible local sources contributing to the ionizing radiation field.

A growing number of Milky Way globular clusters have been identified to possess a noticeable degree of solid-body rotation. For several clusters, the combination of stellar proper motions and radial velocities allows for 3-dimensional spin axes to be extracted. In this paper we consider the orientations of these spin axes, and ask whether they are correlated with any other properties of the clusters -- either global properties to do with their orbits and origin, or internal properties related to the cluster composition. We discuss the possibility of alignments between the spin axes of globular clusters, chemodynamical groupings, and their orbital poles. We also point out a previously unidentified negative correlation between the measured gamma-ray emissivities and the inclination of the globular cluster spins with respect to the line of sight. Given that this correlation is not present in other wavelengths, we cannot conclusively attribute it solely to sampling bias. If the correlation holds up to scrutiny with more data, it may be indicative of sources of anisotropic gamma-ray emission in globular clusters. We discuss the plausibility of such an anisotropy arising from a population of dynamically formed millisecond pulsars with some degree of spin-orbit alignment.

To expand frontiers and achieve measurable progress, instruments such as hyperspectral imagers are increased in resolution, field of view, and spectral resolution and range, leading to dramatically higher data volumes. Increasingly, data need to be returned from greater distances, ranging from the Sun-earth L1/ L2 points at 1.5 million km, to L4/L5 halo orbits at 1 AU, to several AU in the case of planetary probes. Optical communications can significantly reduce resource competition, requiring significantly fewer passes per day and/or shorter overall passes, and thereby enable far greater, transformative science return from individual missions and the capacity to support multiple such missions within a smaller ground network. Optical communications also provides superior performance and increased ranges for Inter-satellite Links (ISL) from 2,000 to 10,000 km for Swarms and DSMs. Lastly, the only way to guarantee timely space weather warnings (with a target of 15 minutes latency) is through space relays in MEO or GEO orbits, a strategy which also includes optical communications.

Solar energetic particle (SEP) events are one of the most crucial aspects of space weather. Their prediction depends on various factors including the source solar eruptions such as flares and coronal mass ejections (CMEs). The Geostationary Solar Energetic Particle (GSEP) Events catalog was developed as an extensive data set towards this effort for solar cycles 22, 23 and 24. In the present work, we review and extend the GSEP data set by; (1) adding "weak" SEP events that have proton enhancements from 0.5 to 10 pfu in the E>10 MeV channel, and (2) improving the associated solar source eruptions information. We analyze and discuss spatio-temporal properties such as flare magnitudes, locations, rise times, and speed and width of CMEs. We check for the correlation of these parameters with peak proton fluxes and event fluences. Our study also focuses on understanding feature importance towards the optimal performance of machine learning (ML) models for SEP event forecasting. We implement random forest (RF), extreme gradient boosting (XGBoost), logistic regression (LR) and support vector machines (SVM) classifiers in a binary classification schema. Based on the evaluation of our best models, we find both the flare and CME parameters are requisites to predict the occurrence of an SEP event. This work is a foundation for our further efforts on SEP event forecasting using robust ML methods.

Perturbations to the cosmic baryon density - and thus to the total-matter density - can be induced by magnetohydronamic forces if there are primordial magnetic fields. The power spectrum for these density perturbations was first provided in 1996, but without much in the way of detail in the derivation, and there has been confusion in the intervening years about this calculation. In this brief note, we re-derive this power spectrum using modern conventions, provide a simplified result, and identify some of the discrepancies in the literature.

Near-Earth asteroids (NEAs) that may evolve into impactors deserve detailed threat assessment studies. Early physical characterization of a would-be impactor may help in optimizing impact mitigation plans. We first detected NEA 2023~DZ$_{2}$ on 27--February--2023. After that, it was found to have a Minimum Orbit Intersection Distance (MOID) with Earth of 0.00005~au as well as an unusually high initial probability of becoming a near-term (in 2026) impactor. We aim to perform a rapid but consistent dynamical and physical characterization of 2023~DZ$_{2}$ as an example of a key response to mitigate the consequences of a potential impact. We use a multi-pronged approach, drawing from various methods (observational/computational) and techniques (spectroscopy/photometry from multiple instruments), and bringing the data together to perform a rapid and robust threat assessment.} The visible reflectance spectrum of 2023~DZ$_{2}$ is consistent with that of an X-type asteroid. Light curves of this object obtained on two different nights give a rotation period $P$=6.2743$\pm$0.0005 min with an amplitude $A$=0.57$\pm$0.14~mag. We confirm that although its MOID is among the smallest known, 2023~DZ$_{2}$ will not impact Earth in the foreseeable future as a result of secular near-resonant behaviour. Our investigation shows that coordinated observation and interpretation of disparate data provides a robust approach from discovery to threat assessment when a virtual impactor is identified. We prove that critical information can be obtained within a few days after the announcement of the potential impactor.

The mass and distribution of metals in the interiors of exoplanets are essential for constraining their formation and evolution processes. Nevertheless, with only masses and radii measured, the determination of exoplanet interior structures is degenerate, and so far simplified assumptions have mostly been used to derive planetary metallicities. In this work, we present a method based on a state-of-the-art interior code, recently used for Jupiter, and a Bayesian framework, to explore the possibility of retrieving the interior structure of exoplanets. We use masses, radii, equilibrium temperatures, and measured atmospheric metallicities to retrieve planetary bulk metallicities and core masses. Following results on the giant planets in the solar system and recent development in planet formation, we implement two interior structure models: one with a homogeneous envelope and one with an inhomogeneous one. Our method is first evaluated using a test planet and then applied to a sample of 37 giant exoplanets with observed atmospheric metallicities from the pre-JWST era. Although neither internal structure model is preferred with the current data, it is possible to obtain information on the interior properties of the planets, such as the core mass, through atmospheric measurements in both cases. We present updated metal mass fractions, in agreement with recent results on giant planets in the solar system.

We explore experimentally possible explanations of the polarization curves of the sunlight reflected by the Barbarian asteroids. Their peculiar polarization curves are characterized by a large inversion angle, around 30 degrees, which could be related to the presence of FeO-bearing spinel embedded in Calcium-Aluminum Inclusions. In order to test this hypothesis, we have measured the phase function and degree of linear polarization of six samples of Mg-rich olivine and spinel. For each material, we have analyzed the light scattering properties of a millimeter-sized grain and of two powdered samples with size distributions in the micrometer size range. The three spinel samples show a well-defined negative polarization branch with an inversion phase angle located around 24-30 degrees. In contrast, in the case of the olivine samples, the inversion angle is highly dependent on particle size and tends to decrease for larger sizes. We identify the macroscopic geometries as a possible explanation for the evident differences in the polarization curves between olivine and spinel millimeter samples. Although the polarization behaviour in near backscattering of the Barbara asteroid is similar to that of our spinel mm-sized sample in random orientation, this similarity could result in part from crystal retro-reflection rather than composition. This is part of an ongoing experimental project devoted to test separately several components of CV3-like meteorites, representative of the Barbarians composition, to disentangle their contributions to the polarization behavior of these objects.

Many in situ potassium-argon (K-Ar) dating instruments under development use laser ablation to perform local analyses of several hundred um on rocks. Laser-induced breakdown spectroscopy (LIBS) and noble gas mass spectrometry (MS) are combined to achieve multiple spot analyses of the same rock to obtain K-Ar isochrons. The range and error of the data points on an isochron determine the accuracy and precision of dating. The range of the data on the isochron is governed by the relationship between the laser spot size and mineral size in the target rocks. A smaller laser spot size increases the range of the measured K concentration but decreases the amount of Ar extracted, which deteriorates the measurement accuracy. Because of this trade-off, the optimal laser spot size, which would give the best dating accuracy, would be somewhere in the middle. The mineral composition and spatial distribution in Martian rocks determine this optimum spot size. However, no extensive studies have been conducted to consider optimum laser spot size taking the mineral compositions of Martian rocks into account. Thus, it has been unknown how accurate the LIBS-MS method can be for in situ dating on Mars. In this study, we quantify the precision of dating Martian rocks by the LIBS-MS method and determine the instrumental conditions necessary for achieving the required precision. The dating precision was quantitatively evaluated by simulating isochrons that reflect the mineral composition of Martian rocks, which were obtained with electron probe microanalysis of three Martian meteorites. Our results indicate that a dating precision of 200 Myr could be achieved by reducing the laser spot size to 250 um and improving the measurement accuracy of K and Ar concentrations to 10%. We determined the instrumental conditions necessary to achieve the required dating precision for the LIBS-MS instrument currently developing.

The $\gamma$-process nucleosynthesis in core-collapse supernovae is generally accepted as a feasible process for the synthesis of neutron-deficient isotopes beyond iron. However, crucial discrepancies between theory and observations still exist: the average production of $\gamma$-process yields from massive stars are too low to reproduce the solar distribution in galactic chemical evolution calculations, and the yields of the Mo and Ru isotopes are by a further factor of 10 lower than the yields of the other $\gamma$-process nuclei. We investigate the $\gamma$-process in 5 sets of core-collapse supernova models published in literature with initial masses 15, 20, and 25 M$_{\odot}$ at solar metallicity. We compared the $\gamma$-process overproduction factors from the different models. To highlight the possible effect of nuclear physics input, we also considered 23 ratios of two isotopes close to each other in mass, relative to their solar values. Further, we investigated the contribution of C-O shell mergers in the supernova progenitors as an additional site of the $\gamma$-process. Our analysis shows that a large scatter among the different models exists for both the $\gamma$-process integrated yields and the isotopic ratios. We found only 10 ratios that agree with their solar values, all the others differ by at least a factor of 3 from the solar values in all the considered sets of models. The $\gamma$-process within C-O shell mergers mostly influence the isotopic ratios that involve intermediate and heavy proton-rich isotopes with $\rm A>100$.

We present a proof-of-principle determination of the Hubble parameter $H(z)$ from photometric data, obtaining a determination at an effective redshift of $z=0.75$ ($0.65<z<0.85$) of $H(0.75) =105.0\pm 7.9(stat)\pm 7.3(sys)$ km s$^{-1}$ Mpc$^{-1}$, with 7.5\% statistical and 7\% systematic (10\% with statistical and systematics combined in quadrature) accuracy. This is obtained in a cosmology model-independent fashion, but assuming a linear age-redshift relation in the relevant redshift range, as such, it can be used to constrain arbitrary cosmologies as long as $H(z)$ can be considered slowly varying over redshift. In particular, we have applied a neural network, trained on a well-studied spectroscopic sample of 140 objects, to the {\tt COSMOS2015} survey to construct a set of 19 thousand near-passively evolving galaxies and build an age-redshift relation. The Hubble parameter is given by the derivative of the red envelope of the age-redshift relation. This is the first time the Hubble parameter is determined from photometry at $\lesssim 10$\% accuracy. Accurate $H(z)$ determinations could help shed light on the Hubble tension; this study shows that photometry, with a reduction of only a factor of two in the uncertainty, could provide a new perspective on the tension.

Without mitigation, the intrinsic alignment (IA) of galaxies poses a significant threat to achieving unbiased cosmological parameter constraints from precision weak lensing surveys. Here, we apply for the first time to data a method to extract the scale dependence of the IA contribution to galaxy-galaxy lensing, which takes advantage of the difference in alignment signal as measured by shear estimators with different sensitivities to galactic radii. Using data from Year 1 of the Dark Energy Survey, with shear estimators METCALIBRATION and IM3SHAPE, we find that systematic uncertainties dominate our signal and claiming a detection of IA is not possible. In particular, uncertainty on multiplicative bias calibration poses a significant challenge. Building upon this, we forecast the application of this method to Rubin Observatory Legacy Survey of Space and Time (LSST) data. We develop a scheme to account for residual multiplicative bias within the measurement covariance, and forecast the requirements on a pair of shear estimators for detecting IA and constraining its 1-halo scale dependence. We find that for LSST Year 1, shear estimators should have at least a $40\%$ difference in IA amplitude, and the Pearson correlation coefficient of their shape noise should be at least $\rho=0.50$, to ensure a $1\sigma$ detection of IA and a constraint on its 1-halo scale dependence with a signal-to-noise ratio greater than $1$. For Year 10, a $1\sigma$ detection and constraint become possible for $20\%$ differences in alignment amplitude and $\rho=0.50$.

Swift J1749.4-2807 is the only known eclipsing accreting millisecond X-ray pulsar. In this paper, we report on 7 thermonuclear (Type-I) X-ray bursts observed by NICER during its 2021 outburst. The first 6 bursts show slow rises and long decays, indicative of mixed H/He fuel, whereas the last burst shows fast rise and decay, suggesting He-rich fuel. Time-resolved spectroscopy of the bursts revealed typical phenomenology (i.e., an increase in black body temperature during the burst rise, and steady decrease in the decay), however they required a variable $N_\mathrm{H}$. We found that the values of $N_\mathrm{H}$ during the bursts were roughly double those found in the fits of the persistent emission prior to each burst. We interpret this change in absorption as evidence of burst-disc interaction, which we observe due to the high inclination of the system. We searched for burst oscillations during each burst and detected a signal in the first burst at the known spin frequency of the neutron star (517.92 Hz). This is the first time burst oscillations have been detected from Swift J1749.4-2807. We further find that each X-ray burst occurs on top of an elevated persistent count rate. We performed time-resolved spectroscopy on the combined data of the bursts with sufficient statistics (i.e., the clearest examples of this phenomenon) and found that the black body parameters evolve to hotter temperatures closer to the onset of the bursts. We interpret this as a consequence of an unusual marginally stable burning process similar to that seen through mHz QPOs.

This work presents the magnetic field geometry in a complex of three cometary (with head-tail morphology) globules, namely LDN 323, LDN 328, and LDN 331, using R-band polarization measurements of background stars. These observations were combined with a Planck sky survey to study the large-scale morphology of the magnetic fields in the region. The distances of the target stars were adopted from the Gaia catalog. The variation of degree of polarization and polarization position angle with distances of stars is analyzed. The field geometry is mostly found to follow the cometary shape of the cloud, with some randomness at certain locations. For studying the correlation between cloud morphology and magnetic field orientations, a modified version of the Histogram of Relative Orientation analysis was employed.

In this study, we investigate the impact of microlensing on gravitational wave (GW) signals in the LIGO$-$Virgo sensitivity band. Microlensing caused by an isolated point lens, with (redshifted) mass ranging from $M_\mathrm{Lz}\in(1,10^5){\rm M}_\odot$ and impact parameter $y\in (0.01,~5)$, can result in a maximum mismatch of $\sim 30\%$ with their unlensed counterparts. When $y<1$, it strongly anti-correlates with the luminosity distance enhancing the detection horizon and signal-to-noise ratio (SNR). Biases in inferred source parameters are assessed, with in-plane spin components being the most affected intrinsic parameters. The luminosity distance is often underestimated, while sky-localisation and trigger times are mostly well-recovered. Study of a population of microlensed signals due to an isolated point lens primarily reveals: (i) using unlensed templates during the search causes fractional loss ($20\%$ to $30\%$) of potentially identifiable microlensed signals; (ii) the observed distribution of $y$ challenges the notion of its high improbability at low values ($y\lesssim 1$), especially for $y\lesssim 0.1$; (iii) Bayes factor analysis of the population indicates that certain region in $M_\mathrm{Lz}-y$ parameter space have a higher probability of being detected and accurately identified as microlensed. Notably, the microlens parameters for the most compelling candidate identified in previous microlensing searches, GW200208_130117, fall within a 1-sigma range of the aforementioned higher probability region. Identifying microlensing signatures from $M_\mathrm{Lz}<100~$M$_\odot$ remains challenging due to small microlensing effects at typical SNR values. Additionally, we also examined how microlensing from a population of microlenses influences the detection of strong lensing signatures in pairs of GW events, particularly in the posterior-overlap analysis.

Neutron stars are known to be efficient accelerators producing particles with ultra-relavistic energies. As a by product they also emit copiously photons from radio wavelengths up to gamma-rays. As a follow up of our previous work on particle acceleration simulation near neutron stars, in this paper, we discuss the impact of radiation reaction on test particles injected into their magnetosphere. We therefore neglect the interaction between particles through the electromagnetic field as well as gravitation. We found that while due solely to the Lorentz force electrons reach Lorentz factors up to $\gamma=10^{14}$ and protons up to $\gamma=10^{10.7}$, when radiation reaction is enabled electrons reach energies up to $\gamma=10^{10.5}$ and protons up to $\gamma=10^{8.3}$. The latter values are more realistic since the radiation reaction feedback is predominant within the magnetosphere. Moreover, as expected, symmetrical behaviours between the north and the south hemispheres is highlighted, either with respect to the location around the neutron star or with respect to particles of opposite charge to mass ratio~$q/m$. Consequently, it is useless to simulate the full set of geometrical parameters to get an overview of all possibilities. The study of the influence of the magnetic dipolar moment inclination shows similar behaviours whether or not radiation reaction is switch on: protons (respectively electrons) impact less the surface of the neutron star as the inclination angle increases (decreases for electrons) while if the rotation and magnetic axes are aligned, all the protons impact onto the neutron star, and all the electrons impact the surface if the rotation and magnetic axes are anti-aligned. Similarly, we still find that particles can be ejected away from the neutron star, with preferred directions, were it for the number of particles or for their Lorentz factors

We conducted 3D-MHD simulations to investigate the feedback processes in the central 1kpc scale of galaxies hosting both active star formation (SF) and an AGN wind. Our simulations naturally generated a turbulent and clumpy interstellar medium driven by SF evolution. We found that the AGN wind duty cycle plays a crucial role in shaping the evolution of the outflows. This cycle consists of an active, a remnant and an inactive phase, lasting up to 1.5 Myr. The duration of the cycle increases with larger star formation rate (SFR) and smaller AGN wind power (tested for luminosities log L = 42-44 ergs per second and SFR=1-1000 solar masses per year. The feedback on SF, whether positive or negative, depends on various factors, including the AGN outflow opening angle, power, and phase of activity, as well as the initial SFR. The passage of the AGN wind enhances SF in a ring around it, resembling the structures observed in ULIRGs, and is stronger for larger AGN power or SFR. Also, a higher SFR enhances the mixing of interstellar matter with the AGN wind, resulting in a greater number of colder, denser structures with volume filling factors ~ 0.02 to 0.12 and velocities comparable to those observed in Seyferts and LINERs, but smaller than those observed in ULIRGs. The efficiency of the AGN wind in transporting mass to kiloparsec distances diminishes with increasing SFR. The mass loss rates range from 50 to 250 solar masses per year within the initial 2 Myr of evolution, which aligns with observed rates in nearby Seyferts and ULIRGs.

We present a new dust extinction technique with which we are able to retrieve parsec-scale gas surface density maps for entire nearby galaxies. The method measures the dust attenuation in optical bands on a pixel-by-pixel basis against a smoothed, reconstructed stellar distribution. The contribution of foreground light along the line-of-sight is calibrated using dust emission observations, assuming that the dust sits in a layer close to the mid-plane of the face-on galaxy. Here, we apply this technique to M51 (NGC 5194) as a proof-of-concept, obtaining a resolution of 0.14" (5 pc). Our dust (and gas) surface density map is consistent with independent dust- and CO-based studies at lower resolution. We find that discrepancies between our estimates of surface density and other studies stem primarily from the choice of dust model (i.e. different dust absorption coefficients). When assuming the same dust opacity law, our technique produces surface densities that are consistent with independent studies. This dust extinction technique provides us with gas surface density maps at an unprecedented resolution for full disc coverage studies of nearby galaxies. The resulting well-resolved spatial information opens the possibility for more in-depth examination of the influence of large-scale dynamics (and also stellar feedback mechanisms) on the interstellar medium at parsec-scales, and consequently star formation in nearby galaxies.

Diagnostic diagrams of emission-line ratios have been used extensively to categorize extragalactic emission regions; however, these diagnostics are occasionally at odds with each other due to differing definitions. In this work, we study the applicability of supervised machine-learning techniques to systematically classify emission-line regions from the ratios of certain emission lines. Using the Million Mexican Model database, which contains information from grids of photoionization models using \texttt{cloudy}, and from shock models, we develop training and test sets of emission line fluxes for three key diagnostic ratios. The sets are created for three classifications: classic \hii{} regions, planetary nebulae, and supernova remnants. We train a neural network to classify a region as one of the three classes defined above given three key line ratios that are present both in the SITELLE and MUSE instruments' band-passes: [{\sc O\,iii}]$\lambda5007$/H$\beta$, [{\sc N\,ii}]$\lambda6583$/H$\alpha$, ([{\sc S\,ii}]$\lambda6717$+[{\sc S\,ii}]$\lambda6731$)/H$\alpha$. We also tested the impact of the addition of the [{\sc O\,ii}]$\lambda3726,3729$/[{\sc O\,iii}]$\lambda5007$ line ratio when available for the classification. A maximum luminosity limit is introduced to improve the classification of the planetary nebulae. Furthermore, the network is applied to SITELLE observations of a prominent field of M33. We discuss where the network succeeds and why it fails in certain cases. Our results provide a framework for the use of machine learning as a tool for the classification of extragalactic emission regions. Further work is needed to build more comprehensive training sets and adapt the method to additional observational constraints.

We perform numerical simulations of supersonic magnetohydrodynamic (MHD) turbulence and calculate Fourier power spectra of E and B modes arising from dust polarization. We pay close attention to the ratio of E-mode to B-mode spectra (a.k.a. E/B power asymmetry) on small spatial scales. We find that the ratio depends on the strength of the mean magnetic field: the stronger the mean magnetic field is, the smaller the ratio is. More precisely speaking, the ratio scales with the Alfv\'en Mach number $M_A$, the root-mean-square velocity divided by the Alfv\'en speed of the mean magnetic field, when it lies in the range $1\lesssim M_A \lesssim 30$. This result implies that we can use the E/B power asymmetry to constrain the strength of the mean magnetic field in supersonic and super-Alfv\'enic MHD turbulence.

In this work, we analyzed the long term gamma-ray data by a Fermi Large Area Telescope (Fermi-LAT) of blazar S2 0109+22, ranging from 2008 to 2023. The quasi-periodic oscillations (QPOs) of blazars aided in investigating the physical properties of internal supermassive black holes, the nature of variability, and the underlying radiation mechanism. We employed four different methods--Weighted Wavelet Z-transform, Lomb-Scargle periodogram, REDFIT and phase folded light curve analysis, for searching QPO signals. Our analysis identified a possible QPO behavior with a periodicity of $\sim$600 days in November 2013 to January 2023 at a significance level of 3.5 $\sigma$. This QPO signal sustained $\sim$9 years, corresponding to 5.6 cycles, which was in good agreement with the previously observed of periodicity $\sim$657 days in radio. We explained this phenomenon based on the accretion model and the lighthouse effect, in a binary black hole system.

Space asteroseismology is revolutionizing our knowledge of the internal structure and dynamics of stars. A breakthrough is ongoing with the recent discoveries of signatures of strong magnetic fields in the core of red giant stars. The key signature for such a detection is the asymmetry these fields induce in the frequency splittings of observed dipolar mixed gravito-acoustic modes. We investigate the ability of the observed asymmetries of the frequency splittings of dipolar mixed modes to constrain the geometrical properties of deep magnetic fields. We use the powerful analytical Racah-Wigner algebra used in Quantum Mechanics to characterize the geometrical couplings of dipolar mixed oscillation modes with various possible realistic fossil magnetic fields' topologies and compute the induced perturbation of their frequencies. First, in the case of an oblique magnetic dipole, we provide the exact analytical expression of the asymmetry as a function of the angle between the rotation and magnetic axes. Its value provides a direct measure of this angle. Second, considering a combination of axisymmetric dipolar and quadrupolar fields, we show how the asymmetry is blind to unravel the relative strength and sign of each component. Finally, in the case of a given multipole, we show that a negative asymmetry is a signature of non-axisymmetric topologies. Therefore, asymmetries of dipolar mixed modes provide key but only partial information on the geometrical topology of deep fossil magnetic fields. Asteroseismic constraints should therefore be combined with spectropolarimetric observations and numerical simulations, which aim to predict the more probable stable large-scale geometries.

A chemodynamical model of our galaxy is fitted to data from DR17 of the APOGEE survey supplemented with data from the StarHorse catalogue and gaia DR3. Dynamically, the model is defined by action-based distribution functions for dark matter and six stellar components plus a gas disc. The gravitational potential jointly generated by the model's components is used to examine the galaxy's chemical composition within action space. The observational data probably cover all parts of action space that are populated by stars. The overwhelming majority of stars have angular momentum J_\phi>0 implying that they were born in the Galactic disc. High-alpha stars dominate in a region that is sharply bounded by J_\phi \la J_\phi(solar). Chemically the model is defined by giving each stellar component a Gaussian distribution in ([Fe/H],[Mg/Fe]) space about a mean that is a linear function of the actions. The model's 47 dynamical and 70 chemical parameters are chosen to maximise the likelihood of the data given the model in 72 three-dimensional velocity spaces and 30 two-dimensional chemical spaces. The circular speed falls steadily from 237\kms at R=4\kpc to 218\kms at R=20\kpc. Dark matter contributes half the radial force on the Sun and has local density 0.011\msun\pc^{-3}, there being 24.5\msun\pc^{-2} in dark matter and 26.5\msun\pc^{-2} in stars within 1.1\kpc of the plane.

The first bright objects to form in the Universe at redshift $z \sim 10-20$ might have been Dark Stars, made primarily of hydrogen and helium but powered by dark matter. In this study, we investigate the detectability of Supermassive Dark Stars (SMDS) by the Roman Space Telescope. RST will be able to detect SMDSs at redshifts as high as $z\simeq 14$. In cases with gravitational lensing factors of $\mu\sim 100$, RST will be able to find SMDS as small as $\sim10^4 M_{\odot}$ at $z\sim 12$ with $\sim 10^6$ s of exposure. To differentiate SMDS from early galaxies containing zero metallicity stars at similar redshifts, we compare their spectra, photometry in RST bands, color indexes and image morphology. With RST alone, the differentiation is possible only for limited cases: SMDS formed via "adiabatic contraction" (DM pulled into the star via gravity alone) with $M\gtrsim 10^5M_{\odot}$ and lensed by $\mu\gtrsim 30$ have distinct photometric signatures from those of the first galaxies. For SMDSs formed via "dark matter capture," their spectra are degenerate to those of many galaxies with little to no nebular emission. Thus with RST alone, the only way to tell them apart from first galaxies would be via image morphology: i.e. point object (SMDSs) vs. extended object (sufficiently magnified galaxies). However, if the same objects are further examined by JWST spectroscopy, a "smoking gun" for detection of SMDS is the HeII $\lambda$1640 absorption line. While RST does not cover the wavelength band required to find this line (for $z_{\rm emi}\gtrsim 10$), JWST does. Hence the two detectors can be used together in identifying SMDS. The confirmed detection of any SMDSs will provide evidence for a new type of star, powered by dark matter. Moreover, such massive stars can also be natural progenitors of the supermassive black holes powering the extremely bright quasars observed at $z\gtrsim 6$.

We present a multi-band photometric analysis of CRTS J163819.6+03485, the first low mass ratio (LMR) contact binary system with a period under the contact binary (CB) period limit. The unprecedented combination of mass ratio and period makes this system unique for eclipsing binary (EB) research. Using new multi-band photometric observations, we explored the parameter space of this unique total EB system through a detailed scan in the mass ratio - inclination plane and using the PIKAIA genetic algorithm optimizer. The best set of relative physical parameters and corresponding uncertainties was adopted through Markov Chain Monte Carlo sampling of the parameter space. The resulting mass ratio of the system is $q = 0.16 \pm 0.01$. The absolute parameters were derived by adopting an empirical mass-luminosity relation. Period changes are also investigated by using new observations and archival photometric light curves from massive astronomical surveys, which revealed in a preliminary solution the presence of a possible low-mass tertiary companion. The origin and evolutionary status of the system are investigated through the detached-binary formation scenario.

Planetesimal formation is still mysterious. One of the ways to form planetesimals is to invoke a gas pressure bump in a protoplanetary disc. In our previous paper, we propose a new scenario in which the piled-up dust at a gas pressure bump created by a migrating planet form planetesimals by streaming instability in a wide region of the disc as the planet migrates inward. In this work, we consider the global time evolution of dust and investigate the detailed conditions and results of the planetesimal formation in our scenario. We use a 1D grid single-sized dust evolution model, which can follow the growth of the particles by their mutual collision and their radial drift and diffusion. We calculate the time-evolution of the radial distribution of the peak mass and surface density of the dust in a gas disc perturbed by an embedded migrating planet and investigate if the dust satisfies the condition for planetesimal formation. We find that planetesimals form in a belt-like region between the snowline and the position where the planet reaches its pebble-isolation mass when the strength of turbulence is $10^{-4}\leq\alpha\leq10^{-3}$, which is broadly consistent with observed value. The mechanism of the formation, streaming instability or mutual collision, depends on the timescale of the streaming instability. The total mass of planetesimals also depends on $\alpha$ and is about $30-100~M_{\rm E}$ if the planetary core has already existed at the beginning and grows by gas accretion, but it decreases as the timing of the formation of the planetary core is later. We also provide simple approximate expressions of the surface density and total mass of the planetesimals and find that the total mass strongly depends on the dust mass. We show that planetesimals form in a belt-like region by the combination of the dust pile-up at the gas pressure bump formed by a planet and its inward migration.

This study investigates the application of Large Language Models (LLMs), specifically GPT-4, within Astronomy. We employ in-context prompting, supplying the model with up to 1000 papers from the NASA Astrophysics Data System, to explore the extent to which performance can be improved by immersing the model in domain-specific literature. Our findings point towards a substantial boost in hypothesis generation when using in-context prompting, a benefit that is further accentuated by adversarial prompting. We illustrate how adversarial prompting empowers GPT-4 to extract essential details from a vast knowledge base to produce meaningful hypotheses, signaling an innovative step towards employing LLMs for scientific research in Astronomy.

The ages of solar-like stars have been at the center of many studies such as exoplanet characterization or Galactic-archaeology. While ages are usually computed from stellar evolution models, relations linking ages to other stellar properties, such as rotation and magnetic activity, have been investigated. With the large catalog of 55,232 rotation periods, $P_{\rm rot}$, and photometric magnetic activity index, $S_{\rm ph}$ from Kepler data, we have the opportunity to look for such magneto-gyro-chronology relations. Stellar ages are obtained with two stellar evolution codes that include treatment of angular momentum evolution, hence using $P_{\rm rot}$ as input in addition to classical atmospheric parameters. We explore two different ways of predicting stellar ages on three subsamples with spectroscopic observations: solar analogs, late-F and G dwarfs, and K dwarfs. We first perform a Bayesian analysis to derive relations between $S_{\rm ph}$ and ages between 1 and 5 Gyr, and other stellar properties. For late-F and G dwarfs, and K dwarfs, the multivariate regression favors the model with $P_{\rm rot}$ and $S_{\rm ph}$ with median differences of 0.1%.and 0.2% respectively. We also apply Machine Learning techniques with a Random Forest algorithm to predict ages up to 14 Gyr with the same set of input parameters. For late-F, G and K dwarfs together, predicted ages are on average within 5.3% of the model ages and improve to 3.1% when including $P_{\rm rot}$. These are very promising results for a quick age estimation for solar-like stars with photometric observations, especially with current and future space missions.

WD0810-353 is a white dwarf within the 20pc volume around the Sun. Using Gaia astrometric distance and proper motions, and a radial velocity derived from Gaia spectroscopy, it has been predicted that this star will pass within 1pc of the Solar System in about 30kyr. However, WD0810-353 has been also shown to host a magnetic field with strength of the order of 30MG. Its spectrum is therefore not like those of normal DA stars of similar effective temperature. We have obtained and analysed new polarised spectra of the star around Halpha. Our analysis suggests that the visible surface of the star shows two regions of different field strength (~30 and ~45MG, respectively), and opposite polarity. The spectra do not change over a 4 year time span, meaning that either the stellar rotation period is no shorter than several decades, or that the field is symmetric about the rotation axis. Taking into account magnetic shift and splitting, we obtain an estimate of the radial velocity of the star (+83+/- 140km/s); we reject both the value an the claimed precision deduced from the Gaia DR3 spectroscopy (-373.7+/- 8.2km/s), and we conclude that there will probably be no close encounter between the Solar System and WD0810-353. We also reject the suggestion that the star is a hypervelocity runaway star, a survivor of a Type Ia Supernova explosion. It is just a stellar remnant in the Solar neighborhood with a very strong and complex magnetic field.

The bulk kinematics and thermodynamics of hot supernovae-driven galactic winds is critically dependent on both the amount of swept up cool clouds and non-spherical collimated flow geometry. However, accurately parameterizing these physics is difficult because their functional forms are often unknown, and because the coupled non-linear flow equations contain singularities. We show that deep neural networks embedded as individual terms in the governing coupled ordinary differential equations (ODEs) can robustly discover both of these physics, without any prior knowledge of the true function structure, as a supervised learning task. We optimize a loss function based on the Mach number, rather than the explicitly solved-for 3 conserved variables, and apply a penalty term towards near-diverging solutions. The same neural network architecture is used for learning both the hidden mass-loading and surface area expansion rates. This work further highlights the feasibility of neural ODEs as a promising discovery tool with mechanistic interpretability for non-linear inverse problems.

The Tayler-Spruit dynamo mechanism has been proposed two decades ago as a plausible mechanism to transport angular momentum in radiative stellar layers. Direct numerical simulations are still needed to understand its trigger conditions and the saturation mechanisms. The present study follows up on (Petitdemange et al. 2023), where we reported the first numerical simulations of a Tayler-Spruit dynamo cycle. Here we extend the explored parameter space to assess in particular the influence of stratification on the dynamo solutions. We also present numerical verification of theoretical assumptions made in (Spruit 2002), which are instrumental in deriving the classical prescription for angular momentum transport implemented in stellar evolution codes. A simplified radiative layer is modeled numerically by considering the dynamics of a stably-stratified, differentially rotating, magnetized fluid in a spherical shell. Our simulations display a diversity of magnetic field topologies and amplitudes depending on the flow parameters, including hemispherical solutions. The Tayler-Spruit dynamos reported here are found to satisfy magnetostrophic equilibrium and achieve efficient turbulent transport of angular momentum, following Spruit's heuristic prediction.

Light curves are the primary observable of type-I x-ray bursts. Computational x-ray burst models must match simulations to observed light curves. Most of the error in simulated curves comes from uncertainties in $rp$ process reaction rates, which can be reduced via precision mass measurements of neutron-deficient isotopes in the $rp$ process path. We perform a precise atomic mass measurement of $^{27}$P and use this new measurement to update existing type-I x-ray burst models to produce an improved light curve. High-precision Penning trap mass spectrometry was used to determine the atomic mass of $^{27}$P. Modules for Experiments in Stellar Astrophysics (MESA) was then used to simulate x-ray bursts using a 1D multi-zone model to produce updated light curves. The mass excess of $^{27}$P was measured to be -670.7$\pm$ 0.6 keV, a fourteen-fold precision increase over the mass reported in AME2020. The $^{26}$Si($p, \gamma$)$^{27}$P and reverse photodisintegration reaction rates have been determined to a higher precision based on the new, high precision mass measurement of $^{27}$P, and MESA light curves generated using these rates. Changes in the mass of $^{27}$P seem to have minimal effect on XRB light curves, even in burster systems tailored to maximize impact. The mass of $^{27}$P does not play a significant role in x-ray burst light curves. It is important to understand that more advanced models don't just provide more precise results, but often qualitatively different ones. This result brings us a step closer to being able to extract stellar parameters from individual x-ray burst observations. In addition, the Isobaric Multiplet Mass Equation (IMME) has been validated for the $A=27, T=3/2$ quartet, but only after including a small, theoretically predicted cubic term and utilizing an updated excitation energy for the $T=3/2$ isobaric analogue state of $^{27}$Si.

Recent findings from the Neutron Star Interior Composition Explorer (NICER) have opened up opportunities to investigate the potential coupling between matter and geometry, along with its resulting physical implications. Millisecond pulsars serve as an ideal subject for conducting such tests and examining these phenomena. We apply the field equations of modified gravity, $f(R, T)=R+\alpha\, T$ to a spherically symmetric spacetime, where $R$ is the Ricci scalar, $\alpha$ is a dimensional parameter, and $T$ is the matter of the geometry. Five unknown functions are present in the output system of differential equations, which consists of three equations. To close the system, we make explicit assumptions about the anisotropy and the radial metric potential, $g_{rr}$. We then solve the output differential equations and derive the explicit forms of the components of the energy-momentum tensor, namely, density, radial, and tangential pressures.

In the first decade of the 20th century, the Universidad Nacional de La Plata, founded in 1905, created a modern and well-equipped Physics Institute. In this paper we study the impact that this initiative had on the modernisation of physics teaching at secondary and university level in Argentina. We focus on two of the most representative graduates of the Institute in those years, Ramon G. Loyarte and Enrique Loedel Palumbo, and analyse their most important pedagogical works and the public reception they received. These works are a sample of the contribution of the Institute of Physics to the raising of the level of national education in the field of physical sciences in the first half of the 20th century.

A new intrinsically-relativistic kinetic mechanism for generation of non-isotropic relativistic kinetic equilibria in collisionless N-body systems is pointed out. The theory is developed in the framework of the covariant Vlasov statistical description. The new effect is based on the constraints placed by the conservation laws of neutral single-particle dynamics in prescribed background curved-spacetimes demonstrating existence of Killing tensors. As an illustration, the particular case of the Kerr space-time admitting the so-called Carter constant for the particle geodesic motion is considered. The general functional form of the equilibrium kinetic distribution function (KDF) is determined and an explicit realization in terms of Gaussian-like distributions is provided. It is shown that, due to the Carter constant, these equilibrium KDFs exhibit an anisotropic phase-space functional dependence in terms of the single-particle 4-velocity components, giving rise to corresponding non-isotropic continuum fluid fields. The qualitative properties of the equilibrium stress-energy tensor associated with these systems are discussed, with a particular emphasis on the related occurrence of temperature anisotropy effects. The theory is susceptible of astrophysical applications, including in particular the statistical properties of dark matter halos around stellar-mass or galactic-center black holes.

Binary compact objects will be among the important sources for the future space-based gravitational wave detectors. Such binary compact objects include stellar massive binary black hole, binary neutron star, binary white dwarf and mixture of these compact objects. Regarding to the relatively low frequency, the gravitational interaction between the two objects of the binary is weak. Post-Newtonian approximation of general relativity is valid. Previous works about the waveform model for such binaries in the literature consider the dynamics for specific situations which involve detailed complicated matter dynamics between the two objects. We here take a different idea. We adopt the trick used in pulsar timing detection. For any gravity theories and any detailed complicated matter dynamics, the motion of the binary can always be described as a post-Keplerian expansion. And a post-Keplerian gravitational waveform model will be reduced. Instead of object masses, spins, matter's equation of state parameters and dynamical parameters beyond general relativity, the involved parameters in our post-Keplerian waveform model are the Keplerian orbit elements and their adiabatic variations. Respect to current planning space-based gravitational wave detectors including LISA, Taiji and Tianqin, we find that the involved waveform model parameters can be well determined. And consequently the detail matter dynamics of the binary can be studied then. For binary with purely gravitational interactions, gravity theory can be constrained well.

General Relativistic Entropic Acceleration (GREA) gives a general framework in which to study multiple out-of-equilibrium phenomena in the context of general relativity, like the late accelerated expansion of the universe or the formation of galaxies and the large scale structure of the universe. Here we study the consequences of mass accretion onto massive Black Holes. We find that a population of Super Massive Black Holes (SMBH) whose mass grows significantly due to accretion can act as a source of entropic acceleration and constitute a significant part of the present acceleration of the Universe.

We investigate the spherically-symmetric gravitational collapse of a massless scalar field in the framework of a type-II minimally modified gravity theory called VCDM. This theory propagates only two local physical degrees of freedom supplemented by the so-called instantaneous (or shadowy) mode. Imposing asymptotically flat spacetime in the standard Minkowski time slicing, one can integrate out the instantaneous mode. Consequently, the equations of motion reduce to those in general relativity (GR) with the maximal slicing. Unlike GR, however, VCDM lacks 4D diffeomorphism invariance, and thus one cannot change the time slicing that is preferred by the theory. We then numerically evolve the system to see if and how a black hole forms. For small amplitudes of the initial scalar profile, we find that its collapse does not generate any black hole, singularity or breakdown of the time slicing. For sufficiently large amplitudes, however, the collapse does indeed result in the formation of an apparent horizon in a finite time. After that, the solution outside the horizon is described by a static configuration, i.e. the Schwarzschild geometry with a finite and time-independent lapse function. Inside the horizon, on the other hand, the numerical results indicate that the lapse function keeps decreasing towards zero so that the central singularity is never reached. This implies the necessity for a UV completion of the theory to describe physics inside the horizon. Still, we can conclude that VCDM is able to fully describe the entire time evolution of the Universe outside the black hole horizon without knowledge about such a UV completion.

The two-Higgs-doublet with additional scalar (2HDM$+S$) model is one proposed to account for several anomalies that have persisted and increased in significance over runs 1 and 2 at the Large Hadron Collider (LHC). In addition to this, 2HDM+$S$ also supplies a potential Dark Matter (DM) candidate coupling to the Standard Model via the $S$ boson. So far, this model has been difficult to constrain by indirect means. Here we will explore the potential of Omega Centauri, a nearby globular cluster to constrain this interesting DM model. Although such structures are generally considered to be lacking in DM, arguments have been made that this cluster is in fact the relic of a tidally stripped dwarf galaxy. In such a scenario, the DM content would be significant. Combined with its nearness, this would suggest a potential for powerful indirect dark matter signals. We employ both Fermi-LAT gamma-ray data, as well as MeerKAT telescope sensitivities to determine the current status of Omega Centauri as a source of indirect constraints on Weakly Interacting Massive Particles (WIMPs) in a 2HDM+$S$ scenario and for general annihilation channels.

The presence of dark matter overdensities surrounding a black hole can influence the evolution of a binary system. The gravitational wave signals emitted by a black hole binary offer a promising means to probe the dark matter environments near a black hole. The dense region of dark matter can lead to the dephasing of gravitational waveforms, which can be detected by upcoming experiments such as the Laser Interferometer Space Antenna (LISA). The dark matter density profile around the black hole can vary for different dark matter models. Our study specifically investigates the impact of the ultralight self-interacting scalar dark matter (SIDM) on the gravitational wave signals emitted by black hole binaries. A distinctive characteristic of SIDM surrounding a black hole, as opposed to collisionless dark matter, is the formation of a soliton core. We perform a Fisher matrix analysis to estimate the size of the soliton and the corresponding SIDM parameter space that future LISA-like gravitational wave experiments can explore.

In modern cosmology, scalar fields with screening mechanisms are often used as explanations for phenomena like dark energy or dark matter. Amongst a zoo of models, the environment dependent dilaton, screened by the Polyakov-Damour mechanism, is one of the least constrained ones. Using recently developed path integral tools for directly computing reduced density matrices, we study the open quantum dynamics of a probe, modelled by another real scalar field, induced by interactions with an environment comprising fluctuations of a dilaton. As the leading effect, we extract a correction to the probe's unitary evolution, which can be observed as a frequency shift. Assuming the scalar probe to roughly approximate a cold atom in matter wave interferometry, we show that comparing the predicted frequency shifts in two experimentally distinct setups has the potential to exclude large parts of the dilaton parameter space.

Recent progress in quantum computing and the development of novel detector technologies for astrophysics is driving the need for high-gain, broadband, and quantum-limited amplifiers. We present a purely traveling-wave parametric amplifier (TWPA) using an inverted NbTiN microstrip and amorphous Silicon dielectric. Through dispersion engineering, we are able to obtain $50~\Omega$ impedance matching and suppress undesired parametric processes while phase matching the three-wave-mixing amplification across a large range of frequencies. The result is a broadband amplifier operating with 20 dB gain and quantum-limited noise performance at 20 mK. At the single frequency where the amplifier is phase sensitive, we further demonstrate 8 dB of vacuum noise squeezing.

We address two important questions in gravitational-wave astronomy. What is the astrophysical formation scenario leading to black-hole binary mergers? Did some of the merging black holes form hierarchically through previous generations of mergers? Leveraging fast-to-generate astrophysical simulations from the rapster code and a random forest algorithm, we develop a pipeline to accurately classify the most likely generation and formation scenario of dynamically formed BHs on an event-by-event basis. We test our framework on four merger events with features suggesting a dynamical origin: the large total mass event GW190521, GW190412 (with large mass asymmetry), and two events with effective spins antialigned with the orbital angular momentum (GW191109 and GW200225). Within the models we consider, and assuming these events to be formed dynamically, we find that one of the component black holes in GW190521 formed from a previous merger with high probability ($\gtrsim 85\%$). GW190521, GW191109 and GW200225 are compatible with formation through three-body interactions, while the most likely formation channel for GW190412 are two-body captures. We also rule out that GW191109 contains only first-generation black holes with a probability of 97$\%$. Our pipeline could be useful to identify the evolutionary path of individual GW observations once it is trained on more comprehensive sets of binary formation simulations.

New probes of neutrino mixing are needed to advance precision studies. One promising direction is via the detection of low-energy atmospheric neutrinos (below a few hundred MeV), to which a variety of near-term experiments will have much-improved sensitivity. Here we focus on probing these neutrinos through distinctive nuclear signatures of exclusive neutrino-carbon interactions -- those that lead to detectable nuclear-decay signals with low backgrounds -- in both neutral-current and charged-current channels. Here the neutral-current signature is a line at 15.11 MeV and the charged-current signatures are two- or three-fold coincidences with delayed decays. We calculate the prospects for identifying such events in the Jiangmen Underground Neutrino Observatory (JUNO), a large-scale liquid-scintillator detector. A five-year exposure would yield about 16 neutral-current events (all flavors) and about 16 charged-current events (mostly from $\nu_e + \bar{\nu}_e$, with some from $\nu_\mu + \bar{\nu}_\mu$), and thus roughly 25\% uncertainties on each of their rates. Our results show the potential of JUNO to make the first measurement of sub-100 MeV atmospheric neutrinos. They also a step towards multi-detector studies of low-energy atmospheric neutrinos, including with the goal of identifying additional distinctive nuclear signatures for carbon and other targets.

We consider the classical attractor regime of the spectator Abelian Higgs model in power-law inflation, and compute the one-loop corrections to its evolution. For computations we utilize dimensional regularization and the propagators in the unitary gauge. The corrections to both the scalar condensate and the energy-momentum tensor exhibit secular ultraviolet contributions, that tend to slow down the rolling of the scalar down its potential, and drive it away from the classical attractor. These corrections need not be suppressed if the U(1) charge is much larger than the scalar self-coupling, which is seen already in flat space. In addition, at late times the secular corrections necessarily invalidate the perturbative loop expansion. We find the late time secular corrections to be captured by the renormalization group, which opens up the possibility to resum them past the breakdown of perturbativity.

Binary systems containing exotic compact objects may emit repeated bursts of gravitational waves (GWs) following coalescence. Such GW echoes would provide a clear signature of new physics, but searches for them have not yielded a convincing detection. Here we argue that the typical time delay between a GW event and its echoes is much greater than generally expected, due to long propagation times through objects that mimic black holes. We provide a simple recipe for computing the time delay and several examples. These time delays can be billions of years, resulting in rogue echoes that are not correlated with GW events and evade all current constraints. They would be detectable only by searches for individual echoes or GW bursts.

The horizon of a flat Friedmann--Robertson--Walker (FRW) universe is considered to be dynamic when the Hubble parameter $H$ and the Hubble radius $r_{H}$ vary with time, unlike for de Sitter universes. To clarify the thermodynamics on a dynamic horizon, the evolution of a dynamical Kodama--Hayward temperature and Bekenstein--Hawking entropy on the horizon of a flat FRW universe is examined in a $\Lambda(t)$ model similar to time-varying $\Lambda(t)$ cosmologies. The $\Lambda(t)$ model includes both a power-law term proportional to $H^{\alpha}$ (where $\alpha$ is a free variable) and the equation of state parameter $w$, extending a previous analysis [Phys. Rev. D 100, 123545 (2019) (arXiv:1911.08306)]. Using the present model, a matter-dominated universe ($w=0$) and a radiation-dominated universe ($w=1/3$) are examined, setting $\alpha <2$. Both universes tend to approach de Sitter universes and satisfy the maximization of entropy in the last stage. The evolution of several parameters (such as the Bekenstein--Hawking entropy) is similar for both $w=0$ and $w=1/3$, though the dynamical temperature $T_{H}$ is different. In particular, $T_{H}$ is found to be constant when $w=1/3$ with $\alpha=1$, although $H$ and $r_{H}$ vary with time. To discuss this case, the specific conditions required for constant $T_{H}$ are examined. Applying the specific condition to the present model gives a cosmological model that can describe a universe at constant $T_{H}$, as if the dynamic horizon is in contact with a heat bath. The relaxation processes for the universe are also discussed.

The values of the bending delays in the signal of a radio pulsar in a binary with a stellar mass black hole as a companion have been calculated accurately within a full general relativistic framework considering the Schwarzchid spacetime near the companion. The results match with the pre-existing approximate analytical expressions unless both of the orbital inclination angle and the orbital phase are close to $90^{\circ}$. For such a case, the approximate analytical expressions underestimate the value of the bending delay. On the other hand, for systems like the double pulsar, those expressions are valid throughout the orbital phase, unless its inclination angle is very close to 90 degrees. For a pulsar-black hole binary, the bending phenomenon also increases the strength of the pulse profile and sometimes can lead to a small low intensity tail.

The trajectory of Earth about the Sun is perturbed by torques exerted by the Moon and Sun, and also the four giant planets. These provoke variations of insolation at Earth surface, known as kyr-long Milankovi\'c cycles. The concept has been extended to the shorter time scales of years to centuries, that are relevant to tree growth. This paper focuses on iSSA of results of the dendro-chronological study of a forest of long-lived Tibetan junipers. From this, we determine a median curve of tree growth rates, that is analyzed by iSSA. We obtain a rich set of (pseudo-) periods, from 3.3 yr up to more than 1000 years, that compare with the specific spectral signature found in the sunspot and length-of-day time series. We discuss in detail the record from a single tree that spans almost completely the 357-2000 AD interval. The 90 yr Gleissberg, 22 yr and 30 yr components are quite prominent. The Oort, Wolf, Sp\"orer, Maunder and Dalton climate extrema all correspond quite precisely to extrema of the Gleissberg cycle. The well-known Medieval Climate Optimum, Little Ice Age and Modern Climate Optimum all seem to be mainly forced by variations in the envelope of the Gleissberg cycle. The Gleissberg cycle is strongly modulated with a period of 500-600 years. The node near a small gap in the data is very close to the Medieval Climate Optimum. Observations in different parts of Earth are in favor of a global extension of the MCO. In the same way that the Milankovic mathematical theory of climate allows one to relate climate change and length of day, through changes in inclination of Earth's rotation axis and solar insolation, it is reasonable to propose that the set of pseudo-periods that are evidenced in the Tibetan tree ring growth rates simply corresponds to short period Milankovi\'c cycles. The Dulan forest could be considered as a good candidate for a continuous, global geophysical observatory.

Earth can act as a transducer to convert ultralight bosonic dark matter (axions and hidden photons) into an oscillating magnetic field with a characteristic pattern across its surface. Here we describe the first results of a dedicated experiment, the Search for Non-Interacting Particles Experimental Hunt (SNIPE Hunt), that aims to detect such dark-matter-induced magnetic-field patterns by performing correlated measurements with a network of magnetometers in relatively quiet magnetic environments (in the wilderness far from human-generated magnetic noise). Our experiment constrains parameter space describing hidden-photon and axion dark matter with Compton frequencies in the 0.5-5.0 Hz range. Limits on the kinetic-mixing parameter for hidden-photon dark matter represent the best experimental bounds to date in this frequency range.

We show that -- in the framework of general relativity (GR) -- if black holes (BHs) are singularity-free objects, they couple to the large-scale cosmological dynamics. We find that the leading contribution to the resulting growth of the BH mass ($M_{\rm BH}$) as a function of the scale factor $a$ stems from the curvature term, yielding $M_{\rm BH} \propto a^k$, with $k=1$. We demonstrate that such a linear scaling is universal for spherically-symmetric objects, and it is the only contribution in the case of regular BHs. For nonsingular horizonless compact objects we instead obtain an additional subleading model-dependent term. We conclude that GR nonsingular BHs/horizonless compact objects, although cosmologically coupled, are unlikely to be the source of dark energy. We test our prediction with astrophysical data by analysing the redshift dependence of the mass growth of supermassive BHs in a sample of elliptical galaxies at redshift $z=0.8 -0.9$. We also compare our theoretical prediction with higher redshift BH mass measurements obtained with the James Webb Space Telescope (JWST). We find that, while $k=1$ is compatible within $2\sigma$ with JWST results, the data from elliptical galaxies at $z=0.8 -0.9$ favour values of $k>1$. New samples of BHs covering larger mass and redshift ranges and more precise BH mass measurements are required to settle the issue.

Here, we study the generalized second law (GSL) of thermodynamics in the framework of massive gravity. To do this, we consider a FRW universe filled only with matter and enclosed by the apparent horizon. In addition, we consider two models including generalized massive gravity (GMG) as well as dRGT massive gravity on de Sitter. For both models, we first study the dynamics of background cosmology and then explore the validity of GSL. We conclude that for the selected values of model parameters the GSL is respected.

We show that gravity models, such as $f(\mathcal{L}_{\rm m})$, $f(g_{\mu\nu} T^{\mu\nu})$ and $f(T_{\mu\nu} T^{\mu\nu})$, that modify the introduction of the material source in the usual Einstein-Hilbert action by adding only matter-related terms to the matter Lagrangian density $\mathcal{L}_{\rm m}$ are equivalent to general relativity with nonminimal interactions. Through the redefinition $\mathcal{L}_{\rm m}+f \rightarrow \mathcal{L}_{\rm m}^{\rm tot}$, these models are exactly GR, yet the usual material field $T_{\mu\nu}$ and its accompanying partner, viz., the modification field $T_{\mu\nu}^{\rm mod}$ interact nonminimally. That is, $\nabla^{\mu}T_{\mu\nu}=-Q_{\nu}=-\nabla^{\mu}T_{\mu\nu}^{\rm mod}$, where $Q_{\nu}$ is the interaction kernel that governs the rate of energy transfer. We focus on the particular model, the energy-momentum squared gravity, where the usual material field $T_{\mu\nu}$ brings in an accompanying energy-momentum squared field , $T_{\mu\nu}^{\rm emsf}$ along with a sui generis nonminimal interaction between them. Compared to usual phenomenological nonminimal interaction models in the literature, EMSF gives rise to more intricate interaction kernels having covariant formulation even with simple forms of the $f$ function. We elaborate upon EMSF via some different aspects: a DE component induced from the interaction of sources such as cold dark matter and relativistic species with their accompanying EMSFs generating interacting DE-DM models, mimicking noncanonical scalar field, etc., or a Hoyle-type creation field generating steady-state universe models extended to fluids other than dust and a mimicker of modified generalized Chaplygin gas. We also demonstrate the proper calculation of second metric variation of $\mathcal{L}_{\rm m}$, as well as in models that contain scalars like $g_{\mu\nu} T^{\mu\nu}\,,R_{\mu\nu}T^{\mu\nu}$ and $G_{\mu\nu} T^{\mu\nu}$.