Papers for Wednesday, Aug 28 2024

In 2017, the next generation Very Large Array (ngVLA) Science Advisory Council, together with the international astronomy community, developed a set of five Key Science Goals (KSGs) to inform, prioritize and refine the technical capabilities of a future radio telescope array for high angular resolution operation from 1.2 - 116 GHz with 10 times the sensitivity of the Jansky VLA and ALMA. The resulting KSGs, which require observations at centimeter and millimeter wavelengths that cannot be achieved by any other facility, represent a small subset of the broad range of astrophysical problems that the ngVLA will be able address. This document presents an update to the original ngVLA KSGs, taking account of new results and progress in the 7+ years since their initial presentation, again drawing on the expertise of the ngVLA Science Advisory Council and the broader community in the ngVLA Science Working Groups. As the design of the ngVLA has also matured substantially in this period, this document also briefly addresses initial expectations for ngVLA data products and processing that will be needed to achieve the KSGs. The original ngVLA KSGs endure as outstanding problems of high priority. In brief, they are: (1) Unveiling the Formation of Solar System Analogues; (2) Probing the Initial Conditions for Planetary Systems and Life with Astrochemistry; (3) Charting the Assembly, Structure, and Evolution of Galaxies from the First Billion Years to the Present; (4) Science at the Extremes: Pulsars as Laboratories for Fundamental Physics; (5) Understanding the Formation and Evolution of Stellar and Supermassive Black Holes in the Era of Multi-Messenger Astronomy.

Supermassive stars (SMSs) and heavy seed black holes, as their remnants, are promising candidates for Supermassive Black Hole (SMBH) progenitors, especially for ones observed in the early universe $ z\simeq 8.5-10$ by recent JWST observations. Expected cradles of SMSs are the atomic cooling halos ($M_{\rm halo}\simeq 10^7~{\rm M_\odot}$), where "cold accretion" emerges and possibly forms SMSs. We perform a suit of cosmological radiation hydrodynamics simulations and investigate star formation after the emergence of cold accretion, solving radiative feedback from stars inside the halo. We follow the mass growth of the protostars for $\sim 3~{\rm Myr}$, resolving the gas inflow down to $\sim 0.1~{\rm pc}$ scales. We discover that, after cold accretion emerges, multiple SMSs of $m_\star \gtrsim 10^5{\rm M_\odot}$ form at the halo centre with the accretion rates maintained at $\dot{m}_\star \simeq 0.04~{\rm M_\odot}~{\rm yr^{-1}}$ for $\lesssim 3~{\rm Myr}$. Cold accretion supplies gas at a rate of $\dot{M}_{\rm gas}\gtrsim 0.01-0.1~{\rm M_\odot}~{\rm yr^{-1}}$ from outside the halo virial radius to the central gas disc. Gravitational torques from spiral arms transport gas further inward, which feeds the SMSs. Radiative feedback from stars suppresses H$_2$ cooling and disc fragmentation, while photoevaporation is prevented by a dense envelope, which attenuates ionising radiation. Our results suggest that cold accretion can bring efficient BH mass growth after seed formation in the later universe. Moreover, cold accretion and gas migration inside the central disc increase the mass concentration and provide a promising formation site for the extremely compact stellar clusters observed by JWST.

Cold New Early Dark Energy (Cold NEDE) addresses the Hubble tension through a triggered vacuum phase transition in the dark sector. In this paper, we constrain a phenomenological fluid model using recent cosmic microwave background likelihoods based on Planck NPIPE data alongside baryonic acoustic oscillations and supernovae data from Pantheon+. Exploiting the enhanced constraining power of the datasets, we introduce and study an extended version of the NEDE fluid model in which the equation of state parameter $w_\mathrm{NEDE}$, characterizing the post-phase transition fluid, is allowed to evolve with non-vanishing derivatives ${d}w_\mathrm{NEDE}/d\ln a$ and ${d^2}w_\mathrm{NEDE}/{d}(\ln a)^2$. Our results indicate that data is compatible with a rather simple time dependence that could arise from a mixture of radiation and a stiff fluid. With the updated datasets, the base and extended models still show a significant reduction of the DMAP tension from $6.3 \sigma$ in $\Lambda$CDM down to $3.5\sigma$ with a small simultaneous reduction of the $S_8$ tension, slightly improving over recent findings for the axion-like early dark energy model.

Intermediate Mass Black Hole (IMBH) mergers with masses $10^4 - 10^6$ $M_{\odot}$ are expected to produce gravitational waves (GWs) detectable by the Laser Interferometer Space Antenna (LISA) with high signal to noise ratios out to redshift 20. IMBH mergers are expected to take place within dwarf galaxies, however, the dynamics, timescales, and effect on their hosts are largely unexplored. In a previous study, we examined how IMBHs would pair and merge within nucleated dwarf galaxies. IMBHs in nucleated hosts evolve very efficiently, forming a binary system and coalescing within a few hundred million years. Although the fraction of dwarf galaxies ($10^7$ M$_{\odot} \leq$ $M_{\star} \leq 10^{10}$ M$_{\odot}$) hosting nuclear star clusters is between 60-100\%, this fraction drops to 20-70\% for lower-mass dwarfs ($M_{\star}\approx 10^7$ M$_{\odot}$), with the largest drop in low-density environments. Here, we extend our previous study by performing direct $N-$body simulations to explore the dynamics and evolution of IMBHs within non-nucleated dwarf galaxies, under the assumption that IMBHs exist within these dwarfs. To our surprise, none of IMBHs in our simulation suite merge within a Hubble time, despite many attaining high eccentricities $e \sim 0.7-0.95$. We conclude that extremely low stellar density environments in the centers of non-nucleated dwarfs do not provide an ample supply of stars to interact with IMBHs binary resulting in its stalling, in spite of triaxiality and high eccentricity, common means to drive a binary to coalescence. Our findings underline the importance of considering all detailed host properties to predict IMBH merger rates for LISA.

We study the 3.4-4.4$\mu$m fundamental rovibrational band of H3+, a key tracer of the ionization of the molecular interstellar medium (ISM), in a sample of 12 local (d< 400 Mpc) ultra/luminous infrared galaxies (U/LIRGs) observed with JWST/NIRSpec. The P, Q, and R branches of the band are detected in 13 out of 20 analyzed regions within these U/LIRGs, which increases the number of extragalactic H3+ detections by a factor of 6. For the first time in the ISM, the H3+ band is observed in emission in 3 of these regions. In the remaining 10 regions, the band is seen in absorption. The absorptions are produced toward the 3.4-4.4$\mu$m hot dust continuum rather than toward the stellar continuum, indicating that they likely originate in clouds associated with the dust continuum source. The H3+ band is undetected in Seyfert-like U/LIRGs where the mildly obscured X-ray radiation from the AGN might limit the abundance of this molecule. For the detections, the H3+ abundances, N(H3+)/N_H = (0.5-5.5)x10^-7, imply relatively high ionization rates between 3x10^-16 and >4x10^-15 s^-1, which are likely associated with high-energy cosmic rays. In half of the targets the absorptions are blue-shifted by 50-180 km/s, which are lower than the molecular outflow velocities measured using other tracers such as OH 119$\mu$m or rotational CO lines. This suggests that H3+ traces gas close to the outflow launching sites before it has been fully accelerated. We used nonlocal thermodynamic equilibrium models to investigate the physical conditions of these clouds. In 7 out of 10 objects, the H3+ excitation is consistent with inelastic collisions with H2 in warm translucent molecular clouds (T_kin ~ 250-500 K and n(H2) ~ 10^(2-3) cm^-3). In three objects, dominant infrared pumping excitation is required to explain the absorptions from the (3,0) and (2,1) levels of H3+ detected for the first time in the ISM.

One of the greatest challenges in galaxy evolution over the last decade has been constraining the prevalence of heavily dust-obscured galaxies in the early Universe. At $z>3$, these galaxies are increasingly rare, and difficult to identify as they are interspersed among the more numerous dust-obscured galaxy population at $z=1-3$, making efforts to secure confident spectroscopic redshifts expensive, and sometimes unsuccessful. In this work, we present the Extended Mapping Obscuration to Reionization with ALMA (Ex-MORA) Survey -- a 2mm blank-field survey in the COSMOS-Web field, and the largest ever ALMA blank-field survey to-date covering 577 arcmin$^2$. Ex-MORA is an expansion of the MORA survey designed to identify primarily $z>3$ dusty, star-forming galaxies while simultaneously filtering out the more numerous $z<3$ population by leveraging the very negative $K$-correction at observed-frame 2mm. We identify 37 significant ($>$5$\sigma$) sources, 33 of which are robust thermal dust emitters. We measure a median redshift of $\langle z \rangle = 3.6^{+0.1}_{-0.2}$, with two-thirds of the sample at $z>3$, and just under half at $z>4$, demonstrating the overall success of the 2mm-selection technique. The integrated $z>3$ volume density of Ex-MORA sources is $\sim1-3\times10^{-5}$ Mpc$^{-3}$, consistent with other surveys of infrared luminous galaxies at similar epochs. We also find that techniques using rest-frame optical emission (or lack thereof) to identify $z>3$ heavily dust-obscured galaxies miss at least half of Ex-MORA galaxies. This supports the idea that the dusty galaxy population is heterogeneous, and that synergies across observatories spanning multiple energy regimes are critical to understanding their formation and evolution at $z>3$.

At the low-redshift end ($z<0.05$) of the Hubble diagram with Type Ia Supernovae (SNe Ia), the contribution to Hubble residual scatter from peculiar velocities is of similar size to that due to the standardization of the SN Ia light curve. A way to improve the redshift measurement of the SN host galaxy is to utilize the average redshift of the galaxy group, effectively averaging over small-scale/intracluster peculiar velocities. One limiting factor is the fraction of SN host galaxies in galaxy groups, previously found to be 30% using (relatively incomplete) magnitude-limited galaxy catalogs. Here, we do the first analysis of N-body simulations to predict this fraction, finding $\sim$66% should have associated groups and group averaging should improve redshift precision by $\sim$120 km s$^{-1}$. Furthermore, using spectroscopic data from the Anglo-Australian Telescope, we present results from the first pilot program to evaluate whether or not 23 previously unassociated SN Ia hosts belong in groups. We find that 91% of these candidates can be associated with groups, consistent with predictions from simulations given the sample size. Combining with previously assigned SN host galaxies in Pantheon+, we demonstrate improvement in Hubble residual scatter equivalent to 145 km s$^{-1}$, also consistent with simulations. For new and upcoming low-$z$ samples from, for example, the Zwicky Transient Facility and the Rubin Observatory's Legacy Survey of Space and Time, a separate follow-up program identifying galaxy groups of SN hosts is a highly cost-effective way to enhance their constraining power.

We study a magnitude-limited sample of 36 Broad-lined Type Ic Supernovae (SNe Ic-BL) from the Zwicky Transient Facility Bright Transient Survey, detected between March 2018 and August 2021. We present the light curves (LCs) for each of the SNe, and analyze the shape of the LCs to derive empirical parameters, along with the explosion epochs for every event. The sample has an average absolute peak magnitude in the r band of $M_r^{max}$ = -18.51 $\pm$ 0.15 mag. Using spectra obtained around peak light, we compute expansion velocities from the Fe II 5169 Angstrom line for each event with high enough signal-to-noise ratio spectra, and find an average value of $v_{ph}$ = 16,100 $\pm$ 1,100 km $s^{-1}$. We also compute bolometric LCs, study the blackbody temperature and radii evolution over time, and derive the explosion properties of the SNe. The explosion properties of the sample have average values of $M_{Ni}$ = $0.37_{-0.06}^{+0.08}$ solar masses, $M_{ej}$ = $2.45_{-0.41}^{+0.47}$ solar masses, and $E_K$= $4.02_{-1.00}^{+1.37} \times 10^{51}$ erg. Thirteen events have radio observations from the Very Large Array, with 8 detections and 5 non-detections. We find that the populations that have radio detections and radio non-detections are indistinct from one another with respect to their optically-inferred explosion properties, and there are no statistically significant correlations present between the events' radio luminosities and optically-inferred explosion properties. This provides evidence that the explosion properties derived from optical data alone cannot give inferences about the radio properties of SNe Ic-BL, and likely their relativistic jet formation mechanisms.

Radio-frequency interference detection and flagging is one of the most difficult and urgent problems in 21 cm Epoch of Reionization research. In this work, we present $\chi^2$ from redundant calibration as a novel method for RFI detection and flagging, demonstrating it to be complementary to current state-of-the-art flagging algorithms. Beginning with a brief overview of redundant calibration and the meaning of the $\chi^2$ metric, we demonstrate a two-step RFI flagging algorithm which uses the values of this metric to detect faint RFI. We find that roughly 27.4\% of observations have RFI from digital television channel 7 detected by at least one algorithm of the three tested: 18.0\% of observations are flagged by the novel $\chi^2$ algorithm, 16.5\% are flagged by SSINS, and 6.8\% are flagged by AOFlagger (there is significant overlap in these percentages). Of the 27.4\% of observations with detected DTV channel 7 RFI, 37.1\% (10.2\% of the total observations) are detected by $\chi^2$ alone, and not by either SSINS or AOFlagger, demonstrating a significant population of as-yet undetected RFI. We find that $\chi^2$ is able to detect RFI events which remain undetectable to SSINS and AOFlagger, especially in the domain of long-duration, weak RFI from digital television. We also discuss the shortcomings of this approach, and discuss examples of RFI which seems undetectable using $\chi^2$ while being successfully flagged by SSINS and/or AOFlagger.

The escape of LyC photons emitted by massive stars from the dense interstellar medium of galaxies is one of the most significant bottlenecks for cosmological reionization. The escape fraction shows significant scatter between galaxies, and anisotropic, spatial variation within them, motivating further study of the underlying physical factors responsible for these trends. We perform numerical radiation hydrodynamic simulations of idealized clouds with different gas surface densities (compactness) $\Sigma \sim 10^2$--$10^5 \, M_{\odot} \rm{pc}^{-2}$, meant to emulate star cluster-forming clumps ranging from conditions typical of the local Universe to the high ISM-pressure conditions more frequently encountered at high redshift. Our results indicate that dense compact star clusters with $\Sigma \gtrsim 10^4 \, M_{\odot} \rm{pc}^{-2}$ efficiently leak LyC photons, with cloud-scale luminosity-weighted average escape fractions $\gtrsim 80\%$ as opposed to $\lesssim 10\%$ for $\Sigma \sim 100 \, M_{\odot} \rm{pc}^{-2}$. This occurs due to higher star formation efficiencies and shorter dynamical timescales at higher $\Sigma$; the former results in higher intrinsic LyC emission, and the latter implies rapid evolution, with a burst of star formation followed by rapid gas dispersal, permitting high LyC escape well before the intrinsic LyC emission of stellar populations drop ($\sim 4 \, \mathrm{Myr}$). LyC escape in dense clouds is primarily facilitated by highly ionized outflows driven by radiation pressure on dust with velocities $ \sim 3$ times the cloud escape velocity. We also vary the (assumed) dust abundances ($Z_{\rm{d}}$) and find a very mild increase ($\sim 10%$) in the escape fraction for $\sim 100$ lower $Z_{\mathrm{d}}$. Our results suggest a scenario in which localized compact bursts of star formation in galaxies are disproportionately productive sites of LyC leakage.

Mass segregation is seen in many star clusters, but whether massive stars form in the center of a cluster or migrate there dynamically is still debated. N-body simulations have shown that early dynamical mass segregation is possible when sub-clusters merge to form a dense core with a small crossing time. However, the effect of gas dynamics on both the formation and dynamics of the stars could inhibit the formation of the dense core. We aim to study the dynamical mass segregation of star cluster models that include gas dynamics and self-consistently form stars from the dense substructure in the gas. Our models use the Torch framework, which is based on AMUSE and includes stellar and magnetized gas dynamics, as well as stellar evolution and feedback from radiation, stellar winds, and supernovae. Our models consist of three star clusters forming from initial turbulent spherical clouds of mass $10^{4,5,6}\rm~M_\odot$ and radius $11.7\rm~pc$ that have final stellar masses of $3.6\times10^3\rm~M_\odot$, $6.5\times10^4\rm~M_\odot$, and $8.9\times10^5\rm~M_\odot$, respectively. There is no primordial mass segregation in the model by construction. All three clusters become dynamically mass segregated at early times via collapse confirming that this mechanism occurs within sub-clusters forming directly out of the dense substructure in the gas. The dynamics of the embedded gas and stellar feedback do not inhibit the collapse of the cluster. We find that each model cluster becomes mass segregated within $2~$Myr of the onset of star formation, reaching the levels observed in young clusters in the Milky Way. However, we note that the exact values are highly time-variable during these early phases of evolution. Massive stars that segregate to the center during core collapse are likely to be dynamically ejected, a process that can decrease the overall level of mass segregation again.

In spite of their key role in galaxy evolution and several decades of observational efforts, the census of supernova remnants (SNRs) in our Galaxy remains incomplete. Theoretical predictions based on the local supernova rate estimate the expected number of SNRs in the Galaxy to be $\gtrsim$ 1000. By contrast, the number of detected SNRs amounts to about 300. High-resolution, wide-area radio surveys at low frequencies are ideal tools with which to find missing SNRs, given the prominence of these sources at low radio frequencies. We aim to find missing SNRs using proprietary data from the LOFAR Two-Metre Sky Survey (LoTSS) at 144~MHz. We used LoTSS total intensity maps of two Galactic regions, one with $39^\mathrm{o} < l < 66^\mathrm{o}$ and $|b|< 2.5^\mathrm{o}$, and the other with $145^\mathrm{o} < l < 150^\mathrm{o}$ and $|b| < 3^\mathrm{o}$, in addition to mid-infrared (MIR) data from the Wide-field Infrared Survey Explorer (WISE) all-sky survey to search for SNR candidates. We report the discovery of 14 new SNR candidates selected on the basis of their morphology at 144 MHz and a lack of MIR emission. We also follow up on 24 previously reported SNR candidates, inferring their spectral index between the LoTSS frequency (144 MHz) and the frequency at which they were reported. The high resolution and sensitivity of LoTSS observations has resulted in the detection of 14 new SNR candidates. In order to unambiguously confirm the SNR nature of these candidates, follow-up X-ray observations are required with facilities such as eROSITA.

Solar-type stars have been observed to flare at optical wavelengths to energies much higher than observed for the Sun. To date, no counterparts have been observed at longer wavelengths. We have searched the the VLA Sky Survey (VLASS) for radio emission associated with a sample of 150 single, solar-type stars previously been observed to exhibit superflares in the Transiting Exoplanet Survey Satellite (TESS). Counterparts to six of these stars were present in VLASS as transient or highly variable radio sources. One of the stars is detected in all three epochs, exhibiting an unprecedented level of apparently persistent radio emission. The engine for this radio emission is unclear, but may be related to accretion, a binary companion, or the presence of large-scale magnetic field. Two stars show radio emission with >50 circular polarization fraction, indicating a coherent emission process likely being present. We find that the six VLASS-detected stars tend to have higher flare rates and higher flare energies of our TESS sample. This, in addition to the VLASS-detected stars adhering to the Gudel-Benz relation, suggest that the radio emission may be directly associated with superflares. These results confirm that the superflare phenomenon on solar-type stars extends to radio wavelengths, in this instance tracing particle acceleration. These data provide the first window on the luminosity function of radio superflares for solar-type stars and highlights the need for coordinated, multi-wavelength monitoring of such stars to fully illustrate the stellar flare-particle relation.

Baryonic Acoustic Oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI), in combination with Cosmic Microwave Background (CMB) data and Type Ia Supernovae (SN) luminosity distances, suggests a dynamical evolution of the dark energy equation of state with a phantom phase ($w < -1$) in the past when the so-called $w_0w_a$ parametrization $w(a) = w_0 + w_a(1-a)$ is assumed. In this work, we investigate more general dark energy models that also allow a phantom equation of state. We consider three cases: an equation of state with a transition feature, a model-agnostic equation of state with constant values in chosen redshift bins, and a k-essence model. Since the dark energy equation of state is correlated with neutrino masses, we reassess constraints on the neutrino mass sum focusing on the model-agnostic equation of state. We find that the combination of DESI BAO with Planck 2018 CMB data and SN data from Pantheon, Pantheon+, or Union3 is consistent with an oscillatory dark energy equation of state, while a monotonic behavior is preferred by the DESY5 SN data. Performing model comparison techniques, we find that the $w_0w_a$ parametrization remains the simplest dark energy model that can provide a better fit to DESI BAO, CMB, and all SN datasets than $\Lambda$CDM. Constraints on the neutrino mass sum assuming dynamical dark energy are relaxed compared to $\Lambda$CDM and we show that these constraints are tighter in the model-agnostic case relative to $w_0w_a$ model by $70\%-90\%$.

H$_2$O$_2$ is part of Europa's water-ice radiolytic cycle and a potential source of oxidants to Europa's subsurface ocean. However, factors controlling the concentration of this critical surface species remain unclear. Though laboratory experiments suggest that Europa's H$_2$O$_2$ should be concentrated in the coldest, most ice-rich regions toward the poles, Keck adaptive optics observations have shown the strongest H$_2$O$_2$ signatures in comparatively warm, salt-bearing terrain at low latitudes. As a result, it was suggested that the local non-ice composition of these terrains -- particularly hypothesized enrichments of CO$_2$ -- may be a more dominant control on H$_2$O$_2$ than temperature or water-ice abundance. Here, we use observations of Europa from the NASA Infrared Telescope Facility, Keck Observatory, and JWST to disentangle the potential effects of temperature and composition. In order to isolate the effect of temperature on Europa's H$_2$O$_2$, we use the ground-based observations to assess its response to temperature changes over timescales associated with Europa's daily eclipse and diurnal cycle. We use JWST Cycle 1 data to look for any geographic correlation between Europa's H$_2$O$_2$ and CO$_2$. Both changes in Europa's 3.5-$\mu$m H$_2$O$_2$ absorption band from pre to post eclipse and across a local day suggest minimal effects of the local temperature on these timescales. In contrast, the JWST observations show a strong positive correlation between Europa's H$_2$O$_2$ and CO$_2$ bands, supporting the previously suggested possibility that the presence of CO$_2$ in the ice may enhance H$_2$O$_2$ concentrations via electron-scavenging.

We present X-ray to radio frequency observations of the bright long gamma-ray burst GRB 210702A. Our ALMA 97.5 GHz observations show a significant rebrightening by a factor of ~2 beginning at 8.2 days post-burst and rising to peak brightness at 18.1 days before declining again. This is the first such rebrightening seen in a millimeter afterglow light curve. A standard forward shock model in a stellar wind circumburst medium can explain most of our X-ray, optical and millimeter observations prior to the rebrightening, but significantly over-predicts the self-absorbed radio emission, and cannot explain the millimeter rebrightening. We investigate possible explanations for the millimeter rebrightening and find that energy injection or a reverse shock from a late-time shell collision are plausible causes. Similar to other bursts, our radio data may require alternative scenarios such as a thermal electron population or a structured jet to explain the data. Our observations demonstrate that millimeter light curves can exhibit some of the rich features more commonly seen in optical and X-ray afterglow light curves, motivating further millimeter wavelength studies of GRB afterglows.

We present the design and first results of the Inner Circumgalactic Medium (CGM) of QSO Line of Sight Emitting galaxies at $z\sim 2-3$, KBSS-InCLOSE. The survey will connect galaxy properties (e.g., stellar mass $M_*$, interstellar medium ISM metallicity) with the physical conditions of the inner CGM (e.g., kinematics, metallicity) to directly observe the galaxy-scale baryon cycle. We obtain deep Keck/KCWI optical IFU pointings of Keck Baryonic Structure Survey (KBSS) QSOs to discover new star-forming galaxies at small projected distances $b\lesssim12"$ (98 kpc, $\overline{z}=2.3$), then obtain follow-up Keck/MOSFIRE NIR spectra to confirm their redshifts. We leverage KBSS images and Keck/HIRES QSO spectra to model stellar populations and inner CGM absorption. In this paper, we analyze two QSO fields and discover more than 15 new galaxies with KCWI, then use MOSFIRE for two galaxies Q2343-G1 ($z=2.43$; G1) and Q2233-N1 ($z=3.15$; N1), which are both associated with Damped Lyman Alpha absorbers. We find that G1 has typical $M_*$,UV/optical emission properties. N1 has lower $M_*$ with very strong nebular emission. We jointly analyze neutral phase CGM and ionized ISM in N/O (for the first time at this $z$), dust extinction, and high-ionization CGM finding that: G1's CGM is metal poor and less evolved than its ISM, while N1's CGM and ISM abundances are comparable; their CGM shows $\sim1$ dex less dust extinction than the ISM; and G1's CGM has direct evidence of hot, metal-rich galactic outflow ejecta. These findings support that metals and dust are driven into the CGM from outflows, but may also be e.g., stripped ISM gas or satellite enrichment. The full KBSS-InCLOSE sample will explore these scenarios.

In the absence of laboratory data, state-of-the-art quantum chemical approaches can provide estimates on the binding energy (BE) of interstellar species with grains. Without BE values, contemporary astrochemical models are compelled to utilize wild guesses, often delivering misleading information. Here, we employ a fully quantum chemical approach to estimate the BE of 7 diatomic radicals - CH, NH, OH, SH, CN, NS, and NO, playing a crucial role in shaping the interstellar chemical composition, using a suitable amorphous solid water model as a substrate since water is the principal constituent of interstellar ice in dense and shielded regions. While the BEs are compatible with physisorption, the binding of CH in some sites shows chemisorption, in which a chemical bond to an oxygen atom of a water molecule is formed. While no structural change can be observed for the CN radical, it is believed that the formation of a hemibonded system between the outer layer of the water cluster and the radical is the reason for the unusually large BE in one of the binding sites considered in our study. A significantly lower BE for NO, consistent with recent calculations, is obtained, which is useful in explaining the recently observed HONO/NH2OH and HONO/HNO ratio in the low-mass hot corino, IRAS 16293-2422B, with chemical models.

Transiting giant exoplanets around M-dwarf stars (GEMS) are rare, owing to the low-mass host stars. However, the all-sky coverage of TESS has enabled the detection of an increasingly large number of them to enable statistical surveys like the \textit{Searching for GEMS} survey. As part of this endeavour, we describe the observations of six transiting giant planets, which includes precise mass measurements for two GEMS (K2-419Ab, TOI-6034b) and statistical validation for four systems, which includes validation and mass upper limits for three of them (TOI-5218b, TOI-5616b, TOI-5634Ab), while the fourth one -- TOI-5414b is classified as a `likely planet'. Our observations include radial velocities from the Habitable-zone Planet Finder on the Hobby-Eberly Telescope, and MAROON-X on Gemini-North, along with photometry and high-contrast imaging from multiple ground-based facilities. In addition to TESS photometry, K2-419Ab was also observed and statistically validated as part of the K2 mission in Campaigns 5 and 18, which provides precise orbital and planetary constraints despite the faint host star and long orbital period of $\sim 20.4$ days. With an equilibrium temperature of only 380 K, K2-419Ab is one of the coolest known well-characterized transiting planets. TOI-6034 has a late F-type companion about 40\arcsec~away, making it the first GEMS host star to have an earlier main-sequence binary companion. These confirmations add to the existing small sample of confirmed transiting GEMS.

This paper presents the global analysis of two extended decreases of the galactic cosmic ray intensity observed by world-wide networks of ground-based detectors in 2012. This analysis is capable of separately deriving the cosmic ray density (or omnidirectional intensity) and anisotropy each as a function of time and rigidity. A simple diffusion model along the spiral field line between Earth and a cosmic-ray barrier indicates the long duration of these events resulting from about 190$^\circ$ eastern extension of a barrier such as an IP-shock followed by the sheath region and/or the corotating interaction region (CIR). It is suggested that the coronal mass ejection merging and compressing the preexisting CIR at its flank can produce such the extended barrier. The derived rigidity spectra of the density and anisotropy both vary in time during each event period. In particular we find that the temporal feature of the ``phantom Forbush decrease'' reported in an analyzed period is dependent on rigidity, looking quite different at different rigidities. From these rigidity spectra of the density and anisotropy, we derive the rigidity spectrum of the average parallel mean-free-path of pitch angle scattering along the spiral field line and infer the power spectrum of the magnetic fluctuation and its temporal variation. Possible physical cause of the strong rigidity dependence of the ``phantom Forbush decrease'' is also discussed. These results demonstrate the high-energy cosmic rays observed at Earth responding to remote space weather.

If dark matter (DM) accumulates inside neutron stars (NS), it changes their internal structure and causes a shift of the tidal deformability from the value predicted by the dense-matter equation of state (EOS). In principle, this shift could be observable in the gravitational-wave (GW) signal of binary neutron star (BNS) mergers. We investigate the effect of fermionic, non-interacting DM when observing a large number of GW events from DM-admixed BNSs with the precision of the proposed Einstein telescope (ET). Specifically, we study the impact on the recovery of the baryonic EOS and whether DM properties can be constrained. For this purpose, we create event catalogues of BNS mock events with DM fraction up to 1%, from which we reconstruct the posterior uncertainties with the Fisher matrix approach. Using this data, we perform joint Bayesian inference on the baryonic EOS, DM particle mass, and DM particle fraction in each event. Our results reveal that when falsely ignoring DM effects, the EOS posterior is biased towards softer EOSs, though the offset is rather small. Further, we find that within our assumptions of our DM model and population, ET will likely not be able to test the presence of DM in BNSs, even when combining many events and adding Cosmic Explorer (CE) to the next-generation detector network. Likewise, the potential constraints on the DM particle mass will remain weak because of degeneracies with the fraction and EOS.

High-energy photons of gamma-ray bursts (GRBs) might be emitted at different intrinsic times with energy dependence at the source. In this letter, we expand the model from previous works on testing the Lorentz Invariance Violation (LV) with the observed GRB data from the Fermi Gamma-ray Space Telescope. We reanalyze the previous data with the full Bayesian parameter estimation method and get consistent results by assuming that the time delays are due to an LV term and a constant intrinsic time delay term. Subsequently, we neglect the LV effect and only consider the intrinsic time delay effect. We assume a common intrinsic time delay term along with a source energy correlated time delay of high-energy photons. We find that the energy-dependent emission times can also explain the observed GRB data of high-energy photon events. Finally, we integrate these two physical mechanisms into a unified model to distinguish and evaluate their respective contributions using the observed GRB data.

The paper addresses the possibility of a young Mars having had a massive moon, which synchronised the rotation of Mars, and gave Mars an initial asymmetric triaxiality to be later boosted by geological processes. It turns out that a moon of less than a third of the lunar mass was capable of producing a sufficient initial triaxiality. The asymmetry of the initial tidal shape of the equator depends on timing: the initial asymmetry is much stronger if the synchronous moon shows up already at the magma-ocean stage. From the moment of synchronisation of Mars' rotation with the moon's orbital motion, and until the moon was eliminated (as one possibility, by an impact in the beginning of the LHB), the moon was sustaining an early value of Mars' rotation rate.

The response tensor is derived for a relativistically streaming, strongly magnetized, one-dimensional Jüttner distribution of electrons and positrons, referred to as a pulsar plasma. This is used to produce a general treatment of wave dispersion in a pulsar plasma. Specifically, relativistic streaming, the spread in Lorentz factors in a pulsar rest frame, and cyclotron resonances are taken into account. Approximations to the response tensor are derived by making approximations to relativistic plasma dispersion functions appearing in the general form of the response tensor. The cold-plasma limit, the highly relativistic limit, and limits related to cyclotron resonances are considered. The theory developed in this paper has applications to generalised Faraday rotation in pulsars and magnetars.

We present a population synthesis model for normal radio pulsars in the Galaxy incorporating the latest developments in the field and the magnetorotational evolution processes. Our model considers spin-down with a force-free magnetosphere and the decay of the magnetic field strength and its inclination angle. The simulated pulsar population is fit to a large observation sample that covers the majority of radio surveys using the Markov Chain Monte Carlo technique. We compare the distributions of four major observables: spin period (P), spin down rate($\dot{P}$), dispersion measure, and radio flux density using accurate high-dimensional Kolmogoro-Smirnov statistics. We test two B-field decay scenarios, an exponential model motivated by ohmic dissipation and a power-law model motivated by the Hall effect. The former clearly provides a better fit, and it can successfully reproduce the observed pulsar distributions with a decay timescale of $8.3_{-3.0}^{+3.9}$ Myr. The result suggests that significant B-field decay in aged pulsars and ohmic dissipation could be the dominant process.

We parameterize the equation of state of late-time dark energy as $w_{\mathrm{bin}}(z)$, with three redshift bins, characterized by a constant equation of state in each bin. Then, we constrain the parameters of the $w_{\mathrm{bin}}$CDM model using datasets from DESI BAO data, Planck CMB power spectrum, ACT DR6 lensing power spectrum, and type Ia supernova distance-redshift data of Pantheon Plus/DES Y5/Union3. The significances for $w_1>-1$ is $1.9\sigma$, $2.6\sigma$ and $3.3\sigma$, and $w_2$ is consistent with $-1$ within $1\sigma$ level, while $1.6\sigma$, $1.5\sigma$ and $1.5\sigma$ for $w_3<-1$ in these three data combinations with different choices of type Ia supernova datasets, respectively. Additionally, to alleviate $H_0$ tension, we incorporate the early dark energy (EDE) model in the early-time universe and add the SH0ES absolute magnitude $M_b$ prior (or $H_0$ prior) to further constrain the $w_{\mathrm{bin}}$EDE model. In the $w_{\mathrm{bin}}$EDE model, we find a $w_{\mathrm{bin}}(z)$ pattern similar to that in the $w_{\mathrm{bin}}$CDM model. The results of the three data combinations exhibit $w_1>-1$ at $1.9\sigma$, $1.7\sigma$ and $2.9\sigma$ level, meanwhile $w_3<-1$ at $1.3\sigma$, $1.3\sigma$ and $1.3\sigma$ level, respectively. In all, our results indicate that the transition of dark energy from phantom at high redshifts to quintessence at low redshifts is not conclusive.

Direct redshift determination of BL Lac objects is highly challenging as the emission in the optical and near-infrared (NIR) bands is largely dominated by the non-thermal emission from the relativistic jet that points very close to our line of sight. Therefore, their optical spectra often show no emission lines from the host galaxy. In this work, we aim to overcome this difficulty by attempting to detect the host galaxy and derive redshift constraints based on assumptions on the galaxy magnitude ("imaging redshifts"). Imaging redshifts are derived by obtaining deep optical images under good seeing conditions, so that it is possible to detect the host galaxy as weak extension of the point-like source. We then derive the imaging redshift by using the host galaxy as a standard candle using two different methods. We determine imaging redshift for 9 out of 17 blazars that we observed as part of this program. The redshift range of these targets is 0.28-0.60 and the two methods used to derive the redshift give very consistent results within the uncertainties. We also performed a detailed comparison of the imaging redshifts with those obtained by other methods, like direct spectroscopic constraints or looking for groups of galaxies close to the blazar. We show that the constraints from different methods are consistent and that for example in the case of J2156.0+1818, which is the most distant source for which we detect the host galaxy, combining the three constraints narrows down the redshift to $0.63<z<0.71$. This makes the source interesting for future studies of extragalactic background light in the Cherenkov Telescope Array Observatory era.

Nanosatellites are proliferating as low-cost dedicated sensing systems with lean development cycles. Kyushu Institute of Technology and collaborators have launched a joint venture for a nanosatellite mission, VERTECS. The primary mission is to elucidate the formation history of stars by observing the optical-wavelength cosmic background radiation. The VERTECS satellite will be equipped with a small-aperture telescope and a high-precision attitude control system to capture the cosmic data for analysis on the ground. However, nanosatellites are limited by their onboard memory resources and downlink speed capabilities. Additionally, due to a limited number of ground stations, the satellite mission will face issues meeting the required data budget for mission success. To alleviate this issue, we propose an on-orbit system to autonomously classify and then compress desirable image data for data downlink prioritization and optimization. The system comprises a prototype Camera Controller Board (CCB) which carries a Raspberry Pi Compute Module 4 which is used for classification and compression. The system uses a lightweight Convolutional Neural Network (CNN) model to classify and determine the desirability of captured image data. The model is designed to be lean and robust to reduce the computational and memory load on the satellite. The model is trained and tested on a novel star field dataset consisting of data captured by the Sloan Digital Sky Survey (SDSS). The dataset is meant to simulate the expected data produced by the 6U satellite. The compression step implements GZip, RICE or HCOMPRESS compression, which are standards for astronomical data. Preliminary testing on the proposed CNN model results in a classification accuracy of about 100\% on the star field dataset, with compression ratios of 3.99, 5.16 and 5.43 for GZip, RICE and HCOMPRESS that were achieved on tested FITS image data.

The POEMMA-Balloon with Radio (PBR) is a proposed payload to fly on a NASA Super Pressure Balloon (SPB). It will act as a pathfinder of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) detector. PBR will consist of an innovative hybrid focal surface featuring a Fluorescence Camera (FC, based on Multi-Anode Photomultiplier Tubes [MAPMTs], 1.05 $\mu$s time resolution) and a Cherenkov Camera (based on SiPMs, 10 ns time resolution), both mounted on the same tiltable frame that can point from nadir up to 13$^\circ$ above the horizon. The FC's main scientific goal is to observe, for the first time, the fluorescence emission of Extensive Air Showers produced by Ultra-High Energy Cosmic Rays from sub-orbital altitudes. This measurement will validate the detection strategy for future space-based missions, such as POEMMA. As a secondary goal, the FC will perform a search for macroscopic dark matter through slowly evolving showers that will leave a signal similar to (but distinct from) a meteor. PBR targets a launch in 2027 as a payload of an ultra-long duration balloon flight with a duration of up to 100 days.

We utilized a sample from the Fermi-LAT 14-year Source Catalog by adjusting the flux detection threshold, enabling us to derive the intrinsic source count distribution $dN/dF_{25}$ of extragalactic blazars using nonparametric, unbinned methods developed by Efron and Petrosian and Lynden-Bell. Subsequently, we evaluated the contribution of blazars to the extragalactic gamma-ray background. Our findings are summarized as follows: (1) There is no significant correlation between flux and spectral index values among blazars and their subclasses FSRQs and BL Lacs. (2) The intrinsic differential distributions of flux values exhibit a broken-power-law form, with parameters that closely match previous findings. The intrinsic photon index distributions are well described by a Gaussian form for FSRQs and BL Lacs individually, while a dual-Gaussian model provides a more appropriate fit for blazars as a whole. (3) Blazars contribute 34.5\% to the extragalactic gamma-ray background and 16.8\% to the extragalactic diffuse gamma-ray background. When examined separately, FSRQs and BL Lacs contribute 19.6\% and 13\% to the extragalactic gamma-ray background, respectively.

Preheating at the end of inflation is a violent nonlinear process that efficiently transfers the energy of the inflaton to a second field, the preheat field. When the preheat field is light during inflation and its background value modulates the preheating process, the superhorizon isocurvature perturbations of the preheat field may be converted to curvature perturbations that leave an imprint on the cosmic microwave background and the large-scale structure of the universe. We use high-precision lattice simulations to study kinetic preheating after $\alpha$-attractor inflation, a case where the effective mass of the preheat field is naturally suppressed during inflation. By comparing the expansion e-folds between different Hubble patches, we find that the conversion from isocurvature perturbations to curvature perturbations is very inefficient and can hardly be detected by cosmological observations.

By adopting the recently empirically derived dependence of $\alpha$-elements on $[\alpha/{\rm Fe}]$ instead of the conventionally applied uniform one, we tested the agreement between stellar model predictions and observations for red giant branch (RGB) stars in the APO-K2 catalogue. We particularly focused on the biases in effective temperature scales and on the robustness of age estimations. We computed a grid of stellar models relying on the empirical scaling of $\alpha$-elements, investigating the offset in effective temperature $\Delta T$ between these models and observations, using univariate analyses for both metallicity [Fe/H] and $[\alpha/{\rm Fe}]$. To account for potential confounding factors, we then employed a multivariate generalised additive model to study the dependence of $\Delta T$ on [Fe/H], $[\alpha/{\rm Fe}]$, $\log g$, and stellar mass. The initial analysis revealed a negligible trend of $\Delta T$ with [Fe/H], in contrast with previous works in the literature. A slight $\Delta T$ difference of 25 K was detected between stars with high and low $\alpha$-enhancement. Our multivariate analysis reveals a dependence of $\Delta T$ on both [Fe/H] and $[\alpha/{\rm Fe}]$, and highlights a significant dependence on stellar mass. This suggests a discrepancy in how effective temperature scales with stellar mass in the models compared to observations. Despite differences in assumed chemical composition, our analysis, through a fortunate cancellation effect, yields ages that are largely consistent with recent studies of the same sample. Notably, our analysis identifies a 6% fraction of stars younger than 4 Ga within the high-$\alpha$ population. However, our analysis of the [C/N] ratio supports the possible origin of the these stars as a result of mergers or mass transfer events.

Detecting mid-infrared (MIR) radiation has significant astronomical applications, although limited by unsatisfactory MIR detectors. Here we reported on the realization of a MIR up-conversion interferometer based on synthetic long base-line (SLBL) in the laboratory. The experimental system consisted of an interferometer and subsequent up-conversion detection part of mid-infrared signal, which streamlined the structure and enhanced the reliability of the system. By using a tungsten filament lamp as an imitated star, we not only achieved the single target angle resolution of 1.10 times 10^(-4) rad, but also obtained the field angle resolution of 3.0 times 10^(-4) rad of double star targets. The angular resolution is in inverse proportion to the length of baseline. The maximum length of simulated baseline in the laboratory is about 3cm. In a Keck Interferometer (KI) liked program, the base line can reach up to 85m leading to a corresponding angular resolution of 3.0 times 10^(-9) rad (about 1.8mas). The study will offer potential benefits in extending the usage of mid-infrared light in astronomical exploration.

The study of the continuum radiative transfer problem inside circumstellar envelopes is both a theoretical and numerical challenge, especially in the frequency-dependent and multi-dimensional case. While approximate methods are easier to handle numerically, they often fail to accurately describe the radiation field inside complex geometries. For these cases, it is necessary to directly solve numerically the radiative transfer equation. We investigate the accuracy of a discontinuous Galerkin finite element method (DGFEM hereafter) applied to the frequency-dependent two dimensional radiative transfer equation, coupled with the radiative equilibrium equation, inside axis-symmetric circumstellar envelopes. The DGFEM is a variant of finite element methods. It employs discontinuous elements and flux integrals along their boundaries, ensuring local conservation. However, as opposed to the classical finite-element methods, the solution is discontinuous across element edges. We implemented the method in a code and tested its accuracy by comparing our results with the benchmarks from the literature. For all the tested cases, the temperature profile agrees within one percent. Additionally, the emerging spectral energy distributions (SEDs) and images, obtained subsequently by ray-tracing techniques from the DGFEM solution, agree on average within $5~\mathrm{\%}$ and $10~\mathrm{\%}$, respectively. We show that the DGFEM can accurately describe the temperature profile inside axis-symmetric circumstellar envelopes. Consecutively the emerging SEDs and images are also well reproduced. The discontinuous Galerkin finite element method provides an alternative method (other than Monte Carlo methods for instance) for solving the radiative transfer equation, and could be used in cases that are more difficult to handle with the other methods.

We present an overview of the operations and engineering interface for Planetary Radio Interferometry and Doppler Experiment (PRIDE) radio astronomy observations as a scientific component of the ESA s Jupiter Icy Moons Explorer (JUICE) mission, as well as other prospective planetary and space science missions. The article discusses advanced scheduling and planning methods that make it possible to create observing schedules for observations of specific spacecraft in concurrence with observations of natural radio sources. In order to put this into practice and find suitable natural background calibrator sources for PRIDE of JUICE mission, we developed planning and scheduling software. The conventional scheduling software for natural celestial radio sources is not set up to include spacecraft as observation targets in the necessary control files. Therefore, difficulties already arise during observation planning. We report on the development of new and the adaptation of existing routines used in astrophysical and geodetic VLBI for satellite scheduling and planning. The analysis of the PRIDE science observations led to improved observational planning, and the mission s scheduling methodologies were studied using a systems engineering approach. In addition, we highlighted the new procedures, like finding charts for selecting calibrator radio sources over a range of frequency bands and the outcomes of those strategies for science operation planning. A simulation of the flyby of Venus during the cruise phase of the JUICE spacecraft, based on the Tudat software, is also presented, resulting in a promising opportunity to test PRIDE techniques and evaluate the improvements that PRIDE observables can make to natural bodies ephemerides.

Coronal mass ejections (CMEs) are complex magnetized plasma structures in which the magnetic field spirals around a central axis, forming what is known as a flux rope (FR). The central FR axis can be oriented at any angle to the ecliptic. Throughout its journey, a CME will encounter interplanetary magnetic field and solar wind which are neither homogeneous nor isotropic. Consequently, CMEs with different orientations will encounter different ambient medium conditions and, thus, the interaction of a CME with its surrounding environment will vary depending on the orientation of its FR axis, among other factors. This study aims to understand the effect of inclination on CME propagation. We performed simulations with the EUHFORIA 3D magnetohydrodynamic model. This study focuses on two CMEs modelled as spheromaks with nearly identical properties, differing only by their inclination. We show the effects of CME orientation on sheath evolution, MHD drag, and non-radial flows by analyzing the model data from a swarm of 81 virtual spacecraft scattered across the inner heliospheric. We have found that the sheath duration increases with radial distance from the Sun and that the rate of increase is greater on the flanks of the CME. Non-radial flows within the studied sheath region appear larger outside the ecliptic plane, indicating a "sliding" of the IMF in the out-of ecliptic plane. We found that the calculated drag parameter does not remain constant with radial distance and that the inclination dependence of the drag parameter can not be resolved with our numerical setup.

We consider the Chern-Simons term coupled to the inflaton in the Palatini formulation of general relativity. In contrast to the metric formulation, here the Chern-Simons term affects also the background evolution. We approximately solve for the connection, insert it back into the action, and reduce the order of the equations to obtain an effective theory in the gradient approximation. We consider three cases: when the connection is unconstrained, and when non-metricity or torsion is put to zero. In the first two cases, the inflaton kinetic term is modified with a term proportional to the square of the potential. For polynomial potentials dominated by the highest power of the field, the Chern-Simons term solves the problem that higher order corrections spoil the flatness of the potential. For Higgs inflation, the tensor-to-scalar ratio can as large as the current observational bound, and the non-minimal coupling to the Ricci scalar can be as small as in the metric case. The Palatini contribution cures the known instability of the tensor modes due the Chern-Simons term in the metric formulation.

This special issue of the Astroparticle Physics journal is dedicated to the memory of Thomas Korff Gaisser, the Martin A. Pomerantz Professor Emeritus of Physics at the University of Delaware. Tom was one of the most prominent scientists in cosmic-ray and astroparticle physics, and also one of the founding editors of this very journal. A theoretical particle physicist by training, he dedicated his career to cosmic-ray physics. He worked on the phenomenology of high-energy particle interactions in the atmosphere, modeling extensive air showers, including the famous 'Gaisser-Hillas' function describing their longitudinal profile. A focus of his work were muon and neutrino fluxes resulting from cosmic-ray showers in the atmosphere, and their measurement with specialized experiments at the South Pole.

The aim of this work is to characterize the accretion process of the classical T Tauri Star RU Lup. We studied optical high-resolution spectroscopic observations from CHIRON and ESPRESSO, obtained simultaneously with photometric data from AAVSO and TESS. We detected a periodic modulation in the narrow component of the He I 5876 line with a period that is compatible with the stellar rotation period, indicating the presence of a compact region on the stellar surface that we identified as the footprint of the accretion shock. We show that this region is responsible for the veiling spectrum, which is made up of a continuum component plus narrow line emission. An analysis of the high-cadence TESS light curve reveals quasi-periodic oscillations on timescales shorter than the stellar rotation period, suggesting that the accretion disk in RU~Lup extends inward of the corotation radius, with a truncation radius at $\sim 2 ~ R_{\star}$. This is compatible with predictions from three-dimensional magnetohydrodynamic models of accretion through a magnetic boundary layer (MBL). In this scenario, the photometric variability of RU Lup is produced by a nonstationary hot spot on the stellar surface that rotates with the Keplerian period at the truncation radius. The analysis of the broad components of selected emission lines reveals the existence of a non-axisymmetric, temperature-stratified flow around the star, in which the gas leaves the accretion disk at the truncation radius and accretes onto the star channeled by the magnetic field lines. The unusually rich metallic emission line spectrum of RU Lup might be characteristic of the MBL regime of accretion. In conclusion, the behavior of RU Lup reveals many similarities to predictions from the MBL accretion scenario. Alternative explanations would require the existence of a hot spot with a complex shape, or a warped structure in the inner disk.

The physical trigger powering supernovae following the core collapse of massive stars is believed to involve a neutron star (NS) or a black hole (BH), depending largely on progenitor mass. A potentially distinct signature is a long-duration gravitational wave (GW) burst from BH central engines by their ample energy reservoir $E_J$ in angular momentum, far more so than an NS can provide. A natural catalyst for this radiation is surrounding high-density matter in the form of a non-axisymmetric disk or torus. Here, we derive a detailed outlook on LVK probes of core-collapse supernovae CC-SNe during the present observational run O4 based on their event rate, an association with normal long GRBs and mass-scaling of GW170817B/GRB170817A. For BH central engines of mass $M$, GW170817B predicts a descending GW-chirp of energy ${\cal E}_{GW}\simeq 3.5\% M_\odot c^2 \left(M/M_0\right)$ at frequency $f_{GW}\lesssim 700\,{\rm Hz}\left(M_0/M\right)$, where $M_0\simeq 2.8\,M_\odot$. For a few tens of events per year well into the Local Universe within 50-100Mpc, probes at the detector-limited sensitivity are expected to break the degeneracy between their NS or BH central engines {by GW calorimetry.

Pulsar glitch is a phenomenon characterized by abrupt changes in the spin period over less than a minute. We present a comprehensive analysis of glitches in four gamma-ray pulsars by combining the timing observation data of \textit{Fermi} Large Area Telescope (\textit{Fermi}-LAT) and Parkes 64 m radio telescope. The timing data of five pulsars, namely PSRs J1028$-$5819, J1420$-$6048, J1509$-$5850, J1709$-$4429 (B1706$-$44) and J1718$-$3825, spanning over 14 years of observations for each, are examined. A total of 12 glitches are identified in four pulsars, including a previously unreported glitch. That is, a new small glitch is identified for PSR J1718$-$3825 in MJD $\sim$ 59121(8), and the fractional glitch size was $\Delta \nu/\nu \sim 1.9(2) \times 10^{-9}$. For PSR J1420$-$6048, our investigation confirms the existence of two linear recovery terms during the evolution of $\dot{\nu}$ subsequent to glitches 4, 6 and 8, and identified an exponential recovery process in glitch 8, with $Q = 0.0131(5)$, $\tau_{\rm d} = 100(6)$ d. Regarding the fourth glitch of PSR J1709$-$4429, our analysis reveals the presence of two exponential recovery terms with healing parameters and decay time-scales $Q$1=0.0104(5), $\tau_{\rm d1}=72(4)$ d and $Q$2 = 0.006(1), $\tau_{\rm d2}=4.2(6)$ d, respectively. For the remaining previously reported glitches, we refine the glitch epochs and glitch observables through precise fitting of the timing residual data. We extensively discuss how multi-band data of glitches can help better characterize the glitch recoveries and constrain the underlying physics of glitch events. We demonstrate that the accumulation of observational data reveals the rich complexity of the glitch phenomenon, aiding in the search for a well-established interpretation.

The vast majority of the orbital population today is unobservable and untracked because of their small size. These lethal non-trackable objects will only become more numerous as more payloads and debris are launched into orbit and increase the collision rate. In this paper, the long-term effect of collisions is simulated with an efficient Monte-Carlo method to simulate the future LEO environment including lethal non-trackable objects, which is typically ignored due to the large computational resources required. The results show that simulations that do not incorporate lethal non-trackable debris would be omitting a large number of debilitating collisions with active payloads and catastrophic collisions to a smaller effect. This shows the importance of simulating small debris in the long-term evolution of the orbital population, which is often omitted in the literature. This increased debris population and consequentially the risk to orbital payloads diminishes as smaller lethal non-trackable objects are considered. An efficient and validated model is used to simulate these numerous small objects. Several future cases such as launches of registered megaconstellations, improved post-mission disposal rates and no-future launches are explored to understand the effect of the inclusion or exclusion of lethal non-trackable objects.

We present FitTeD, a public light curve and spectral fitting Python-package based on evolving relativistic discs. At its heart this package uses the solutions of the time dependent general relativistic disc equations to compute multi-band light curves and spectra. All relevant relativistic optics effects (Doppler and gravitational energy shifting, and gravitational lensing) are included. Additional, non-disc light curve and spectral components can be included to (for example) model the early time rise and decay of tidal disruption event light curves in optical-to-UV bands. Monte Carlo Markov Chain fitting procedures are included which return posterior distributions of black hole and disc parameters, allowing for the future automated processing of the large populations of transient sources discovered by (e.g.,) the Vera Rubin Observatory. As an explicit example, in this paper we model the multi-wavelength light curves of the tidal disruption event AT2019dsg, finding a good fit to the data, a black hole mass consistent with galactic scaling relationships, and a late-time disc Eddington ratio consistent with the observed launching of an outflow observed in radio bands.

In the present study we employ three distinct physically motivated speed of sound bounds in order to construct hybrid models where the high density phase is described by the maximally stiff equation of state. In particular, we consider the bounds related to special relativity, relativistic kinetic theory and conformality. The low density hadronic phase is described by a state-of-the-art microscopic relativistic Brueckner-Hartree-Fock theory. This work aims to access the effect of the different speed of sound constraints on the relevant parameter space of the key parameters of first-order phase transitions by utilising recent astronomical data. This involves a systematic analysis that also includes two distinct schemes for the construction of hybrid models, namely the Maxwell and Gibbs methods. Finally, a relevant discussion is conducted on the possible occurrence of a thermodynamic inconsistency that is related to the stability of the high density phase over hadronic matter at large densities.

Sixty years after the discovery of brown dwarfs, the search for these objects continues, particularly in the vicinity of the Sun. Objects near the Sun are characterized by large proper motions, making them seen as fast-moving objects. While the Gaia DR3 catalogue is a comprehensive source of proper motions, it lacks the depth needed for discovering fainter objects. Modern multi-epoch surveys, with their greater depth, offer a new opportunity for systematic search for ultra-cool dwarfs. The study aims to systematically search for high proper motion objects using the newly released catalogue of epochal WISE data in order to identify new brown dwarf candidates in the solar neighborhood, estimate their spectral types, distances and spatial velocities. We used recently released unTimely catalogue of epochal detections in unWISE coadds to search for objects with high proper motions using simple motion detection algorithm. This method was used to identify objects with proper motions exceeding approximately 0.6 arcseconds per year. The identified objects were then cross-referenced with data from other large-scale sky surveys to further analyze their characteristics. The search yielded 3245 moving objects with significant proper motions, 32 of which had not been previously published. Among these, at least 15 were identified as reliable new brown dwarf candidates, with estimated distances closer than 50 parsecs and spectral types later than T0.

Hydrogen-rich superluminous supernovae (SLSNe II) are rare. The exact mechanism producing their extreme light curve peaks is not understood. Analysis of single events and small samples suggest that CSM interaction is the main responsible for their features. However, other mechanisms can not be discarded. Large sample analysis can provide clarification. We aim to characterize the light curves of a sample of 107 SLSNe II to provide valuable information that can be used to validate theoretical models. We analyze the gri light curves of SLSNe II obtained through ZTF. We study peak absolute magnitudes and characteristic timescales. When possible we compute g-r colors, pseudo-bolometric light curves, and estimate lower limits for their total radiated energy. We also study the luminosity distribution of our sample and estimate the percentage of them that would be observable by the LSST. Finally, we compare our sample to other H-rich SNe and to H-poor SLSNe I. SLSNe II are heterogeneous. Their median peak absolute magnitude is -20.3 mag in optical bands. Their rise can take from two weeks to over three months, and their decline from twenty days to over a year. We found no significant correlations between peak magnitude and timescales. SLSNe II tend to show fainter peaks, longer declines and redder colors than SLSNe I. We present the largest sample of SLSNe II light curves to date, comprising of 107 events. Their diversity could be explained by considering different CSM morphologies. Although, theoretical analysis is needed to explore alternative scenarios. Other luminous transients, such as Active Galactic Nuclei, Tidal Disruption Events or SNe Ia-CSM, can easily become contaminants. Thus, good multi-wavelength light curve coverage becomes paramount. LSST could miss 30 percent of the ZTF events in the its footprint in gri bands. Redder bands become important to construct complete samples.

PG 1448+273 is a luminous, nearby ($z=0.0645$), narrow line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultra fast outflow, as seen through its blueshifted iron K absorption profile, where the outflow velocity appeared to vary in the range $0.1-0.3c$. In this work, new X-ray observations of PG 1448 are presented, in the form of four simultaneous XMM-Newton and NuSTAR observations performed in July and August 2023. The X-ray spectra appeared at a similar flux in each observation, making it possible to analyze the mean 2023 X-ray spectrum at high signal to noise. A broad ($\sigma=1$ keV) and highly blue-shifted ($E=9.8\pm0.4$ keV) iron K absorption profile is revealed in the mean spectrum. The profile can be modeled by a fast, geometrically thick accretion disk wind, which reveals a maximum terminal velocity of $v_{\infty}=-0.43\pm0.03c$, one of the fastest known winds in a nearby AGN. As a result, the inferred mass outflow rate of the wind may reach a significant fraction of the Eddington accretion rate.

A primary science goal for JWST is to detect and characterize the atmospheres of terrestrial planets orbiting M dwarfs (M-Earths). The existence of atmospheres on M-Earths is highly uncertain because their host stars' extended history of high XUV irradiation may act to completely remove their atmospheres. We present two JWST secondary eclipse observations of the M-Earth Gl 486b (also known as GJ 486b) between 5-12 $\mu$m. We combined these observations with a precise analysis of the host star parameters to derive a planetary dayside temperature of $T_{p}=865 \pm 14$ K. We compared this temperature to the maximum expected temperature for a zero albedo, zero heat redistribution bare rock and derived a temperature ratio of $R=\frac{T_{p,dayside}}{T_{p,max}}=0.97 \pm 0.01$. This value is consistent with an airless body with a slight non-zero albedo or a thin atmosphere with $<1$% H$_{2}$O or $<1$ ppm CO$_{2}$. However, it is inconsistent with an Earth- or Venus-like atmosphere, and the spectrum shows no clear emission or absorption features. Additionally, our observations are inconsistent with the water-rich atmospheric scenario allowed by previous transit observations and suggest the transmission spectrum was instead shaped by stellar contamination (Moran et al. 2023). Given the potential for atmospheric escape throughout the system's $\geq6.6$-Gyr lifetime (Diamond-Lowe et al. 2024), we conclude that the observations are likely best explained by an airless planet. This result is the most precise measurement yet of terrestrial exoplanet thermal emission with JWST, which places a strong constraint on the position of the "Cosmic Shoreline" between airless bodies and those with atmospheres.

The population of short-period giant exoplanets around M-dwarf stars is slowly rising. These planets present an extraordinary opportunity for atmospheric characterisation and defy our current understanding of planetary formation. Furthermore, clouds and hazes are ubiquitous in warm exoplanets but their behaviour is still poorly understood. We study the case of a standard warm Jupiter around a M-dwarf star to show the opportunity of this exoplanet population for atmospheric characterisation. We aim to derive the cloud, haze, and chemical budget of such planets using JWST. We leverage a 3D Global Climate Model, the generic PCM, to simulate the cloudy and cloud-free atmosphere of warm Jupiters around a M-dwarf. We then post-process our simulations to produce spectral phase curves and transit spectra as would be seen with JWST.We show that using the amplitude and offset of the spectral phase curves, we can directly infer the presence of clouds and hazes in the atmosphere of such giant planets. Chemical characterisation of multiple species is possible with an unprecedented signal-to-noise ratio, using the transit spectrum in one single visit. In such atmospheres, NH3 could be detected for the first time in a giant exoplanet. We make the case that these planets are key to understanding the cloud and haze budget in warm giants. Finally, such planets are targets of great interest for Ariel.

We report the timing and spectral studies of the accreting X-ray pulsar 4U 2206+54 using astrosat and hxmt observations taken in 2016 and 2020 respectively. X-ray pulsations from the system are detected by both missions. The astrosat discovered a significant periodic signal at $\sim 5619$ s in 2016 and hxmt found a pulsation period at $\sim 5291$ s in 2020. A comparison of its spin-period evolution with the present spin-period estimates shows that the neutron star in 4U 2206+54 now has recently undergoing a spin-up episode after attaining to its slow pulsations of ~5750~s around 2015 from its prolonged spin-down phase. The present average spin-up rate of the pulsar is found to be at $\sim1.2\times10^{-13}$ Hz~s$^{-1}$. The phase-averaged spectra of the pulsar in 1-60\kev could be explained with a high energy cutoff power-law continuum model, no evident line features are found with astrosat. The application of Comptonization models such as comptt and compmag to the phase averaged spectra of 4U 2206+54 reveal a hotter source photon region near the pulsar with an emission size extending to $\sim 2-2.8$~km. Using the quasi-spherical settling accretion theory, we explain the present spin-up and the possibility of strong magnetic field of the pulsar.

The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind. However, because our view of the Sun is limited in the ecliptic plane, the polar regions remain largely uncharted. Using the high spatial resolution and polarimetric precision vector magnetograms observed by Hinode from 2012 to 2021, we investigate the long-term variation of the magnetic fields in polar caps at different latitudes. The Hinode magnetic measurements show that the polarity reversal processes in the north and south polar caps are non-simultaneous. The variation of the averaged radial magnetic flux density reveals that, in each polar cap, the polarity reversal is completed successively from the 70 degree latitude to the pole, reflecting a poleward magnetic flux migration therein. These results clarify the polar magnetic polarity reversal process at different latitudes.

With ongoing advancements in nuclear theory and experimentation, together with a growing body of neutron star (NS) observations, a wealth of information on the equation of state (EOS) for matter at extreme densities has become accessible. Here, we utilize a hybrid EOS formulation that combines an empirical parameterization centered around the nuclear saturation density with a generic three-segment piecewise polytrope model at higher densities. We incorporate data derived from chiral effective field theory ($\chi$EFT), perturbative quantum chromodynamics (pQCD), and from experiments such as PREX-II and CREX. Furthermore, we examine the influence of a total of 129 NS mass measurements up to April 2023, as well as simultaneous mass and radius measurements derived from the X-ray emission from surface hot spots on NSs. Additionally, we consider constraints on tidal properties inferred from the gravitational waves emitted by coalescing NS binaries. To integrate this extensive and varied array of constraints, we utilize a hierarchical Bayesian statistical framework to simultaneously deduce the EOS and the distribution of NS masses. We find that incorporating data from $\chi$EFT significantly tightens the constraints on the EOS of NSs near or below the nuclear saturation density. However, constraints derived from pQCD computations and nuclear experiments such as PREX-II and CREX have minimal impact.

Recent JWST observations of very early galaxies, at $z \geq 10$, has led to claims that tension exists between the sizes and luminosities of high-redshift galaxies and what is predicted by standard ${\Lambda}$CMD models. Here we use the adaptive mesh refinement code Enzo and the N-body smoothed particle hydrodyanmics code SWIFT to compare (semi-)analytic halo mass functions against the results of direct N-body models at high redshift. In particular, our goal is to investigate the variance between standard halo mass functions derived from (semi-)analytic formulations and N-body calculations and to determine what role any discrepancy may play in driving tensions between observations and theory. We find that the difference between direct N-body calculations and halo mass function fits is less than a factor of two within the mass range of galaxies currently being observed by JWST and is therefore not a dominant source of error when comparing theory and observation at high redshift.

We present deep, wideband multifrequency radio observations (144 MHz$-$8 GHz) of the remarkable galaxy group NGC 741, which yield crucial insights into the interaction between the infalling head-tail radio galaxy (NGC 742) and the main group. Our new data provide an unprecedentedly detailed view of the NGC 741-742 system, including the shock cone, disrupted jets from NGC 742, the long ($\sim$ 255 kpc) braided southern radio tail, and eastern lobe-like structure, and reveal, for the first time, complex radio filaments throughout the tail and lobe, and a likely vortex ring behind the shock cone. The cone traces the bow shock caused by the supersonic ($\mathcal{M}\sim2$) interaction between the head-tail radio galaxy NGC 742 and the intragroup medium (IGrM) while the ring may have been formed by interaction between the NGC 742 shock and a previously existing lobe associated with NGC 741. This interaction plausibly compressed and re-accelerated the radio plasma. We estimate that shock-heating by NGC 742 has likely injected $\sim$2-5$\times$10$^{57}$ erg of thermal energy into the central 10 kpc cooling region of the IGrM, potentially affecting the cooling and feedback cycle of NGC 741. A comparison with Chandra X-ray images shows that some of the previously detected thermal filaments align with radio edges, suggesting compression of the IGrM as the relativistic plasma of the NGC 742 tail interacts with the surrounding medium. Our results highlight that multi-frequency observations are key to disentangling the complex, intertwined origins of the variety of radio features seen in the galaxy group NGC 741, and the need for simulations to reproduce all the detected features.

The stellar-mass--halo-mass (SMHM) relation is central to our understanding of galaxy formation and the nature of dark matter. However, its normalisation, slope, and scatter are highly uncertain at dwarf galaxy scales. In this paper, we present DarkLight, a new semi-empirical dwarf galaxy formation model designed to robustly predict the SMHM relation for the smallest galaxies. DarkLight harnesses a correlation between the mean star formation rate of dwarfs and their peak rotation speed -- the $\langle$SFR$\rangle$-$v_{\rm max}$ relation -- that we derive from simulations and observations. Given the sparsity of data for isolated dwarfs with $v_{\rm max} \lesssim 20$ km/s, we fit the $\langle$SFR$\rangle$-$v_{\rm max}$ relation to observational data for dwarfs above this velocity scale and to the high-resolution EDGE cosmological simulations below. Reionisation quenching is implemented via distinct $\langle$SFR$\rangle$-$v_{\rm max}$ relations before and after reionisation. We find that the SMHM scatter is small at reionisation, $\sim$0.2 dex, but rises to $\sim$0.5 dex ($1\sigma$) at a halo mass of $\sim$10$^9$ M$_\odot$ as star formation is quenched by reionisation but dark matter halo masses continue to grow. While we do not find a significant break in the slope of the SMHM relation, one can be introduced if reionisation occurs early ($z_{\rm quench} \gtrsim 5$). Finally, we find that dwarfs can be star forming today down to a halo mass of $\sim$2 $\times 10^9$ M$_\odot$. We predict that the lowest mass star forming dwarf irregulars in the nearby universe are the tip of the iceberg of a much larger population of quiescent isolated dwarfs.

In this work, we investigate the impact of the possibility of a small, subsolar mass compact star, such as the recently reported central compact object of HESS J1731-347, on the equation of state (EOS) of neutron stars. We have used a hybrid approach to the nuclear EOS developed recently where the matter around nuclear saturation density is described by a parametric expansion in terms of nuclear empirical parameters and represented in an agnostic way at higher density using piecewise polytropes. We have incorporated the inputs provided by the latest neutron skin measurement experiments from PREX-II and CREX, simultaneous mass-radius measurements of pulsars PSR J0030+0451 and PSR J0740+6620, and the gravitational wave events GW170817 and GW190425. The main results of the study show the effect of HESS J1731-347 on the nuclear parameters and neutron star observables. Our analysis yields the slope of symmetry energy $L=45.71^{+38.18}_{-22.11}$ MeV, the radius of a $1.4 M_\odot$ star, $R_{1.4}=12.18^{+0.71}_{-0.88}$ km, and the maximum mass of a static star, $M_{\rm max}= 2.14^{+0.26}_{-0.17} M_\odot$ within $90\%$ confidence interval, respectively.

Satellite constellation interference occurs across astronomical disciplines. We present examples of interference from radio and $\gamma$-Ray astronomy to optical and spectroscopic interference in ground-based and space-borne facilities. In particular, we discuss the impact of artificial satellites on the Hubble Space Telescope (HST), the High Energy Stereoscopic System (H.E.S.S.), an Imaging Atmospheric Cherenkov Telescope, as well as possible mitigation strategies for the European Southern Observatory 4-metre Multi-Object Spectrograph Telescope (ESO 4MOST). Furthermore, we shed light on how ground-based optical telescopes such as the Oukaimeden Observatory contribute to IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS) efforts that quantify satellite brightness.

This Birds-of-a-Feather (BOF) session on 6 November 2023 was organized by leaders and members of SatHub at the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS). SatHub is dedicated to observations, data analysis, software, and related activities. The session opened with a talk on the current state of affairs with regards to satellite constellation mitigation, with a focus on optical astronomy, and moved to focused discussion around the top-voted topics. These included tools and techniques for forecasting satellite positions and brightnesses as well as streak detection and masking.

Forbidden collisionally excited optical atomic transitions from high ionization potential (IP$\geq$54.8\,eV) ions, such as Ca$^{\mathrm{4+}}$, Ne$^{\mathrm{4+}}$, Fe$^{\mathrm{6+}}$, Fe$^{\mathrm{10+}}$, Fe$^{\mathrm{13+}}$, Ar$^{\mathrm{9+}}$, and S$^{\mathrm{11+}}$, are known as optical coronal lines (CLs). The spectral energy distribution (SED) of active galactic nuclei (AGN) typically extends to hundreds of electron volts and above, which should be able to produce such highly ionized gas. However, optical CLs are often not detected in AGN. Here we use photoionization calculations with the \textsc{Cloudy} spectral synthesis code to determine possible reasons for the rarity of these optical CLs. We calculate CL luminosities and equivalent widths from radiation pressure confined photoionized gas slabs exposed to an AGN continuum. We consider the role of dust, metallicity, and ionizing SED in the formation of optical CLs. We find that (1) dust reduces the strength of most CLs by $\sim$three orders of magnitude, primarily as a result of depletion of metals onto the dust grains. (2) In contrast to the CLs, the more widely observed lower IP optical lines such as [O\, III] 5007\,Å, are less affected by depletion and some are actually enhanced in dusty gas. (3) In dustless gas many optical CLs become detectable, and are particularly strong for a hard ionizing SED. This implies that prominent CL emission likely originate in dustless gas. Our calculations also suggest optical CL emission is enhanced in galaxies with low mass black holes characterized by a harder radiation field and a low dust to metal ratio. The fact that optical CLs are not widely observed in the early universe with JWST may point to rapid dust formation at high redshift.

Due to the unprecedented depth of the upcoming ground-based Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory, approximately two-thirds of the galaxies are likely to be affected by blending - the overlap of physically separated galaxies in images. Thus, extracting reliable shapes and photometry from individual objects will be limited by our ability to correct blending and control any residual systematic effect. Deblending algorithms tackle this issue by reconstructing the isolated components from a blended scene, but the most commonly used algorithms often fail to model complex realistic galaxy morphologies. As part of an effort to address this major challenge, we present MADNESS, which takes a data-driven approach and combines pixel-level multi-band information to learn complex priors for obtaining the maximum a posteriori solution of deblending. MADNESS is based on deep neural network architectures such as variational auto-encoders and normalizing flows. The variational auto-encoder reduces the high-dimensional pixel space into a lower-dimensional space, while the normalizing flow models a data-driven prior in this latent space. Using a simulated test dataset with galaxy models for a 10-year LSST survey and a galaxy density ranging from 48 to 80 galaxies per arcmin2 we characterize the aperture-photometry g-r color, structural similarity index, and pixel cosine similarity of the galaxies reconstructed by MADNESS. We compare our results against state-of-the-art deblenders including scarlet. With the r-band of LSST as an example, we show that MADNESS performs better than in all the metrics. For instance, the average absolute value of relative flux residual in the r-band for MADNESS is approximately 29% lower than that of scarlet. The code is publicly available on GitHub.

Photometric wide-field surveys are imaging the sky in unprecedented detail. These surveys face a significant challenge in efficiently estimating galactic photometric redshifts while accurately quantifying associated uncertainties. In this work, we address this challenge by exploring the estimation of Probability Density Functions (PDFs) for the photometric redshifts of galaxies across a vast area of 17,000 square degrees, encompassing objects with a median 5$\sigma$ point-source depth of $g$ = 24.3, $r$ = 23.9, $i$ = 23.5, and $z$ = 22.8 mag. Our approach uses deep learning, specifically integrating a Recurrent Neural Network architecture with a Mixture Density Network, to leverage magnitudes and colors as input features for constructing photometric redshift PDFs across the whole DECam Local Volume Exploration (DELVE) survey sky footprint. Subsequently, we rigorously evaluate the reliability and robustness of our estimation methodology, gauging its performance against other well-established machine learning methods to ensure the quality of our redshift estimations. Our best results constrain photometric redshifts with the bias of $-0.0013$, a scatter of $0.0293$, and an outlier fraction of $5.1\%$. These point estimates are accompanied by well-calibrated PDFs evaluated using diagnostic tools such as Probability Integral Transform and Odds distribution. We also address the problem of the accessibility of PDFs in terms of disk space storage and the time demand required to generate their corresponding parameters. We present a novel Autoencoder model that reduces the size of PDF parameter arrays to one-sixth of their original length, significantly decreasing the time required for PDF generation to one-eighth of the time needed when generating PDFs directly from the magnitudes.