Papers for Wednesday, Dec 07 2022

Masses and radii of stars can be derived by combining eclipsing binary light curves with spectroscopic orbits. In our previous work, we modeled the All-Sky Automated Survey for Supernovae (ASAS-SN) light curves of more than 30,000 detached eclipsing binaries using PHOEBE. Here we combine our results with 128 double-lined spectroscopic orbits from Gaia Data Release 3. We visually inspect ASAS-SN light curves of double-lined spectroscopic binaries on the lower main sequence and the giant branch, adding 11 binaries to our sample. We find that only 50% of systems have Gaia periods and eccentricities consistent with the ASAS-SN values. We use emcee and PHOEBE to determine masses and radii for a total of 122 stars with median fractional uncertainties of 7.9% and 6.3%, respectively.

We investigate the formation channels of the intracluster light (ICL) and the brightest cluster galaxy (BCG) in clusters at $z=0$. For this, we perform multi-resolution cosmological N-body simulations using the "Galaxy Replacement Technique" (GRT). We study the formation channels of the ICL and BCG as a function of distance from the cluster center and the dynamical state of the clusters at $z=0$. To do this, we trace back the stars of the ICL and BCG, and identify the stellar components in which they existed when they first fell into the clusters. We find that the progenitors of the ICL and BCG in the central region of the cluster fell earlier and with a higher total mass ratio of the progenitors to the cluster compared to the outer region. This causes a negative radial gradient in the infall time and total mass ratio of the progenitors. Although stellar mass of the progenitors does not show the same radial gradient in all clusters, massive galaxies ($M_{\rm{gal}} > 10^{10}~M_{\odot}~h^{-1}$) are the dominant formation channel of the ICL and BCG for all clusters, except for our most relaxed cluster. For clusters that are dynamically more unrelaxed, we find that the progenitors of the ICL and BCG fall into their clusters more recently, and with a higher mass and mass ratio. Furthermore, we find that the diffuse material of massive galaxies and group-mass halos that is formed by pre-processing contributes significantly to the ICL in the outer region of the unrelaxed clusters.

We present dynamical models of the narrow line region (NLR) outflows in the nearby Seyfert galaxies Mrk 3, Mrk 78, NGC 1068, and NGC 4151 using observations from the Hubble Space Telescope and Apache Point Observatory. We employ long-slit spectroscopy to map the spatially-resolved outflow and rotational velocities of the ionized gas. We also perform surface brightness decompositions of host galaxy images to constrain the enclosed stellar mass distributions as functions of distance from the supermassive black holes (SMBHs). Assuming that the NLR gas is accelerated by AGN radiation pressure, and subsequently decelerated by the host galaxy and SMBH gravitational potentials, we derive outflow velocity profiles where the gas is launched in situ at multiple distances from the SMBH. We find a strong correlation between the turnover (from acceleration to deceleration) radii from our models, with the turnovers seen in the observed velocities and spatially-resolved mass outflow rates for the AGN with bolometric luminosities $>$ 10$^{44}$ erg sec$^{-1}$. This consistency indicates that radiation pressure is the dominant driving mechanism behind the NLR outflows in these moderate-luminosity AGN, with a force multiplier $\sim$500 yielding the best agreement between the modeled and observed turnover radii. However, in Meena2021 we found that this trend may not hold at lower luminosities, where our modeled turnover distance for NGC 4051 is much smaller than in the observed kinematics. This result may indicate that either additional force(s) are responsible for accelerating the NLR outflows in low-luminosity AGN, or higher spatial resolution observations are required to quantify their turnover radii.

WR 20a is the most massive close-in binary known in our Galaxy. It is composed of two $\approx$80 M$_\odot$ Wolf-Rayet stars with a short period of $\approx$3.7 days in the open cluster Westerlund 2. As such, WR 20a presents us with a unique laboratory for studying the currently uncertain physics of binary evolution and compact object formation as well as for studying the wind collision region in an massive eclipsing binary system. We use deep Chandra observations of WR 20a to study the time variability of the wind collision region between the two Wolf-Rayet stars and are able to produce an X-ray light curve covering $\approx$2/3 of its orbital period. We find that the X-ray light curve is asymmetric because the flux of one peak is 2.5$\sigma$ larger than the flux of the other peak. This asymmetry could be caused by asymmetric mass-loss from the two stars or by the lopsidedness of the wind collision region due to the unusually fast rotation of the system. The X-ray light curve is also shifted in phase space when compared to the optical light curves measured by TESS and ASAS-SN. Additionally, we explore the ultimate fate of this system by modeling the resultant binary black hole merger expected at the end of the two stars' lives. We conclude that this system will evolve to be a representative of the sub-population of LIGO progenitors of fast-spinning binary black hole merger events.

Recent attempts to detect [OIII] 88$\mu$m emission from super-early ($z>10$) galaxy candidates observed by JWST have been unsuccessful. By using zoom-in simulations, we show that these galaxies are faint, and mostly fall below the local metal-poor $\rm [OIII]-SFR$ relation as a result of their low ionization parameter, $U_{\rm ion}\lesssim 10^{-3}$. Such low $U_{\rm ion}$ values are found in galaxies that are in an early assembly stage, and whose stars are still embedded in high-density natal clouds. However, the most luminous galaxy in our sample ($\rm{log}[L_{\rm{[OIII]}}/L_\odot] = 8.4$, $U_{\rm ion} \approx 0.1$) could be detected by ALMA in only $2.8$ hrs.

We compute synthetic, rest-frame optical and ultraviolet (UV) emission-line properties of galaxy populations at redshifts from z$\approx$0 to z=8 in a full cosmological framework. We achieve this by coupling, in post-processing, the cosmological IllustrisTNG simulations with new-generation nebular-emission models, accounting for line emission from young stars, post-asymptotic-giant-branch (PAGB) stars, accreting black holes (BHs) and, for the first time, fast radiative shocks. The optical emission-line properties of simulated galaxies dominated by different ionizing sources are largely consistent with those expected from classical diagnostic diagrams and reflect the observed increase in [OIII]/H$\beta$ at fixed [NII]/H$\alpha$ and the evolution of the H$\alpha$, [OIII]$\lambda5007$ and [OII]$\lambda3727$ luminosity functions from z$\approx$0 to z$\sim$2. At higher redshift, we find that the emission-line galaxy population is dominated by star-forming and active galaxies, with negligible fractions of shock- and PAGB-dominated galaxies. We highlight 10 UV-diagnostic diagrams able to robustly identify the dominant ionizing sources in high-redshift galaxies. We also compute the evolution of several optical- and UV-line luminosity functions from z=4 to z=7, and the number of galaxies expected to be detectable per field of view in deep, medium-resolution spectroscopic observations with the NIRSpec instrument on board the James Webb Space Telescope. We find that 2-hour-long exposures are sufficient to achieve unbiased censuses of H$\alpha$ and [OIII]$\lambda5007$ emitters, while at least 5 hours are required for H$\beta$, and even 10 hours will detect only progressively smaller fractions of [OII]$\lambda3727$, OIII]$\lambda1663$, CIII]$\lambda1908$, CIV$\lambda1550$, [NII]$\lambda6584$, SiIII]$\lambda1888$ and HeII$\lambda1640$ emitters, especially in the presence of dust.

Self-gravity plays an important role in the evolution of rotationally supported systems such as protoplanetary disks, accretion disks around black holes, or galactic disks, as it can both feed turbulence or lead to gravitational fragmentation. While such systems can be studied in the shearing box approximation with high local resolution, the large density contrasts that are possible in the case of fragmentation still limit the utility of Eulerian codes with constant spatial resolution. In this paper, we present a novel self-gravity solver for the shearing box based on the TreePM method of the moving-mesh code AREPO. The spatial gravitational resolution is adaptive which is important to make full use of the quasi-Lagrangian hydrodynamical resolution of the code. We apply our new implementation to two- and three-dimensional, self-gravitating disks combined with a simple $\beta$-cooling prescription. For weak cooling we find a steady, gravoturbulent state, while for strong cooling the formation of fragments is inevitable. To reach convergence for the critical cooling efficiency above which fragmentation occurs, we require a smoothing of the gravitational force in the two dimensional case that mimics the stratification of the three-dimensional simulations. The critical cooling efficiency we find, $\beta \approx 3$, as well as box-averaged quantities characterizing the gravoturbulent state, agree well with various previous results in the literature. Interestingly, we observe stochastic fragmentation for $\beta > 3$, which slightly decreases the cooling efficiency required to observe fragmentation over the lifetime of a protoplanetary disk. The numerical method outlined here appears well suited to study the problem of galactic disks as well as magnetized, self-gravitating disks.

Emission lines with a double-peak (DP) shape, detected in the centre of galaxies, have been extensively used in the past to identify peculiar kinematics such as dual active galactic nuclei, outflows or mergers. From a large DP galaxy sample, a connection to minor merger galaxies with ongoing star formation was suggested. To gain a better understanding of different mechanisms creating a DP signature, we here explore synthetic SDSS spectroscopic observations computed from disc models and simulations. We show how a DP signature is connected to the central part of the rotation curve of galaxies, which is mostly shaped by the stellar bulge. We, furthermore, find that bars can create strong DP emission-line signatures when viewed along their major axis. Major mergers can form a central rotating disc in late post-coalescence merger stages (1\,Gyr after the final coalescence), which creates a DP signature. Minor mergers tend to show a DP feature with no correlation to the galaxy inclination within 350\,Myr after the final coalescence. Comparisons of these scenarii with observations disfavour major mergers, since these show predominantly elliptical and only a few S0 morphologies. Furthermore, at such a late merger stage the enhanced star formation is most likely faded. Bars and minor mergers, on the other hand, can be compared quite well with the observations. Both observations coincide with increased star formation found in observations, and minor mergers in particular do not show any dependency with the observation direction. However, observations resolving the galaxy kinematics spatially are needed to distinguish between the discussed possibilities. More insight into the origin of DP will be gained by a broader comparison with cosmological simulations. The understanding of the DP origin can provide important tools to study the mass growth of galaxies in future high redshift surveys.

In the era of huge astronomical surveys, machine learning offers promising solutions for the efficient estimation of galaxy properties. The traditional, `supervised' paradigm for the application of machine learning involves training a model on labelled data, and using this model to predict the labels of previously unlabelled data. The semi-supervised `pseudo-labelling' technique offers an alternative paradigm, allowing the model training algorithm to learn from both labelled data and as-yet unlabelled data. We test the pseudo-labelling method on the problems of estimating redshift, stellar mass, and star formation rate, using COSMOS2015 broad band photometry and one of several publicly available machine learning algorithms, and we obtain significant improvements compared to purely supervised learning. We find that the gradient-boosting tree methods CatBoost, XGBoost, and LightGBM benefit the most, with reductions of up to ~15% in metrics of absolute error. We also find similar improvements in the photometric redshift catastrophic outlier fraction. We argue that the pseudo-labellng technique will be useful for the estimation of redshift and physical properties of galaxies in upcoming large imaging surveys such as Euclid and LSST, which will provide photometric data for billions of sources.

Source finding is one of the most challenging tasks in upcoming radio continuum surveys with SKA precursors, such as the Evolutionary Map of the Universe (EMU) survey of the Australian SKA Pathfinder (ASKAP) telescope. The resolution, sensitivity, and sky coverage of such surveys is unprecedented, requiring new features and improvements to be made in existing source finders. Among them, reducing the false detection rate, particularly in the Galactic plane, and the ability to associate multiple disjoint islands into physical objects. To bridge this gap, we developed a new source finder, based on the Mask R-CNN object detection framework, capable of both detecting and classifying compact, extended, spurious, and poorly imaged sources in radio continuum images. The model was trained using ASKAP EMU data, observed during the Early Science and pilot survey phase, and previous radio survey data, taken with the VLA and ATCA telescopes. On the test sample, the final model achieves an overall detection completeness above 85\%, a reliability of $\sim$65\%, and a classification precision/recall above 90\%. Results obtained for all source classes are reported and discussed.

The evolutionary history of an extrasolar system is, in part, fossilized through its planets' orbital orientations relative to the host star's spin axis. However, spin-orbit constraints for warm Jupiters -- particularly in binary star systems, which are amenable to a wide range of dynamical processes -- are relatively scarce. We report a measurement of the Rossiter-McLaughlin effect, observed with the Keck/HIRES spectrograph, across the transit of Qatar-6 A b: a warm Jupiter orbiting one star within a binary system. From this measurement, we obtain a sky-projected spin-orbit angle $\lambda={0.1\pm2.6}^{\circ}$. Combining this new constraint with the stellar rotational velocity of Qatar-6 A that we measure from TESS photometry, we derive a true obliquity $\psi={21.82^{+8.86}_{-18.36}}^{\circ}$ -- consistent with near-exact alignment. We also leverage astrometric data from Gaia DR3 to show that the Qatar-6 binary star system is edge-on ($i_{B}={90.17^{+1.07}_{-1.06}}^{\circ}$), such that the stellar binary and the transiting exoplanet orbit exhibit line-of-sight orbit-orbit alignment. Ultimately, we demonstrate that all current constraints for the 3-body Qatar-6 system are consistent with both spin-orbit and orbit-orbit alignment. High-precision measurements of the projected stellar spin rate of the host star and the sky-plane geometry of the transit relative to the binary plane are required to conclusively verify the full 3D configuration of the system.

Magnetic fields grown by instabilities driven by differential rotation are believed to be essential to accretion onto black holes. These instabilities saturate in a turbulent state; therefore, the spatial and temporal variability in the horizon-resolving images of Sagittarius A* (Sgr A*) will be able to empirically assess this critical aspect of accretion theory. However, interstellar scattering blurs high-frequency radio images from the Galactic center and introduces spurious small-scale structures, complicating the interpretation of spatial fluctuations in the image. We explore the impact of interstellar scattering on the polarized images of Sgr A* and demonstrate that for credible physical parameters, the intervening scattering is non-birefringent. Therefore, we construct a scattering mitigation scheme that exploits horizon-resolving polarized millimeter/submillimeter VLBI observations to generate statistical measures of the intrinsic spatial fluctuations and therefore the underlying accretion flow turbulence. An optimal polarization basis is identified, corresponding to measurements of the fluctuations in magnetic field orientation in three dimensions. We validate our mitigation scheme using simulated data sets and find that current and future ground-based experiments will readily be able to accurately measure the image-fluctuation power spectrum.

The mass ratio $q$ of a contact binary star evolves due to mass transfer, magnetic braking, and thermal relaxation oscillations to small values until it crosses a critical threshold $q_\text{min}$. When that happens, the binary undergoes the tidal Darwin instability, leading to a rapid coalescence of the components and observable brightening of the system. So far, the distribution of $q$ has not been measured on a sufficiently large population of contact binary stars, because the determination of $q$ for a single contact binary usually requires spectroscopy. But as was shown previously, it is possible to infer the mass-ratio distribution of the entire population of contact binaries from the observed distribution of their light curve amplitudes. Employing Bayesian inference, we obtain a sample of contact binary candidates from the Kepler Eclipsing Binary Catalog combined with data from Gaia and estimates of effective temperatures. We assign to each candidate a probability of being a contact binary of either late or early type. Overall, our sample includes about 300 late-type and 200 early-type contact binary candidates. We model the amplitude distribution assuming that mass ratios are described by a power law with an exponent $b$ and a cut off at $q_\text{min}$. We find $q_\text{min}=0.087^{+0.024}_{-0.015}$ for late-type contact binaries with periods longer than 0.3 days. For late-type binaries with shorter periods, we find $q_\text{min}=0.246^{+0.029}_{-0.046}$, but the sample is small. For early type contact binary stars with periods shorter than 1 day, we obtain $q_\text{min}=0.030^{+0.018}_{-0.022}$. These results indicate a dependence of $q_\text{min}$ on the structure of the components and are broadly compatible with previous theoretical predictions. Our method can be easily extended to large samples of contact binaries from TESS and other space-based surveys.

We compare void size and clustering statistics for nDGP and $f(R)$ gravity models and GR using N-body simulations. We show how it is critical to consider the statistics derived from mock galaxy catalogs rather than the dark matter halos alone. Marked differences between the void size functions for GR and $f(R)$ models which present when voids are identified using dark matter halos are removed when voids are identified, more realistically, from mock galaxy tracers of the halos. The void radial velocities and velocity dispersions in the $f(R)$ and nDGP models are enhanced relative to GR in both halos and mock galaxy identified voids. Despite this, we find that the redshift space void quadrupole moments derived from the mock galaxy tracers are strikingly similar across the three gravity models. The Gaussian Streaming Model (GSM) is shown to accurately reconstruct $\xi_2$ in modified gravity models and we employ the GSM, using a functional derivative approach, to analyze the insensitivity of $\xi_2$ to the gravity model. Assuming linear theory, we show the void quadrupole to be an unbiased estimator of the redshift space growth rate parameter $\beta=f/b$ in the modified gravity theories.

Since February of this year, KOA began to prepare, transfer, and ingest data as they were acquired in near-real time; in most cases data are available to observers through KOA within one minute of acquisition. Real-time ingestion will be complete for all active instruments by the end of Summer 2022. The observatory is supporting the development of modern Python data reduction pipelines, which when delivered, will automatically create science-ready data sets at the end of each night for ingestion into the archive. This presentation will describe the infrastructure developed to support real-time data ingestion, itself part of a larger initiative at the Observatory to modernize end-to-end operations. During telescope operations, the software at WMKO is executed automatically when a newly acquired file is recognized through monitoring a keyword-based observatory control system; this system is used at Keck to execute virtually all observatory functions. The monitor uses callbacks built into the control system to begin data preparation of files for transmission to the archive on an individual basis: scheduling scripts or file system related triggers are unnecessary. An HTTP-based system called from the Flask micro-framework enables file transfers between WMKO and NExScI and triggers data ingestion at NExScI. The ingestion system at NEXScI is a compact (4 KLOC), highly fault-tolerant, Python-based system. It uses a shared file system to transfer data from WMKO to NExScI. The ingestion code is instrument agnostic, with instrument parameters read from configuration files. It replaces an unwieldy (50 KLOC) C-based system that had been in use since 2004.

The Third Catalog of Hard Fermi Large Area Telescope Sources (3FHL) reports the detection of 1556 objects at E > 10 GeV. However, 177 sources remain unassociated and 23 are associated with a ROSAT X-ray detection of unknown origin. Pointed X-ray observations were conducted on 30 of these unassociated and unknown sources with Swift-XRT. A bright X-ray source counterpart was detected in 21 out of 30 fields. In five of these 21 fields, we detected more than one X-ray counterpart, totaling 26 X-ray sources analyzed. Multiwavelength data was compiled for each X-ray source detected. We find that 21 out of the 26 X-ray sources detected display the multiwavelength properties of blazars, while one X-ray source displays the characteristics of a Galactic source. Using trained decision tree, random forest, and support vector machine models, we predict all 21 blazar counterpart candidates to be BL Lacertae objects (BL Lacs). This is in agreement with BL Lacs being the most populous source class in the 3FHL.

The North Celestial Pole Loop (NCPL) provides a unique laboratory for studying the early stage precursors of star formation. Uncovering its origin is key to understanding the dynamical mechanisms that control the evolution of its contents. In this study, we explore the 3D geometry and the dynamics of the NCPL using high-resolution dust extinction data and H I data, respectively. We find that material toward Polaris and Ursa Major is distributed along a plane similarly oriented to the Radcliffe wave. The Spider projected in between appears disconnected in 3D, a discontinuity in the loop shape. We find that the elongated cavity that forms the inner part of the NCPL is a protrusion of the Local Bubble (LB) likely filled with warm (possibly hot) gas that passes through and goes beyond the location of the dense clouds. An idealized model of the cavity as a prolate spheroid oriented toward the observer, reminiscent of the cylindrical model proposed by Meyerdierks et al. (1991), encompasses the protrusion and fits into arcs of warm H I gas expanding laterally to it. As first argued by Meyerdierks et al. (1991), the non-spherical geometry of the cavity and the lack of OB stars interior to it disfavor an origin caused by a single point-like source of energy or multiple supernovae. Rather, the formation of the protrusion could be related to the propagation of warm gas from the LB into a pre-existing non-uniform medium in the lower halo, the topology of which was likely shaped by past star formation activity along the Local Arm.

We describe a method for regularizing, post-facto, the point-spread function of a telescope or other imaging instrument, across its entire field of view. Imaging instruments in general blur point sources of light by local convolution with a point-spread function that varies slowly across the field of view, due to coma, spherical aberration, and similar effects. It is possible to regularize the PSF in post-processing, producing data with a uniform and narrow ``effective PSF'' across the entire field of view. In turn, the method enables seamless wide-field astronomical mosaics at higher resolution than would otherwise be achievable, and potentially changes the design trade space for telescopes, lenses, and other optical systems where data uniformity is important. The method does not require access to the instrument that required the data, and can be bootstrapped from existing data sets that include starfield images.

ZZ Boo is an F-type detached eclipsing binary system containing two almost-identical stars on a circular orbit with a period of 4.992 d. We analyse light curves from two sectors of observations with the Transiting Exoplanet Survey Satellite (TESS) and two published sets of radial velocities of the component stars to determine their physical properties to high precision. We find masses of 1.558 +/- 0.008 Msun and 1.599 +/- 0.012 Msun, and radii of 2.063 +/- 0.006 Rsun and 2.205 +/- 0.006 Rsun. The similarity in the primary and secondary eclipse depths has led to confusion in the past. The high quality of the TESS data means we can, for the first time, clearly identify which is which. The primary star is conclusively hotter but smaller and less massive than the secondary star. We define a new high-precision orbital ephemeris and obtain effective temperatures using the Gaia parallax of the system. The secondary star is more evolved than the primary and a good agreement with theoretical predictions is found for a solar chemical composition and an age of 1.7 Gyr.

The detection and characterization of Earth-like exoplanets around Sun-like stars for future flagship missions requires coronagraphs to achieve contrasts on the order of 1e-10 at close angular separations and over large spectral bandwidths (>=20%). We present our progress thus far on exploring the potential for scalar vortex coronagraphs (SVCs) in direct exoplanet imaging. SVCs are an attractive alternative to vector vortex coronagraphs (VVCs), which have recently demonstrated 6e-9 raw contrast in 20% broadband light but are polarization dependent. SVCs imprint the same phase ramp on the incoming light and do not require polarization splitting, but are inherently limited by their chromatic behavior. Several SVC designs have been proposed in recent years to solve this issue by modulating or wrapping the azimuthal phase function according to specific patterns. For one such design, the staircase SVC, we present our best experimental SVC results demonstrating raw contrast of 2e-7 in 10% broadband light. Since SVC broadband performance and aberration sensitivities are highly dependent on topology, we conducted a comparative study of several SVC designs to optimize for high contrast across a range of bandwidths. Furthermore, we present a new coronagraph optimization tool to predict performance in order to find an achromatic solution.

We present the Cosmic Sands suite of cosmological zoom-in simulations based on the Simba galaxy formation model in order to study the build up of the first massive and dusty galaxies in the early Universe. Residing in the most massive halos, we find that the compact proto-massive galaxies undergo nearly continuous mergers with smaller subhalos, boosting star formation rates (SFRs) and the build up of stellar mass. The galaxies are already appreciably chemically evolved by z=10, with modeled dust masses comparable to those inferred from observations in the same epoch. We track gas accretion onto the galaxies to understand how extreme SFRs can be sustained by these early systems. We find that smooth gas accretion can maintain SFRs above 250 M$_{\odot}$ / yr but to achieve SFRs that boost galaxies well above the main sequence, a larger perturbation like a gas-rich major merger is necessary to trigger a starburst episode. Post-processing the Cosmic Sands simulations with dust radiative transfer, we find that while the infrared luminosities of the most dust rich galaxies are comparable to local ULIRGs, they are substantially dimmer than classical z=2 sub-millimeter galaxies. We end with a discussion on the possible reasons for this discrepancy at the highest masses and the future work we intend to carry out to study the chemical enrichment of the earliest dusty galaxies.

The implications of the water vapor runaway greenhouse phenomenon for water-rich subNeptunes are developed. In particular, the nature of the post-runaway equilibration process for planets that have an extremely high water inventory is addressed. Crossing the threshold from sub-runaway to super-runaway conditions leads to a transition from equilibrated states with cold deep liquid oceans and deep interior ice-X phases to states with hot supercritical fluid interiors. There is a corresponding marked inflation of radius for a given mass, similar to the runaway greenhouse radius inflation effect noted earlier for terrestrial planets, but in the present case the inflation involves the entire interior of the planet. The calculation employs the AQUA equation of state database to simplify the internal structure calculation. Some speculations concerning the effect of $\mathrm{H_2}$ admixture, silicate cores and hot vs. cold start evolution trajectories are offered. Observational implications are discussed, though the search for the mass-radius signature of the phenomena considered is limited by degeneracies and by lack of data.

In this paper, we study how gaseous dynamical friction (DF) affects the motion of fly-by stellar-mass black holes (sBHs) embedded in active galactic nucleus (AGN) discs. We perform 3-body integrations of the interaction of two co-planar sBHs in nearby, initially circular orbits around the supermassive black hole (SMBH). We find that DF can facilitate the formation of gravitationally bound near-Keplerian binaries in AGN discs, and we delineate the discrete ranges of impact parameters and AGN disc parameters for which such captures occur. We also report trends in the bound binaries' eccentricity and sense of rotation (prograde or retrograde with respect to the background AGN disc) as a function of the impact parameter of the initial encounter. While based on an approximate description of gaseous friction, our results suggest that binary formation in AGN discs should be common and may produce both prograde and retrograde, as well as both circular and eccentric binaries.

The PHANGS collaboration has been building a reference dataset for the multi-scale, multi-phase study of star formation and the interstellar medium in nearby galaxies. With the successful launch and commissioning of JWST, we can now obtain high-resolution infrared imaging to probe the youngest stellar populations and dust emission on the scales of star clusters and molecular clouds ($\sim$5-50 pc). In Cycle 1, PHANGS is conducting an 8-band imaging survey from 2-21$\mu$m of 19 nearby spiral galaxies. CO(2-1) mapping, optical integral field spectroscopy, and UV-optical imaging for all 19 galaxies have been obtained through large programs with ALMA, VLT/MUSE, and Hubble. PHANGS-JWST enables a full inventory of star formation, accurate measurement of the mass and age of star clusters, identification of the youngest embedded stellar populations, and characterization of the physical state of small dust grains. When combined with Hubble catalogs of $\sim$10,000 star clusters, MUSE spectroscopic mapping of $\sim$20,000 HII regions, and $\sim$12,000 ALMA-identified molecular clouds, it becomes possible to measure the timescales and efficiencies of the earliest phases of star formation and feedback, build an empirical model of the dependence of small dust grain properties on local ISM conditions, and test our understanding of how dust-reprocessed starlight traces star formation activity, all across a diversity of galactic environments. Here we describe the PHANGS-JWST Treasury survey, present the remarkable imaging obtained in the first few months of science operations, and provide context for the initial results presented in the first series of PHANGS-JWST publications.

We present a comparative study of active galactic nuclei (AGN) between galaxy pairs and isolated galaxies with the final data release of the MaNGA integral field spectroscopic survey. We build a sample of 391 kinematic galaxy pairs within the footprint of the survey and select AGN using the survey's spectra. We use the comoving volume densities of the AGN samples to quantify the effects that tidal interactions have on the triggering of nuclear accretion. Our hypothesis is that the pair sample contains AGN that are triggered by not only stochastic accretion but also tidally induced accretion and correlated accretion. With the level of stochastically triggered AGN fixed by the control sample, we model the strength of tidally induced accretion and correlated accretion as a function of projected separation (rp) and compare the model expectations with the observed volume densities of dual AGN and offset AGN (single AGN in a pair). At rp ~ 10 kpc, we find that tidal interactions induce ~30% more AGN than stochastic fueling and cause ~12% of the offset AGN to become dual AGN because of correlations. The strength of both these effects decreases with increasing rp. We also find that the OIII luminosities of the AGN in galaxy pairs are consistent with those found in isolated galaxies, likely because stochastically fed AGN dominate even among close pairs. Our results illustrates that while we can detect tidally induced effects statistically, it is challenging to separate tidally induced AGN and stochastically triggered AGN in interacting galaxies.

We studied the soft X-ray data of solar flares and found that the distribution functions of flare fluence are successfully modeled by tapered power law or gamma function distributions whose power exponent is slightly smaller than 2, indicating that the total energy of the flare populations is mostly contributed from a small number of large flares. The largest possible solar flares in 1000 years are predicted to be around X70 in terms of the GOES flare class. We also studied superflares (more energetic than solar flares) from solar-type stars, and found that their power exponent in the fitting of the gamma function distribution is around 1.05, much flatter than solar flares. The distribution function of stellar flare energy extrapolated downward does not connect to the distribution function of solar flare energy.

We provide a catalog of visually classified objects in the MaNGA integral field spectroscopic survey. The MaNGA survey is designed to target a single galaxy with each of its integral field units; however, many of these fields will host ancillary objects. We identify these discrete objects by cleaning up SDSS photometric objects in MaNGA's fields-of-view. We then use the spectra from MaNGA's data cubes to spectrally classify the identified objects. The catalog contains the positions and classifications of 1385 stars, 11,439 galaxies, and 107 broad-line active galactic nucleus (BLAGN) from the 10,130 unique MaNGA fields. We also provide spectroscopically derived parameters for the galaxies including; stellar masses, gas and stellar kinematics, and emission-line fluxes and equivalent widths. This catalog effectively expands the size of the MaNGA catalog by ~50%, increasing the utility of the MaNGA project.

The lack of observed sausage perturbations in solar active region loops is customarily attributed to the relevance of cutoff axial wavenumbers and the consequent absence of trapped modes (called ``evanescent eigenmodes'' here). However, some recent eigenvalue problem studies yield that cutoff wavenumbers may disappear for those equilibria where the external density varies sufficiently slowly, thereby casting doubt on the rarity of candidate sausage perturbations. We examine the responses of straight, transversely structured, coronal slabs to small-amplitude sausage-type perturbations that excite axial fundamentals by solving the pertinent initial value problem with eigensolutions for a closed domain. The density variation in the slab exterior is dictated by some steepness parameter $\mu$, and cutoff wavenumbers are theoretically expected to be present (absent) when $\mu \ge 2$ ($\mu < 2$). However, our numerical results show no qualitative difference in the system evolution when $\mu$ varies, despite the differences in the modal behavior. Only oscillatory eigenmodes are permitted when $\mu \ge 2$. Our discrete eigenspectrum becomes increasingly closely spaced when the domain broadens, and an oscillatory continuum results for a truly open system. Oscillatory eigenmodes remain allowed and dominate the system evolution when $\mu <2$. We show that the irrelevance of cutoff wavenumbers does not mean that all fast waves are evanescent. Rather, it means that an increasing number of evanescent eigenmodes emerge when the domain size increases. We conclude that sausage perturbations remain difficult to detect even for the waveguide formulated here.

"Changing-look active galactic nuclei" (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on timescales of years. However, it is still unclear whether materials in broad-line regions (BLRs) in CLAGNs appear and disappear during the type-transition or remain at the same location while the line production is simply activated or deactivated. Here we present our X-ray-optical monitoring results of a CLAGN, NGC 3516, by Suzaku, Swift, and ground telescopes, with our primary focus on the narrow Fe-K$\alpha$ emission line, which is an effective probe of the BLR materials. We detected significant variations of the narrow Fe-K$\alpha$ line on a timescale of tens of days during the type-2 (faint) phase in 2013-2014, and conducted "narrow Fe-K$\alpha$ reverberation mapping," comparing its flux variation with those of the X-ray continuum from a corona and $B$-band continuum from an accretion disk. We derived, as a result, a time lag of $10.1^{+5.8}_{-5.6}$ days ($1\sigma$ errors) for the Fe-K$\alpha$ line behind the continuum, which is consistent with the location of the BLR determined in optical spectroscopic reverberation mapping during the type-1 (bright) phase. This finding shows that the BLR materials remained at the same location without emitting optical broad-lines during the type-2 phase. Considering the drastic decrease of the radiation during the type-transition, our result is possibly inconsistent with the hotly-discussed formation models of the BLR which propose that the radiative pressure from an accretion disk should be the main driving force.

We study the Fourier time-lags due to the Comptonization of disc-emitted photons in a spherical, uniform, and stationary X-ray corona, which located on the rotational axis of the black hole. We use Monk, a general relativistic Monte-Carlo radiative transfer code, to calculate Compton scattering of photons emitted by a thin disc with a Novikov-Thorne temperature profile. We find that the model time-lags due to Comptonization remain constant up to a characteristic frequency and then rapidly decrease to zero at higher frequencies. We provide equations which can be used to determine the time-lags and cross spectra for a wide range of values for the corona radius, temperature, optical depth, height, and for various accretion rates and black hole masses. We also provide an equation for the X-ray luminosity of a single corona, as a function of the its characteristics and location above the disc. Remarkably, the observed X-ray time-lags of nearby, bright active galaxies can be successfully reproduced by inverse Comptonization process of multiple dynamic coronae.

Turbulence in protoplanetary disks plays an important role in dust evolution and planetesimal formation. The vertical shear instability (VSI) is one of the candidate hydrodynamic mechanisms that can generate turbulence in the outer disk regions. The VSI requires rapid gas cooling in addition to vertical shear. A linear stability analysis suggests that the VSI may not operate around the midplane where gas cooling is inefficient. In this study, we investigate the nonlinear outcome of the VSI in disks with a linearly VSI-stable midplane region. We perform two-dimensional global hydrodynamical simulations of an axisymmetric disk with vertically varying cooling times. The vertical cooling time profile determines the thicknesses of the linearly VSI-stable midplane layer and unstable layers above and below the midplane. We find that the thickness of the midplane stable layer determines the vertical structure of VSI-driven turbulence in the nonlinear saturated state. We identify two types of final saturated state: (1) T states characterized by vertical turbulent motion penetrating into the VSI-stable midplane layer and (2) pT states characterized by turbulent motion confined in the unstable layers. The pT states are realized when the midplane VSI-stable layer is thicker than two gas scale heights. We also find that the VSI-driven turbulence is largely suppressed at all heights when the VSI-unstable region lying above and below the midplane is thinner than two gas scale heights. We present empirical formulas that predict the strength of VSI-driven turbulence as a function of the thicknesses of the unstable and stable layers. These formulas will be useful for studying how VSI-driven turbulence and dust grains controlling the disk cooling efficiency evolve simultaneously.

Flux-resolved X-ray spectroscopy is widely adopted to investigate the spectral variation of a target between various flux levels. In many cases it is done through horizontally splitting a single light curve into multiple flux levels with certain count rate threshold(s). In this work we point out there are two hidden biases in this approach which could affect the spectral analyses under particular circumstances. The first is that, when Poisson fluctuations of the source counts in light curve bins are non-negligible compared with the intrinsic variation, this approach would over-estimate (under-estimate) the intrinsic average flux level of the high (low) state. The second bias is that, when the Poisson fluctuations of the background count rate is non-negligible, the background spectrum of the high (low) state would be under-estimated (over-estimated), thus yielding biased spectral fitting parameters. We take NuSTAR spectra for example to illustrate the effects of the biases, and particularly, how the measurements of the coronal temperature in AGNs would be biased. We present a toy method to assess the significance of such biases, and approaches to correct for them when necessary.

We present a sample of 2700 Ap stars in LAMOST DR9. The candidates are first selected to be in a temperature range typical of Ap stars by using the $BP$-$RP$ color index from Gaia DR3. Then the 5200\,\AA\ flux depression features characteristic of Ap stars are visually checked in LAMOST DR9 spectra. The detailed spectral features are given by applying a modified spectral classification program, MKCLASS. Stellar parameters of these Ap stars such as $T_{\rm eff}$, $\log g$, [Fe/H], [Si/H], and $v{\sin}i$ are either extracted from a hot star catalog or derived through empirical relations and then a statistical analysis is carried out. The evolutionary stages are also discussed. Finally, we discuss the rotation and pulsation features of those who have TESS or Kepler light curves. Among these Ap stars we find 7 new rotation variables, 1 new roAp star, and new $\delta$ Scuti pulsation of a previously known roAp star.

In this paper, we provide the first computations for the distortion transfer functions of the cosmic microwave background (CMB) in the perturbed Universe, following up on paper I and II in this series. We illustrate the physical effects inherent to the solutions, discussing and demonstrating various limiting cases for the perturbed photon spectrum. We clarify the relationship between distortion transfer functions and the photon spectrum itself, providing the machinery that can then compute constrainable CMB signal power spectra including spectral distortions for single energy injection and decaying particle scenarios. Our results show that the $\mu \times T$ and $y\times T$ power spectra reach levels that can be constrained with current and future CMB experiments without violating existing constraints from COBE/FIRAS. The amplitude of the cross-correlation signal directly depends on the average distortion level, therefore establishing a novel fundamental link between the state of the primordial plasma from redshift $10^3 \lesssim z\lesssim 3\times 10^6$ and the frequency-dependent CMB sky. This provides a new method to constrain average early energy release using CMB imagers. As an example we derive constraints on single energy release and decaying particle scenarios. This shows that LiteBIRD may be able to improve the energy release limits of COBE/FIRAS by up to a factor of $\simeq 2.5$, while PICO could tighten the constraints by more than one order of magnitude. The signals considered here could furthermore provide a significant challenge to reaching cosmic variance-limited constraints on primordial non-Gaussianity from distortion anisotropy studies. Our work further highlights the immense potential for a synergistic spectroscopic approach to future CMB measurements and analyses.

In this study, we employ a cloud-resolving model (CRM) to investigate how gravity influences convection and clouds in a small-domain (96 km by 96 km) radiative-convective equilibrium (RCE). Our experiments are performed with a horizontal grid spacing of 1 km, which can resolve large (> 1 km$^2$) convective cells. We find that under a given stellar flux, sea surface temperature increases with decreasing gravity. This is because a lower-gravity planet has larger water vapor content and more clouds, resulting in a larger clear-sky greenhouse effect and a stronger cloud warming effect in the small domain. By increasing stellar flux under different gravity values, we find that the convection shifts from a quasi-steady state to an oscillatory state. In the oscillatory state, there are convection cycles with a period of several days, comprised of a short wet phase with intense surface precipitation and a dry phase with no surface precipitation. When convection shifts to the oscillatory state, water vapor content and high-level cloud fraction increase substantially, resulting in rapid warming. After the transition to the oscillatory state, the cloud net positive radiative effect decreases with increasing stellar flux, which indicates a stabilizing climate effect. In the quasi-steady state, the atmospheric absorption features of CO$_2$ are more detectable on lower-gravity planets because of their larger atmospheric heights. While in the oscillatory state, the high-level clouds mute almost all the absorption features, making the atmospheric components hard to be characterized.

We use a new approach based on self-supervised deep learning networks originally applied to transparency separation in order to simultaneously extract the components of the extragalactic submillimeter sky, namely the Cosmic Microwave Background (CMB), the Cosmic Infrared Background (CIB), and the Sunyaev-Zel'dovich (SZ) effect. In this proof-of-concept paper, we test our approach on the WebSky extragalactic simulation maps in a range of frequencies from 93 to 545 GHz, and compare with one of the state-of-the-art traditional method MILCA for the case of SZ. We compare first visually the images, and then statistically the full-sky reconstructed high-resolution maps with power spectra. We study the contamination from other components with cross spectra, and we particularly emphasize the correlation between the CIB and the SZ effect and compute SZ fluxes around positions of galaxy clusters. The independent networks learn how to reconstruct the different components with less contamination than MILCA. Although this is tested here in ideal case (without noise, beams, nor foregrounds), this method shows good potential for application in future experiments such as Simons Observatory (SO) in combination with the Planck satellite.

The method of time delay interferometry (TDI) is proposed to cancel the laser noise in space-borne gravitational-wave detectors. Among all different TDI combinations, the most commonly used ones are the orthogonal channels A, E and T, where A and E are signal-sensitive and T is signal-insensitive. Meanwhile, for the detection of stochastic gravitational-wave background, one needs to introduce the overlap reduction function to characterize the correlation between channels. For the calculation of overlap reduction function, it is often convenient to work in the low-frequency approximation, and assuming the equal-arm Michelson channels. However, if one wishes to work on the overlap reduction function of $\rm A/E$ channels, then the low-frequency approximation fails. We derive the exact form of overlap reduction function for $\rm A/E$ channels. Based on the overlap reduction function, we calculate the sensitivity curves of TianQin, TianQin I+II and TianQin + LISA. We conclude that the detection sensitivity calculated with $\rm A/E$ channels is mostly consistent with that obtained from the equal-arm Michelson channels.

The Indian Consortium of Cosmologists has proposed a fourth-generation CMB space mission aiming to detect the primordial B-mode of Cosmic Microwave Background(CMB) polarization. The detection of this faint signal is very challenging as it is deeply buried under the dominant astrophysical foreground emissions of the thermal dust and the synchrotron. To facilitate the adequate subtraction of thermal dust, the instrument design of ECHO has included nine dust-dominated high frequency channels in the range of 220-850 GHz. In this work, we closely re-examine the utility of the high frequency ECHO bands using the Needlet Internal Linear Combination(NILC) component separation method. We consider three dust models; a dust SED with single modified black body(MBB) emission law, a physical dust model and a multilayer dust model with frequency-frequency decorrelation. We find that the ECHO bands in the range of 220-390 GHz are most crucial for effective dust removal. The addition of high frequency channels in the 600-850 GHz range leads to only a slight improvement in the sensitivity of ECHO for the single MBB model and no significant improvement for the more complex physical and multilayer dust models.

Magnetic fields play a key role in driving a broad range of dynamic phenomena in the atmospheres of the Sun and other stars. Routine and accurate measurements of the magnetic fields at all the atmospheric layers are of critical importance to understand these magnetic activities, but in the solar and stellar coronae such a measurement is still a challenge due to the weak field strength and the high temperature. Recently, a magnetic-field-induced transition (MIT) of Fe X at 257.26 {\AA} has been proposed for the magnetic field measurements in the solar and stellar coronae. In this review, we present an overview of recent progresses in the application of this method in astrophysics. We start by introducing the theory underlying the MIT method and reviewing the existing atomic data critical for the spectral modeling of Fe X lines. We also discuss the laboratory measurements that verify the potential capability of the MIT technique as a probe for diagnosing the plasma magnetic fields. We then continue by investigating the suitability and accuracy of solar and stellar coronal magnetic field measurements based on the MIT method through forward modeling. Furthermore, we discuss the application of the MIT method to the existing spectroscopic observations obtained by the Extreme-ultraviolet Imaging Spectrometer onboard Hinode. This novel technique provides a possible way for routine measurements of the magnetic fields in the solar and stellar coronae, but still requires further efforts to improve its accuracy. Finally, the challenges and prospects for future research on this topic are discussed.

Galaxies throughout the last 12 Gyr of cosmic time follow a single, universal fundamental plane that relates their star-formation rates (SFRs), stellar masses ($M_\star$) and chemical abundances. Deviation from these fundamental scaling relations would imply a drastic change in the processes that regulate galaxy evolution. Observations have hinted at the possibility that this relation may be broken in the very early universe. However, until recently, chemical abundances of galaxies could be only measured reliably as far back as redshift $z = 3.3$. With JWST, we can now characterize the SFR, $M_\star$, and gas-phase metallicity of galaxies during the first few hundred million years after the Big Bang, at redshifts $z\approx 7-10$. Here we show that galaxies at this epoch follow universal SFR-$M_\star$ main-sequence and mass-metallicity scaling relations, but their chemical abundance is a factor of three lower than expected from the fundamental plane of later galaxies. Compared to state-of-the-art simulations, these findings suggest a more rapid onset of galaxy assembly and star formation than previously anticipated, and further indicate that galaxies at this time are still intimately connected with the intergalactic medium and subject to continuous infall of pristine gas which effectively dilutes their metal abundances.

Aims. We introduce a novel way to identify new compact hierarchical triple stars by exploiting the huge potential of Gaia DR3 and also its future data releases. We aim to increase the current number of compact hierarchical triples significantly. Methods. We utilize several eclipsing binary catalogs from different sky surveys totaling more than 1 million targets for which we search for Gaia DR3 Non-single Star orbital solutions with periods substantially longer than the eclipsing periods of the binaries. Those solutions in most cases should belong to outer orbits of tertiary stars in those systems. We also try to validate some of our best-suited candidates using TESS eclipse timing variations. Results. We find 403 objects with suitable Gaia orbital solutions of which 27 are already known triple systems. This makes 376 newly identified hierarchical triple system candidates in our sample. We analyze the cumulative probability distribution of the outer orbit eccentricities and find that it is very similar to the ones found by earlier studies based on the observations of the Kepler and OGLE missions. We found measurable non-linear eclipse timing variations or third-body eclipses in the TESS data for 192 objects which we also consider to be confirmed candidates. Out of these, we construct analytical light-travel time effect models for the eclipse timing variations of 22 objects with well-sampled TESS observations. We compare the outer orbital parameters from our solutions with the ones from the Gaia solutions and find that the most reliable orbital parameter is the orbital period, while the values of the other parameters should be used with caution.

The appearance of dark sunspots over the solar photosphere is not considered to be symmetric between the northern and southern hemispheres. Among the different conclusions obtained by several authors, we can point out that the North-South asymmetry is a real and systematic phenomenon and is not due to random variability. In the present work, we selected the sunspot area data of a sample of 13 solar cycles divided by hemisphere extracted from the Marshall Space Flight Centre (MSFC) database to investigate the behavior of probability distributions using an out-of-equilibrium statistical model a.k.a non-extensive statistical mechanics. Based on this statistical framework, we obtained that the non-extensive entropic parameter $q$ has a semi-sinusoidal variation with a period of $\sim$22 year (Hale cycle). Among the most important results, we can highlight that the asymmetry index $q(A)$ revealed the dominance of the northern hemisphere against the southern one. Thus, we concluded that the parameter $q(A)$ can be considered an effective measure for diagnosing long-term variations of the solar dynamo. Finally, our study opens a new approach to investigating solar variability from the nonextensive perspective.

We present a photometric halo mass estimation technique for local galaxies that enables us to establish the stellar mass-halo mass (SMHM) relation down to stellar masses of 10$^5$ M$_\odot$. We find no detectable differences among the SMHM relations of four local galaxy clusters or between the cluster and field relations and we find agreement with extrapolations of previous SMHM relations derived using abundance matching approaches. We fit a power law to our empirical SMHM relation and find that for adopted NFW dark matter profiles and for M$_* < 10^9$ M$_\odot$, the halo mass is M$_h = 10^{10.35\pm0.02}({\rm M}_*/10^8 {\rm M}_\odot)^{0.63\pm0.02}$. The normalisation of this relation is susceptible to systematic modelling errors that depend on the adopted dark matter potential and the quoted uncertainties refer to the uncertainties in the median relation. For galaxies with M$_* < 10^{9}$ M$_\odot$ that satisfy our selection criteria, the scatter about the fit in $M_h$, including uncertainties arising from our methodology, is 0.3 dex. Finally, we place lower luminosity Local Group galaxies on the SMHM relationship using the same technique, extending it to M$_* \sim 10^3$ M$_\odot$ and suggest that some of these galaxies show evidence for additional mass interior to the effective radius beyond that provided by the standard dark matter profile. If this mass is in the form of a central black hole, the black hole masses are in the range of intermediate mass black holes, $10^{(5.7\pm0.6)}$ M$_\odot$, which corresponds to masses of a few percent of M$_h$, well above values extrapolated from the relationships describing more massive galaxies.

TIC033834484 and TIC309658435 are long-period pulsating subdwarf B star, which were observed extensively (675 and 621 days, respectively) by the Transiting Exoplanet Survey Satellite (TESS). The high-precision photometric light curve reveals the presence of more than 40 pulsation modes including both stars. All the oscillation frequencies that we found are associated with gravity (g)-mode pulsations, with frequencies spanning from 80 $\mu$Hz (2 500 s) to 400 $\mu$Hz (12 000 s). We utilize the asteroseismic tools including asymptotic period spacings and rotational frequency multiplets in order to identify the pulsational modes. We found dipole (l = 1) mode sequences for both targets and calculate the mean period spacing of dipole modes ($\Delta P_{l=1}$), which allows us to identify the modes. Frequency multiplets provide a rotation period of about 64 d for TIC033834484. From follow-up ground-based spectroscopy, we find that TIC\,033834484 has an effective temperature of 24 210 K (140), a surface gravity of logg = 5.28 (03) and TIC309658435 has an effective temperature of 25 910 K (150), a surface gravity of logg = 5.48 (03).

We present a new X-ray spectroscopic study of $22$ luminous ($2\times10^{45}\lesssim L_{\rm bol}\rm /erg\,s^{-1} \lesssim 2\times10^{46}$) active galactic nuclei (AGNs) at intermediate-redshift ($0.1 \lesssim z \lesssim 0.4$), as part of the SUpermassive Black hole Winds in the x-rAYS (SUBWAYS) sample, mostly composed of quasars (QSOs) and type\,1 AGN. Here, 17 targets were observed with \textit{XMM-Newton} between 2019--2020 and the remaining 5 are from previous observations. The aim of this large campaign ($1.45\,\rm Ms$ duration) is to characterise the various manifestations of winds in the X-rays driven from supermassive black holes in AGN. In this paper we focus on the search and characterization of ultra-fast outflows (UFOs), which are typically detected through blueshifted absorption troughs in the Fe\,K band ($E>7\,\rm keV$). By following Monte Carlo procedures, we confirm the detection of absorption lines corresponding to highly ionised iron (e.g., Fe\,\textsc{xxv}\,H$\alpha$, Fe\,\textsc{xxvi}\,Ly$\alpha$) in 7/22 sources at the $\gtrsim95\%$ confidence level (for each individual line). The global combined probability of such absorption features in the sample is $>99.9\%$. The SUBWAYS campaign extends at higher luminosity and redshifts than previous local studies on Seyferts, obtained using \xmm and \suzaku observations. We find a UFO detection fraction of $\sim30\%$ on the total sample that is in agreement with the previous findings. This work independently provides further support for the existence of highly-ionised matter propagating at mildly relativistic speed ($\gtrsim0.1c$) in a considerable fraction of AGN over a broad range of luminosities, which is expected to play a key role in the self-regulated AGN feeding-feedback cycle, as also supported by hydrodynamical multiphase simulations.

We present a UV spectroscopic study of ionized outflows in 21 active galactic nuclei (AGN), observed with the HST. The targets of the SUBWAYS sample were selected with the aim to probe the parameter space of the underexplored AGN between the local Seyfert galaxies and the luminous quasars at high redshifts. Our targets, spanning redshifts of 0.1-0.4 and bolometric luminosities (L_bol) of 10^45-10^46 erg/s, have been observed with a large multi-wavelength campaign. Here, we model the UV spectra and look for different types of AGN outflows. We find that 60% of our targets show a presence of outflowing H I absorption, while 40% exhibit ionized outflows seen as absorption by either C IV, N V, or O VI. This is comparable to the occurrence of ionized outflows seen in the local Seyfert galaxies. All UV absorption lines in the sample are relatively narrow, with outflow velocities reaching up to -3300 km/s. We did not detect any UV counterparts to the X-ray ultra-fast outflows (UFOs), most likely due to their being too highly ionized. However, all SUBWAYS targets with an X-ray UFO demonstrate the presence of UV outflows at lower velocities. We find significant correlations between the column density (N) of the UV ions and L_bol of the AGN, with N of H I decreasing with L_bol, while N of O VI is increasing with L_bol. This is likely to be a photoionization effect, where toward higher AGN luminosities, the wind becomes more ionized, resulting in less absorption by neutral or low-ionization ions and more absorption by high-ionization ions. In addition, we find that N of the UV ions decreases as their outflow velocity increases. This may be explained by a mechanical power that is evacuating the UV-absorbing medium. Our observed relations are consistent with multiphase AGN feeding and feedback simulations indicating that a combination of both radiative and mechanical processes are in play.

Background. Relative astrometry at or below the micro-arcsec level with a 1m class space telescope has been repeatedly proposed as a tool for exo-planet detection and characterization, as well as for several topics at the forefront of Astrophysics and Fundamental Physics. Aim. This paper investigates the potential benefits of an instrument concept based on an annular field of view, as compared to a traditional focal plane imaging a contiguous area close to the telescope optical axis. Method. Basic aspects of relative astrometry are reviewed as a function of the distribution on the sky of reference stars brighter than G = 12 mag (from Gaia EDR3). Statistics of field stars for targets down to G = 8 mag is evaluated by analysis and simulation. Results. Observation efficiency benefits from prior knowledge on individual targets, since source model is improved with few measurements. Dedicated observations (10-20 hours) can constrain the orbital inclination of exoplanets to a few degrees. Observing strategy can be tailored to include a sample of stars, materialising the reference frame, sufficiently large to average down the residual catalogue errors to the desired microarcsec level. For most targets, the annular field provides typically more reference stars, by a factor four to seven in our case, than the conventional field. The brightest reference stars for each target are up to 2 mag brighter. Conclusions. The proposed annular field telescope concept improves on observation flexibility and/or astrometric performance with respect to conventional designs. It appears therefore as an appealing contribution to optimization of future relative astrometry missions.

I present the first constraints on decaying cold dark matter (DCDM) models thanks to the effective field theory of large-scale structure (EFTofLSS) applied to BOSS-DR12 data. I consider two phenomenological models of DCDM: i) a model where a fraction $f_{\rm dcdm}$ of cold dark matter (CDM) decays into dark radiation (DR) with a lifetime $\tau$; ii) a model (recently suggested as a potential resolution to the $S_8$ tension) where all the CDM decays with a lifetime $\tau$ into DR and a massive warm dark matter (WDM) particle, with a fraction $\varepsilon$ of the CDM rest mass energy transferred to the DR. I discuss the implications of the EFTofLSS constraints for the DCDM model suggested to resolve the $S_8$ tension.

Context: A full understanding of the planet and moon formation process requires observations that probe the circumplanetary environment of accreting giant planets. The mid-infrared ELT imager and spectrograph (METIS) will provide a unique capability to detect warm-gas emission lines from circumplanetary disks. Aims: We aim to demonstrate the capability of the METIS instrument on the Extremely Large Telescope (ELT) to detect circumplanetary disks (CPDs) with fundamental v=1-0 transitions of $^{12}$CO from 4.5-5 $\mu$m. Methods: We consider the case of the well-studied HD 100546 pre-transitional disk to inform our disk modeling approach. We use the radiation-thermochemical disk modeling code ProDiMo to produce synthetic spectral channel maps. The observational simulator SimMETIS is employed to produce realistic data products with the integral field spectroscopic (IFU) mode. Results: The detectability of the CPD depends strongly on the level of external irradiation and the physical extent of the disk, favoring massive (~10 M$_{\rm J}$) planets and spatially extended disks with radii approaching the planetary Hill radius. The majority of $^{12}$CO line emission originates from the outer disk surface, and thus the CO line profiles are centrally peaked. The planetary luminosity does not contribute significantly to exciting disk gas line emission. If CPDs are dust-depleted, the $^{12}$CO line emission is enhanced as external radiation can penetrate deeper into the line emitting region. Conclusions: UV-bright star systems with pre-transitional disks are ideal candidates to search for CO-emitting CPDs with ELT/METIS. METIS will be able to detect a variety of circumplanetary disks via their fundamental $^{12}$CO ro-vibrational line emission in only 60 s of total detector integration time.

We present DABS (Database of Accreting Binary Simulations), an open-access database of modelled Low Mass X-ray Binaries (LMXBs). DABS has been created using evolutionary tracks of neutron star and black hole LMXBs, spanning a large set of initial conditions for the accretor mass, donor mass, and orbital period. The LMXBs are evolved with the Convection and Rotation Boosted Magnetic Braking prescription. The most important asset of this online database is the tool PEAS (Progenitor Extractor for Accreting Systems). This tool can be used to predict the progenitors of any user-entered LMXB system and view their properties before the start of mass transfer. This prediction can facilitate preliminary searches for the progenitors of observed LMXBs, which can help in streamlining further detailed analyses. The PEAS tool can also be used to constrain population synthesis techniques that specialize in supernova kicks in binaries and common envelope outcomes.

In recent years, radio interferometric observations have achieved high accuracy in determining the absolute values of trigonometric parallaxes and proper motions of maser radiation sources and radio stars. The error in determining the trigonometric parallaxes of these objects averages about 10 microarcseconds, which allows us to confidently study the geometric and kinematic properties of the distribution of stars located at great distances from the Sun, up to the center of the Galaxy. This article provides an overview of the main results of studying the structure and kinematics of the Galaxy, which were obtained by various scientific teams using VLBI observations of masers and radio stars. The main attention is paid to the results of studying the Galaxy obtained by the authors of this work.

Young planets embedded in protoplanetary discs (PPDs) excite spiral density waves, which propagate, shock and deposit angular momentum in the disc. This results in gap opening around the planetary orbit, even for low (sub-thermal) mass planets, provided that the effective viscosity in the disc is low. The edges of these planet-induced gaps are known to be prone to emergence of observable vortices via the Rossby Wave Instability (RWI). We study timescales for the development of vortices driven by low mass planets in inviscid discs. We employ a recently developed semi-analytical theory of vortensity production by the planet-driven shock to predict vortensity evolution near the planet, from which we derive the radial profile of the planet-induced gap as a function of time (this procedure can have multiple other uses, e.g. to study dust trapping, suppression of pebble accretion, etc.). We then analyze the linear stability of the gap edges against the RWI, obtaining the timescales for the first appearance of unstable modes and (later) fully developed vortices at gap edges. We present useful formulae for these timescales as functions of planetary and disc parameters and provide their physical justification. We also thoroughly test our semi-analytical framework against high resolution 2D hydrodynamic simulations, confirming the accuracy of our theoretical predictions. We discuss ways in which our semi-analytical framework can be extended to incorporate additional physics, e.g. planetary accretion, migration, and non-zero disc viscosity. Our results can be used to interpret observations of PPDs and to predict emergence of vortices in simulations.

Extreme high-frequency peaked BL Lacs (EHBLs) are characterized by a synchrotron peak frequency exceeding $10^{17}$ Hz and a second peak that can be in the energy range of few GeVs to several TeVs. The MAGIC telescopes detected multi-TeV gamma-rays on April 19, 2018 for the first time from the EHBL PGC 2402248 which was simultaneously observed in multiwavelength by several other instruments. The broad band spectral energy distribution of the source is conventionally modelled using the leptonic and the hadronic models. Due to the success of the photohadronic model in interpreting the enigmatic very high-energy (VHE) flaring events from many high-energy blazars, we extend this model to explain the VHE events from PGC 2402248 observed by MAGIC telescopes and compare our results with other models. We conclude that the photohadronic fits are comparable and even fare better than most other models. Furthermore, we show that the spectrum is not hard and is in a low emission state. The estimated bulk Lorentz factor for this flaring event is found to be $\lesssim 34$.

Models of the origin of astrophysical neutrinos with energies from TeVs to PeVs are strongly constrained by multimessenger observations and population studies. Recent results point to statistically significant associations between these neutrinos and active galactic nuclei (AGN) selected by their radio flux observed with very-long-baseline interferometry (VLBI). This suggests that the neutrinos are produced in central parsecs of blazars, AGN with relativistic jets pointing to the observer. However, conventional AGN models tend to explain only the highest-energy part of the neutrino flux observationally associated with blazars. Here we discuss in detail how the neutrinos can be produced in the part of an AGN giving the dominant contribution to the VLBI radio flux, the radio core located close to the jet base. Physical conditions there differ both from the immediate environment of the central black hole and from the plasma blobs moving along the jet. Required neutrino fluxes, considerably smaller than those of photons, can be produced in interactions of relativistic protons, accelerated closer to the black hole, with radiation in the core.

Due to the first results on astrophysical X-ray polarization provided by \textit{IXPE} observatory, the interest in wavelength-dependent synchrotron polarization of BL Lac type objects increases. This paper presents the results of multi-band optical observations of the well-known blazar named BL Lac ($z=0.069$) in polarized light. It was shown that the object's emission, regardless of its phase of activity, is characterized by the intraday variability of brightness and polarization with changes occurring on a time-scale of up to 1.5 hours without any stable oscillation period. Polarimetric observations in the different optical bands show that the degree and angle of polarization of the blazar depend on the wavelength, and the maximum chromatism, as well as the maximum observed polarization degree, was detected during the minimum brightness state; during the flare state, the polarization chromatism changed along with the flux gradient on the time-scale of an hour. Qualitatively, such behaviour can be described by the shock-in-jet model, yet the chromatism amplitude and its rapid changes differ significantly from the model predictions and challenge the numerical calculations.

Context: Accretion at planetary-mass companions (PMCs) suggests the presence of a protoplanetary disc in the system, likely accompanied by a circumplanetary disc. High-resolution spectroscopy of accreting PMCs is very difficult due to their proximity to bright host stars. For well-separated companions however, such spectra are feasible and are unique windows into accretion. Aims: We have followed up on our observations of the ~40-Myr, and still accreting, circumbinary PMC Delorme 1 (AB)b. We used high-resolution spectroscopy to characterise the accretion process further by accessing the wealth of emission lines in the near-UV. Methods: We have used the UVES spectrograph on the ESO VLT/UT2 to obtain R_lambda ~ 50000 spectroscopy, at 330-452 nm, of Delorme 1 (AB)b. After separating the emission of the companion from that of the M5 low-mass binary, we performed a detailed emission-line analysis, which included planetary accretion shock modelling. Results: We reaffirm ongoing accretion in Delorme 1 (AB)b and report the first detections in a (super-Jovian) protoplanet of resolved hydrogen line emission in the near-UV (H-gamma, H-delta, H-epsilon, H8 and H9). We tentatively detect H11, H12, He I and Ca II H/K. The analysis strongly favours a planetary accretion shock with a line-luminosity-based accretion rate dM/dt = 2e-8 MJ/yr. The lines are asymmetric and are well described by sums of narrow and broad components with different velocity shifts. The overall line shapes are best explained by a pre-shock velocity v0=170+-30 km/s, implying a planetary mass M_P=13+-5 MJ, and number densities n0~1e13/cm^3 or n0~1e11/cm^3. The higher density implies a small line-emitting area of ~1 % relative to the planetary surface. This favours magnetospheric accretion, a case potentially strengthened by the presence of blueshifted emission in the asymmetrical profiles. Conclusions: ABRV.

We study the linear properties, nonlinear saturation and a steady, strongly nonlinear state of the Parker instability in galaxies. We consider magnetic buoyancy and its consequences with and without cosmic rays. Cosmic rays are described using the fluid approximation with anisotropic, non-Fickian diffusion. To avoid unphysical constraints on the instability (such as boundary conditions often used to specify an unstable background state), nonideal MHD equations are solved for deviations from a background state representing an unstable magnetohydrostatic equilibrium. We consider isothermal gas and neglect rotation. The linear evolution of the instability is in broad agreement with earlier analytical and numerical models; but we show that most of the simplifying assumptions of the earlier work do not hold, such that they provide only a qualitative rather than quantitative picture. In its nonlinear stage the instability has significantly altered the background state from its initial state. Vertical distributions of both magnetic field and cosmic rays are much wider, the gas layer is thinner, and the energy densities of both magnetic field and cosmic rays are much reduced. The spatial structure of the nonlinear state differs from that of any linear modes. A transient gas outflow is driven by the weakly nonlinear instability as it approaches saturation.

We explore the so-called softness diagram -- whose main function is to provide the hardness of the ionizing radiation in star-forming regions -- in order to check whether hot and old low-mass evolved stars (HOLMES) are significant contributors to the ionization within star-forming regions, as suggested by previous MaNGA data analyses. We used the code HCm-Teff to derive both the ionization parameter and the equivalent effective temperature (T*), adopting models of massive stars and planetary nebulae (PNe), and exploring different sets of emission lines in the softness diagram to figure out the main causes of the observed differences in the softness parameter in the MaNGA and CHAOS star-forming region samples. We find that the fraction of regions with a resulting T* > 60 kK, which are supposedly ionised by sources harder than massive stars, is considerably larger in the MaNGA (66%) than in the CHAOS (20%) sample when the [SII] $\lambda\lambda$ 6716,6731 emission lines are used in the softness diagram. However, the respective fractions of regions in this regime for both samples are considerably reduced (20% in MaNGA and 10% in CHAOS) when the [NII] emission line at $\lambda$ 6584 is used instead. This may indicate that diffuse ionised gas (DIG) contamination in the lower resolution MaNGA data is responsible for artificially increasing the measured T* as opposed to there being a predominant role of HOLMES in the HII regions.

X-ray observations of several kiloparsec-scale extragalactic jets favour a synchrotron origin. The short cooling times of the emitting electrons requires distributed acceleration of electrons up to sub-PeV energies. In a previous paper, we found that this can be self-consistently explained by a shear acceleration model, where particles are accelerated to produce power-law spectra with a spectral index being determined mainly by the velocity profile and turbulence spectrum. In this paper, we perform 3D relativistic magneto-hydrodynamic simulations to investigate the formation of a spine-sheath structure and the development of turbulence for a relativistic jet propagating into a static cocoon. We explore different spine velocities and magnetic field profiles with values being chosen to match typical Fanaroff-Riley type I/II jets. We find that in all cases a sheath is generated on the interface of the spine and the cocoon mainly due to the Kelvin-Helmholtz instability. The large scale velocity profile in the sheath is close to linear. Turbulence develops in both the spine and the sheath, with a turbulent velocity spectrum consistent with Kolmogorov-scaling. The implications for shear particle acceleration are explored, with a focus on the particle spectral index.

Context. Large and complete galaxy cluster samples can be used to infer cosmological parameter constraints from number count measurements. Key to their interpretation is the availability of accurately calibrated estimates of the halo mass function from cosmological simulations. Galaxy cluster masses are usually defined as the mass within a spherical region enclosing a given matter overdensity (in units of the critical density). However, this may differ from the mass definition of the numerical halo catalogues that are used to calibrate the halo mass function. Aims. In this article, we present a generic non parametric formalism that allows one to accurately map the halo mass function between different mass overdensity definitions using the distribution of halo sparsities defined as the ratios of both masses. We show that changing mass definitions reduces to modelling the distribution of halo sparsities. Methods. Using standard transformation rules of random variates, we derive relations between the halo mass function at different overdensities and the distribution of halo sparsities. Results. We show that these relations reproduce the N-body halo mass functions from the Uchuu simulation within the statistical errors at a few percent level. Furthermore, these relations allow one to relate the halo mass functions at different overdensities to parametric descriptions of the halo density profile. In particular, we will discuss the case of the concentration-mass relation of the Navarro-Frenk-White profile. Finally, we will show that the use of such relations allows to predict the distribution of sparsities of a sample of haloes of a given mass, thus opening the way to inferring cosmological constraints from individual galaxy cluster sparsity measurements.

The Cosmological Principle asserts that on sufficiently large scales the universe is homogeneous and isotropic on spatial slices. Challenging this principle requires a departure from the FLRW ansatz. In this paper we analyse the cosmological evolution of spatially homogeneous but anisotropic universes in which only two of the three space dimensions are maximally symmetric, namely the closed Kantowski-Sachs universe and the open axisymmetric Bianchi type III universe. These models are characterised by two scale factors and we study their evolution in universes with radiation, matter and a cosmological constant. In all cases, the two scale factors evolve differently and this anisotropy leads to a lensing effect in the propagation of light. We derive explicit formulae for computing redshifts, angular diameter distances and luminosity distances and discuss the predictions of these models in relation to observations for type Ia supernovae and the CMB.

Though the global atmospheres of hot Jupiters have been extensively studied using phase curve observations, the level of time variability in these data is not well constrained. To investigate possible time variability in a planetary phase curve, we observed two full orbit phase curves of the hot Jupiter WASP-43b at 4.5 microns using the Spitzer Space Telescope, and reanalyzed a previous 4.5 micron phase curve from Stevenson et al. (2017). We find no significant time variability between these three phase curves, which span timescales of weeks to years. The three observations are best fit by a single phase curve with an eclipse depth of 3907 +- 85 ppm, a dayside integrated brightness temperature of 1479 +- 13 K, a nightside integrated brightness temperature of 755 +- 46 K, and an eastward-shifted peak of 10.4 +- 1.8 degrees. To model our observations, we performed 3D GCM simulations of WASP-43b with simple cloud models of various vertical extents. In comparing these simulations to our observations, we find that WASP-43b likely has a cloudy nightside that transitions to a relatively cloud-free dayside. We estimate that any change in WASP-43bs vertical cloud thickness of more than 3 pressure scale heights is inconsistent with our observed upper limit on variation. These observations, therefore, indicate that WASP-43bs clouds are stable in their vertical and spatial extent over timescales up to several years. These results strongly suggest that atmospheric properties derived from previous, single Spitzer phase curve observations of hot Jupiters likely show us the equilibrium properties of these atmospheres.

We construct boson star configurations in quantum field theory using the semiclassical gravity approximation. Restricting our attention to the static case, we show that the semiclassical Einstein-Klein-Gordon system for a {\it single real quantum} scalar field whose state describes the excitation of $N$ {\it identical particles}, each one corresponding to a given energy level, can be reduced to the Einstein-Klein-Gordon system for $N$ {\it complex classical} scalar fields. Particular consideration is given to the spherically symmetric static scenario, where energy levels are labeled by quantum numbers $n$, $\ell$ and $m$. When all particles are accommodated in the ground state $n=\ell=m=0$, one recovers the standard static boson star solutions, that can be excited if $n\neq 0$. On the other hand, for the case where all particles have fixed radial and total angular momentum numbers $n$ and $\ell$, with $\ell\neq 0$, but are homogeneously distributed with respect to their magnetic number $m$, one obtains the $\ell$-boson stars, whereas when $\ell=m=0$ and $n$ takes multiple values, the multi-state boson star solutions are obtained. Further generalizations of these configurations are presented, including the multi-$\ell$ multi-state boson stars, that constitute the most general solutions to the $N$-particle, static, spherically symmetric, semiclassical real Einstein-Klein-Gordon system, in which the total number of particles is definite. In spite of the fact that the same spacetime configurations also appear in multi-field classical theories, in semiclassical gravity they arise naturally as the quantum fluctuations associated with the state of a single field describing a many-body system. Our results could have potential impact on direct detection experiments in the context of ultralight scalar field/fuzzy dark matter candidates.

Fluctuations play a critical role in cosmology. They are relevant across a range of phenomena from the dynamics of inflation to the formation of structure. In many cases, these fluctuations are coarse grained and follow a Gaussian distribution as a consequence of the Central Limit Theorem. Yet, some classes of observables are dominated by rare fluctuations and are sensitive to the details of the underlying microphysics. In this paper, we argue that the Large Deviation Principle can be used to diagnose when one must to appeal to the fundamental description. Concretely, we investigate the regime of validity for the Fokker-Planck equation that governs Stochastic Inflation. For typical fluctuations, this framework leads to the central limit-type behavior expected of a random walk. However, fluctuations in the regime of the Large Deviation Principle are determined by instanton-like saddle points accompanied by a new energy scale. When this energy scale is above the UV cutoff of the EFT, the tail is only calculable in the microscopic description. We explicitly demonstrate this phenomenon in the context of determining the phase transition to eternal inflation, the distribution of scalar field fluctuations in de Sitter, and the production of primordial black holes.

The observation of massive black hole binary systems is one of the main science objectives of the Laser Interferometer Space Antenna (LISA). The instrument's design requirements have recently been revised: they set a requirement at $0.1\,\mathrm{mHz}$, with no additional explicit requirements at lower frequencies. This has implications for observations of the short-lived signals produced by the coalescence of massive and high-redshift binaries. Here we consider the most pessimistic scenario: the (unlikely) case in which LISA has no sensitivity below $0.1\,\mathrm{mHz}$. We show that the presence of higher multipoles (beyond the dominant $\ell = |m| = 2$ mode) in the gravitational radiation from these systems, which will be detectable with a total signal-to-noise ratio $\sim 10^3$, allows LISA to retain the capability to accurately measure the physical parameters, the redshift, and to constrain the sky location. To illustrate this point, we consider a few select binaries in a total (redshifted) mass range of $4 \times10^6 - 4 \times 10^7\,M_\odot$ whose ($\ell = |m| = 2$) gravitational-wave signals last between $\approx 12$ hours and $\approx 20$ days in band. We model the emitted gravitational radiation using the highly accurate (spin-aligned) waveform approximant IMRPhenomXHM and carry out a fully coherent Bayesian analysis on the LISA noise-orthogonal time-delay-interferometry channels.

The large-scale magnetic structure of interplanetary coronal mass ejections (ICMEs) has been shown to cause decreases in the galactic cosmic ray (GCR) flux measured in situ by spacecraft, known as Forbush decreases (Fds). We use measurements of the GCR count rate obtained by MESSENGER during its orbital phase around Mercury to identify such Fds related to the passage of ICMEs and characterize their structure. Of the 42 ICMEs with corresponding high-quality GCR data, 79% are associated with a Fd. Thus a total of 33 ICME-related Fds were identified, 24 of which (73%) have a two-step structure. We use a superposed epoch analysis to build an average Fd profile at MESSENGER and find that despite the variability of individual events, a two-step structure is produced and is directly linked with the magnetic boundaries of the ICME. By using results from previous studies at Earth and Mars, we also address whether two-step Fds are more commonly observed closer to the Sun; we found that although likely, this is not conclusive when comparing to the wide range of results of previous studies conducted at Earth. Finally, we find that the percentage decrease in GCR flux of the Fd is greater at MESSENGER on average than at Earth and Mars, decreasing with increasing heliocentric distance. The relationship between the percentage decrease and maximum hourly decrease is also in agreement with previous studies, and follows trends relating to the expansion of ICMEs as they propagate through the heliosphere.

We explore a model of dark matter (DM) that can explain the reported discrepancy in the muon anomalous magnetic moment and predict a large electric dipole moment (EDM) of the muon. The model contains a DM fermion and new scalars whose exclusive interactions with the muon radiatively generate the observed muon mass. Constraints from DM direct and indirect detection experiments as well as collider searches are safely evaded. The model parameter space that gives the observed DM abundance and explains the muon $g-2$ anomaly leads to the muon EDM of $d_{\mu} \simeq (4$-$5) \times 10^{-22} \, e \, {\rm cm}$ that can be probed by the projected PSI muEDM experiment. Another viable parameter space even achieves $d_{\mu} = \mathcal{O}(10^{-21}) \, e \, {\rm cm}$ reachable by the ongoing Fermilab Muon $g-2$ experiment and the future J-PARC Muon $g-2$/EDM experiment.

Motivated by cosmological models of the early universe we analyse the dynamics of the Einstein equations with a minimally coupled scalar field with monomial potentials $V(\phi)=\frac{(\lambda\phi)^{2n}}{2n}$, $\lambda>0$, $n\in\mathbb{N}$, interacting with a perfect fluid with linear equation of state $p_\mathrm{pf}=(\gamma_\mathrm{pf}-1)\rho_\mathrm{pf}$, $\gamma_\mathrm{pf}\in(0,2)$, in flat Robertson-Walker spacetimes. The interaction is a friction-like term of the form $\Gamma(\phi)=\mu \phi^{2p}$, $\mu>0$, $p\in\mathbb{N}\cup\{0\}$. The analysis relies on the introduction of a new regular 3-dimensional dynamical systems' formulation of the Einstein equations on a compact state space, and the use of dynamical systems' tools such as quasi-homogeneous blow-ups and averaging methods involving a time-dependent perturbation parameter. We find a bifurcation at $p=n/2$ due to the influence of the interaction term. In general, this term has more impact on the future (past) asymptotics for $p<n/2$ ($p>n/2$). For $p<n/2$ we find a complexity of possible future attractors, which depends on whether $p=(n-1)/2$ or $p<(n-1)/2$. In the first case the future dynamics is governed by Li\'enard systems. On the other hand when $p=(n-2)/2$ the generic future attractor consists of new solutions previously unknown in the literature which can drive future acceleration whereas the case $p<(n-2)/2$ has a generic future attractor de-Sitter solution. For $p=n/2$ the future asymptotics can be either fluid dominated or have an oscillatory behaviour where neither the fluid nor the scalar field dominates. For $p>n/2$ the future asymptotics is similar to the case with no interaction. Finally, we show that irrespective of the parameters, an inflationary quasi-de-Sitter solution always exists towards the past, and therefore the cases with $p\leq(n-2)/2$ may provide new cosmological models of quintessential inflation.

We reproduce the rotation curve of the Andromeda galaxy (M31) by taking into account its bulge, disk, and halo components, considering the last one to contain the major part of dark matter mass. Hence, our prescription is to split the galactic bulge into two components, namely, the inner and main bulges, respectively. Both bulges are thus modeled by exponential density profiles since we underline that the widely accepted de Vaucouleurs law fails to reproduce the whole galactic bulge rotation curve. In addition, we adopt various well-known phenomenological dark matter profiles to estimate the dark matter mass in the halo region. Moreover, we apply the least-squares fitting method to determine from the rotation curve the model free parameters, namely, the characteristic (central) density, scale radius, and consequently the total mass. To do so, we perform Markov chain Monte Carlo statistical analyses based on the Metropolis algorithm, maximizing our likelihoods adopting velocity and radii data points of the rotation curves. We do not fit separately the components for bulges, disk and halo, but we perform an overall fit including all the components and employing all the data points. Thus, we critically analyze our corresponding findings and, in particular, we employ the Bayesian Information Criterion to assess the most accredited model to describe M31 dark matter dynamics.

It is known that magnetic fields exist near black holes and photons can go around the black holes due to strong gravity. Utilizing these facts, we can probe hypothetical pseudoscalar particles, so-called axions. In fact, photons can be converted into axions when they propagate in a magnetic field. The conversion of such photons into axions leads to a dimming of the photon ring around the black hole shadow. We show that the photon ring dimming can occur efficiently for supermassive black holes. Remarkably, it turns out that the maximal dimming rate of the photon ring is 25%. In the case of M87$^*$, the dimming could be around 10% in the X-ray and gamma-ray bands. The frequency band and the magnitude of the dimming depend on the axion-photon coupling and axion mass. Hence, the distorted spectrum of the photon ring provides a novel tool for detecting axions.

Pulsar Timing constraints on scalar-tensor theories with conformal and disformal couplings to matter are discussed. Reducing the dynamics to the motion in the centre of mass frame and using the mean anomaly parametrisation, we find the first post-Newtonian corrections induced by the conformal and disformal interactions in the form of a generalized quasi-Keplerian solution. We also derive the radiation reaction force due to scalar radiation and the corresponding Post-Keplerian Parameters (PKP). We use different pulsar time of arrival (TOA) data sets to probe the scalar corrections to the PKP. In particular, we focus on systems with large orbital frequencies as the contributions to the PKP terms induced by the disformal coupling are sensitive to higher frequencies. We find that the most constraining pulsar timing events are PSR B1913+16 and the double pulsar PSR J0737-3039A/B, being stronger than the Cassini bound on the conformal coupling obtained from the Shapiro effect in the solar system. The combined constraints using other pulsar events give an upper bound on the conformal coupling $\beta^2 < 2.3 \cdot 10^{-5}$ and a lower bound on the disformal coupling scale of $\Lambda \sim 1 \ {\rm MeV}$ which is comparable to the Cassini bound and to the GW-170817 constraints respectively. Future measurements for pulsar timing with black hole companions are also discussed.