Papers for Thursday, Dec 02 2021

We investigate the stochastic properties of typical red galaxy samples in a controlled numerical environment. We use Halo Occupation Distribution (HOD) modelling to create mock realizations of three separate bright red galaxy samples consistent with datasets used for clustering and lensing analyses in modern galaxy surveys. Second-order Hybrid Effective Field Theory (HEFT) is used as a field-level forward model to describe the full statistical distribution of these tracer samples, and their stochastic power spectra are directly measured and compared to the Poisson shot-noise prediction. While all of the galaxy samples we consider are hosted within haloes with sub-Poisson stochasticity, we observe that the galaxy samples themselves possess stochasticities that range from sub-Poisson to super-Poisson, in agreement with predictions from the halo model. As an application of our methodology, we place priors on the expected degree of non-Poisson stochasticity in cosmological analyses using such samples. We expect these priors will be useful in reducing the complexity of the full parameter space for future analyses using second-order Lagrangian bias models. More generally, the techniques outlined here present the first application of hybrid EFT methods to characterize models of the galaxy--halo connection at the field level, revealing new connections between once-disparate modelling frameworks.

We use the self-consistent stellar populations in the Binary Population A Spectral Synthesis (BPASS) models to assess whether NGC1850-BH1 is a black hole. Using search criteria based on reported physical properties in Saracino et al. (2021) and El-Badry & Burdge (2021) we purposefully search for suitable systems with a black hole (or compact object) companion: we do not find any. Good matches to the observations are found in models where the bright component is a stripped star and the companion is natively (meaning we did not impose this in our search) 3 to 4 magnitudes fainter than the primary in optical bands. This alone can explain the lack of detection of the companion in the MUSE spectra without the need to invoke rapid rotation, although the conservative mass transfer exhibited by these particular models is likely to lead to rapidly rotating companions which could further smear their spectroscopic signatures. We advise that future claims of unseen black holes in binary systems would benefit from exploring detailed binary evolution models of stellar populations as a sanity check.

We present new HI interferometric observations of the gas-rich ultra-diffuse galaxy AGC 114905, which previous work, based on low-resolution data, identified as an outlier of the baryonic Tully-Fisher relation. The new observations, at a spatial resolution $\sim 2.5$ times higher than before, reveal a regular HI disc rotating at about 23 km/s. Our kinematic parameters, recovered with a robust 3D kinematic modelling fitting technique, show that the flat part of the rotation curve is reached. Intriguingly, the rotation curve can be explained almost entirely by the baryonic mass distribution alone. We show that a standard cold dark matter halo that follows the concentration-halo mass relation fails to reproduce the amplitude of the rotation curve by a large margin. Only a halo with an extremely (and arguably unfeasible) low concentration reaches agreement with the data. We also find that the rotation curve of AGC 114905 deviates strongly from the predictions of Modified Newtonian dynamics. The inclination of the galaxy, which is measured independently from our modelling, remains the largest uncertainty in our analysis, but the associated errors are not large enough to reconcile the galaxy with the expectations of cold dark matter or Modified Newtonian dynamics.

We present spectroscopic analysis of the luminous X-ray source Melnick 33Na (Mk 33Na, HSH95 16) in the LMC 30 Doradus region (Tarantula Nebula), utilising new time-series VLT/UVES spectroscopy. We confirm Mk 33Na as a double-lined O-type spectroscopic binary with a mass ratio $q = 0.63 \pm 0.02$, $e = 0.33 \pm 0.01$ and orbital period of $18.3 \pm 0.1$ days, supporting the favoured period from X-ray observations obtained via the Tarantula -- Revealed by X-rays (T-ReX) survey. Disentangled spectra of each component provide spectral types of OC2.5 If* and O4 V for the primary and secondary respectively - unusually for an O supergiant the primary exhibits strong CIV 4658 emission and weak NV 4603-20, justifying the OC classification. Spectroscopic analysis favours extreme physical properties for the primary ($T_{\rm eff} = 50$ kK, $\log L/L_{\odot} = 6.15$) with system components of $M_{1} = 83 \pm 19 M_{\odot}$ and $M_{2} = 48 \pm 11 M_{\odot}$ obtained from evolutionary models, which can be reconciled with results from our orbital analysis (e.g. $M_{1} \sin^3 i = 20.0 \pm 1.2 M_{\odot}$) if the system inclination is $\sim 38^{\circ}$ and it has an age of 0.9 to 1.6 Myr. This establishes Mk 33Na as one of the highest mass binary systems in the LMC, alongside other X-ray luminous early-type binaries Mk34 (WN5h+WN5h), R144 (WN5/6h+WN6/7h) and especially R139 (O6.5\,Iafc+O6\,Iaf).

Radio relics are diffuse synchrotron sources that illuminate shock waves in the intracluster medium. In recent years, radio telescopes have provided detailed observations about relics. Consequently, cosmological simulations of radio relics need to provide a similar amount of detail. In this methodological work, we include information on adiabatic compression and expansion, which have been neglected in the past in the modelling of relics. In a cosmological simulation of a merging galaxy cluster, we follow the energy spectra of shock accelerated cosmic-ray electrons using Lagrangian tracer particles. On board of each tracer particle, we compute the temporal evolution of the energy spectrum under the influence of synchrotron radiation, inverse Compton scattering, and adiabatic compression and expansion. Exploratory tests show that the total radio power and, hence, the integrated radio spectrum are not sensitive to the adiabatic processes. This is attributed to small changes in the compression ratio over time.

In general relativity (GR), the internal dynamics of a self-gravitating system under free-fall in an external gravitational field should not depend on the external field strength. Recent work has claimed a statistical detection of an `external field effect' (EFE) using galaxy rotation curve data. We show that large uncertainties in rotation curve analyses and inaccuracies in published simulation-based external field estimates compromise the significance of the claimed EFE detection. We further show analytically that a qualitatively similar statistical signal is, in fact, expected in a $\Lambda$-cold dark matter ($\Lambda$CDM) universe without any violation of the strong equivalence principle. Rather, such a signal arises simply because of the inherent correlations between galaxy clustering strength and intrinsic galaxy properties. We explicitly demonstrate the effect in a baryonified mock catalog of a $\Lambda$CDM universe. Although the detection of an EFE-like signal is not, by itself, evidence for physics beyond GR, our work shows that the $\textit{sign}$ of the EFE-like correlation between the external field strength and the shape of the radial acceleration relation can be used to probe new physics: e.g., in MOND, the predicted sign is opposite to that in our $\Lambda$CDM mocks.

The nebular recombination line H$\alpha$ is widely used as a star-formation rate (SFR) indicator in the local and high-redshift Universe. We present a detailed H$\alpha$ radiative transfer study of high-resolution isolated Milky-Way and Large Magellanic Cloud simulations that include radiative transfer, non-equilibrium thermochemistry, and dust evolution. We focus on the spatial morphology and temporal variability of the H$\alpha$ emission, and its connection to the underlying gas and star formation properties. The H$\alpha$ and H$\beta$ radial and vertical surface brightness profiles are in excellent agreement with observations of nearby galaxies. We find that the fraction of H$\alpha$ emission from collisional excitation amounts to $f_{\rm col}\sim5-10\%$, only weakly dependent on radius and vertical height, and that scattering boosts the H$\alpha$ luminosity by $\sim40\%$. The dust correction via the Balmer decrement works well (intrinsic H$\alpha$ emission recoverable within $25\%$), though the dust attenuation law depends on the amount of attenuation itself both on spatially resolved and integrated scales. Important for the understanding of the H$\alpha$-SFR connection is the dust and helium absorption of ionizing radiation (Lyman continuum [LyC] photons), which are about $f_{\rm abs}\approx28\%$ and $f_{\rm He}\approx9\%$, respectively. Together with an escape fraction of $f_{\rm esc}\approx6\%$, this reduces the available budget for hydrogen line emission by nearly half ($f_{\rm H}\approx57\%$). We discuss the impact of the diffuse ionized gas, showing - among other things - that the extraplanar H$\alpha$ emission is powered by LyC photons escaping the disc. Future applications of this framework to cosmological (zoom-in) simulations will assist in the interpretation of spectroscopy of high-redshift galaxies with the upcoming James Webb Space Telescope.

We present an analysis of a newly discovered 2+1+1 quadruple system with TESS containing an unresolved eclipsing binary (EB) as part of TIC 121088960 and a close neighbor TIC 121088959. The EB consists of two very low-mass M dwarfs in a highly-eccentric ($e$ = 0.709) short-period ($P$ = 3.04358 d) orbit. Given the large pixel size of TESS and the small separation (3.9$"$) between TIC 121088959 and TIC 121088960, we used light centroid analysis of the difference image between in-eclipse and out-of-eclipse data to show that the EB likely resides in TIC 121088960, but contributes only $\sim$10% of its light. Radial velocity data were acquired with iSHELL at NASA's Infrared Facility and the Coud${\'e}$ spectrograph at the McDonald 2.7-m telescope. For both images, the measured RVs showed no variation over the 11-day observational baseline, and the RV difference between the two images was $8 \pm 0.3$ km s$^{-1}$. The similar distances and proper motions of the two images indicate that TIC 121088959 and TIC 121088960 are a gravitationally bound pair. Gaia's large RUWE and astrometric_excess_noise parameters for TIC 121088960, further indicate that this image is the likely host of the unresolved EB and is itself a triple star. We carried out an SED analysis and calculated stellar masses for the four stars, all of which are in the M dwarf regime: 0.19 M$_\odot$ and 0.14 M$_\odot$ for the EB stars and 0.43 M$_\odot$ and 0.39 M$_\odot$ for the brighter visible stars, respectively. Lastly, numerical simulations show that the orbital period of the inner triple is likely the range 1 to 50 years.

We present an analysis of all currently available ground-based imaging of Neptune in the mid-infrared. Dating between 2003 and 2020, the images reveal changes in Neptune's mid-infrared (~8-25 micron) emission over time. Images sensitive to stratospheric ethane (~12 micron), methane (~8 micron), and CH3D (~9 micron) display significant sub-seasonal temporal variation on regional and global scales. Comparison with hydrogen-quadrupole (~17-micron H2 S(1)) spectra suggests these changes are primarily related to stratospheric temperature changes. The stratosphere appears to have cooled between 2003 and 2010 across multiple filtered wavelengths, followed by a dramatic warming of the south pole between 2018 and 2020. Conversely, upper tropospheric temperatures appear invariant during this period, except for the south pole, which appeared warmest between 2003 and 2006. We discuss the observed variability in the context of seasonal forcing, tropospheric meteorology, and the solar cycle. Collectively, these data provide the strongest evidence to date that processes produce sub-seasonal variation on both global and regional scales in Neptune's stratosphere.

To investigate the origins of the warm absorbers in active galactic nuclei (AGNs), we study the ionization-state structure of the radiation-driven fountain model in a low-mass AGN (Wada et al. 2016) and calculate the predicted X-ray spectra, utilizing the spectral synthesis code Cloudy (Ferland et al. 2017). The spectra show many absorption and emission line features originated in the outflowing ionized gas. The O VIII 0.654 keV lines are produced mainly in the polar region much closer to the SMBH than the optical narrow line regions. The absorption measure distribution of the ionization parameter ($\xi$) at a low inclination spreads over 4 orders of magnitude in $\xi$, indicating multi-phase ionization structure of the outflow, as actually observed in many type-1 AGNs. We compare our simulated spectra with the high energy-resolution spectrum of the narrow line Seyfert 1 galaxy, NGC 4051. The model reproduces slowly outflowing (a few hundreds km s$^{-1}$) warm absorbers. However, the faster components with a few thousands km s$^{-1}$ observed in NGC 4051 are not reproduced. The simulation also underproduces the intensity and width of the O VIII 0.654 keV line. These results suggest that the ionized gas launched from sub-parsec or smaller regions inside the torus, which are not included in the current fountain model, must be important ingredients of the warm absorbers with a few thousands km s$^{-1}$. The model also consistently explains the Chandra/HETG spectrum of the Seyfert 2 galaxy, the Circinus galaxy.

We reassess the viability of a cosmological model including a fourth additional sterile neutrino species that self-interacts through a new pseudoscalar degree of freedom. To that end, we perform a series of extensive analyses fitting various combinations of cosmic microwave background (CMB) data from Planck, the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), both alone and in combination with Baryon Acoustic Oscillation (BAO) and Supernova Ia (SnIa) observations. We show that the scenario under study, although capable to resolve the Hubble tension without worsening the so-called $S_8$ tension about the growth of structures, is severely constrained by high-multipole polarization data from both Planck and SPT. Intriguingly, when trading Planck TE-EE data for those from ACT, we find a $\gtrsim 3 \sigma$ preference for a non-zero sterile neutrino mass, $m_s=3.6^{+1.1}_{-0.6}$ eV (68% C.L.), compatible with the range suggested by longstanding short-baseline (SBL) anomalies in neutrino oscillation experiments. The preference is mostly driven by ACT favouring a higher value for the primordial spectral index $n_s$ with respect to Planck and SPT. The pseudoscalar model appears indeed to provide a better fit to ACT data with respect to $\Lambda$CDM ($\Delta\chi^2 \simeq -5$). In particular, we show that the mild tension between Planck and ACT is due to the different pattern in the TE and EE power spectra on multipoles between $350 \lesssim \ell \lesssim 1000$. We also check the impact of marginalizing over the gravitational lensing information in Planck data, showing that the model does not solve the CMB lensing anomaly. Future work including higher precision data from current and upcoming CMB ground-based experiments will be crucial to test these results.

Optical secondary eclipse measurements made by \emph{Kepler} reveal a diverse set of geometric albedos for hot Jupiters with equilibrium temperatures between $1550-1700$ K. The presence or absence of high altitude condensates, such as Mg$_2$SiO$_4$, Fe, Al$_2$O$_3$, and TiO$_2$, can significantly alter optical albedos, but these clouds are expected to be confined to localized regions in the atmospheres of these tidally locked planets. Here, we present 3D general circulation models and corresponding cloud and albedo maps for six hot Jupiters with measured optical albedos in this temperature range. We find that the observed optical albedos of K2-31b and K2-107b are best matched by either cloud free models or models with relatively compact cloud layers, while Kepler-8b and Kepler-17b's optical albedos can be matched by moderately extended ($f_{sed}$ = 0.1) parametric cloud models. HATS-11b has a high optical albedo, corresponding to models with bright Mg$_2$SiO$_4$ clouds extending to very low pressures ($f_{sed}$ = 0.03). We are unable to reproduce Kepler-7b's high albedo, as our models predict that the dayside will be dominated by dark Al$_2$O$_3$ clouds at most longitudes. We compare our parametric cloud model with a two-zone microphysical cloud model (\texttt{CARMA}). We find that even after accounting for the 3D thermal structure, no single cloud model can explain the full range of observed albedos within the sample. We conclude that a better knowledge of the vertical mixing profiles, cloud radiative feedback, cloud condensate properties, and atmospheric metallicities is needed in order to explain the unexpected diversity of albedos in this temperature range.

In spite of substantial advancements in simulating planet formation, the planet Mercury's diminutive mass, isolated orbit, and the absence of planets with shorter orbital periods in the solar system continue to befuddle numerical accretion models. Recent studies have shown that, if massive embryos (or even giant planet cores) formed early in the innermost parts of the Sun's gaseous disk, they would have migrated outward. This migration may have reshaped the surface density profile of terrestrial planet-forming material and generated conditions favorable to the formation of Mercury-like planets. Here, we continue to develop this model with an updated suite of numerical simulations. We favor a scenario where Earth and Venus' progenitor nuclei form closer to the Sun and subsequently sculpt the Mercury-forming region by migrating towards their modern orbits. This rapid formation of ~0.5 Earth-mass cores at ~0.1-0.5 au is consistent with modern high-resolution simulations of planetesimal accretion. In successful realizations, Earth and Venus accrete mostly dry, Enstatite Chondrite-like material as they migrate; thus providing a simple explanation for the masses of all four terrestrial planets, inferred isotopic differences between Earth and Mars, and Mercury's isolated orbit. Furthermore, our models predict that Venus' composition should be similar to the Earth's, and possibly derived from a larger fraction of dry material. Conversely, Mercury analogs in our simulations attain a range of final compositions.

We use 118 H$\beta$ quasar (QSO) observations in the redshift range $0.0023 \leq z \leq 0.89$ to simultaneously constrain cosmological model parameters and QSO 2-parameter radius-luminosity ($R-L$) relation parameters in six different cosmological models. We find that the $R-L$ relation parameters for these QSOs are independent of the assumed cosmology so these QSOs seem to be standardizable through the $R-L$ relation (although there is a complication that might render this untrue). Cosmological constraints obtained using these QSOs are weak, more favor currently decelerated cosmological expansion, and are $\sim 2\sigma$ inconsistent with those obtained from a joint analysis of baryon acoustic oscillation and Hubble parameter measurements. Extending the $R-L$ relation to a 3-parameter one to try to correct for the accretion rate effect does not result in a reduction of the cosmological constraints discrepancy nor does it result in the hoped-for significant reduction of the intrinsic scatter of the $R-L$ relation.

We present detailed abundance measurements for 45 globular clusters (GCs) in galaxies in (and, in one case, beyond) the Local Group. The measurements are based on new high-resolution integrated-light spectra of GCs in NGC 185, NGC 205, M31, M33, and NGC 2403, combined with reanalysis of previous observations of GCs in the Fornax dSph, WLM, NGC 147, NGC 6822, and the Milky Way. The GCs cover the range -2.8 < [Fe/H] < -0.1 and we determined abundances for Fe, Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Ni, Cu, Zn, Zr, Ba, and Eu. Corrections for non local thermodynamic equilibrium effects are included for Na, Mg, Ca, Ti, Mn, Fe, Ni, and Ba. For several of the galaxies, our measurements provide the first quantitative constraints on the detailed composition of their metal-poor stellar populations. Overall, the GCs in different galaxies exhibit remarkably uniform abundance patterns of the alpha-, iron-peak, and neutron-capture elements, with a dispersion of less than 0.1 dex in [alpha/Fe] for the full sample. There is a hint that GCs in dwarf galaxies are slightly less alpha-enhanced (by about 0.04 dex on average) than those in larger galaxies. One GC in M33 (HM33-B) resembles the most metal-rich GCs in the Fornax dSph (Fornax 4) and NGC 6822 (SC7) by having alpha-element abundances closer to scaled-solar values, possibly hinting at an accretion origin. We find that the alpha-element abundances strongly correlate with those of Na, Sc, Ni, and Zn. Several GCs with [Fe/H]<-1.5 are deficient in Mg compared to other alpha-elements. We find no GCs with strongly enhanced r-process abundances as reported for metal-poor stars in some ultra-faint dwarfs and the Magellanic Clouds. The similarity of the abundance patterns for metal-poor GCs in different environments points to similar early enrichment histories and only allow for minor variations in the initial mass function.

The luminosity function (LF) of active galactic nuclei (AGN) probes the history of supermassive black hole assembly and growth across cosmic time. To mitigate selection biases, we present a consistent analysis of the AGN LFs derived for both X-ray and mid-infrared (MIR) selected AGN in the XMM-Large Scale Structure (XMM-LSS) field. There are 4268 AGN used to construct the MIR luminosity function (IRLF) and 3427 AGN used to construct the X-ray luminosity function (XLF), providing the largest census of the AGN population out to $z=4$ in both bands with significant reduction in uncertainties. We are able for the first time to see the knee of the IRLF at $z>2$ and observe a flattening of the faint-end slope as redshift increases. The bolometric luminosity density, a proxy for the cosmic black hole accretion history, computed from our LFs shows a peak at $z\approx2.25$ consistent with recent estimates of the peak in the star formation rate density (SFRD). However, at earlier epochs, the AGN luminosity density is flatter than the SFRD. If confirmed, this result suggests that the build up of black hole mass outpaces the growth of stellar mass in high mass systems at $z\gtrsim 2.5$. This is consistent with observations of redshift $z\sim 6$ quasars which lie above the local $M-\sigma$ relationship. The luminosity density derived from the IRLF is higher than that from the XLF at all redshifts. This is consistent with the dominant role of obscured AGN activity in the cosmic growth of supermassive black holes.

Motivated by the detection of very high energy gamma-rays deep in the afterglow emission of a gamma-ray burst, we revisit predictions of the maximum energy to which electrons can be accelerated at a relativistic blast wave. Acceleration at the weakly-magnetized forward shock of a blast-wave can be limited either by the rapid damping of turbulence generated behind the shock, by the effect of a large-scale ambient magnetic field, or by radiation losses. Within the confines of a standard, single zone, synchrotron-self-Compton (SSC) model, we show that observations of GRB190829A rule out a rapid damping of the downstream turbulence. Furthermore, simultaneous fits to the X-ray and TeV gamma-ray emission of this object are not possible unless the limit on acceleration imposed by the ambient magnetic field is comparable or weaker than that imposed by radiation losses. This requires the dominant length scale of the turbulence behind the shock to be larger than that implied by particle-in-cell simulations. However, even then, Klein-Nishina effects prevent production of the hard VHE gamma-ray spectrum suggested by observations. Thus, TeV observations of GRB afterglows, though still very sparse, are already in tension with the SSC emission scenario.

For several transition disks (TDs), dark regions interpreted as shadows have been observed in scattered light imaging and are hypothesized to originate from misalignments between distinct disk regions. We aim to investigate the presence of misalignments in TDs. We study the inner disk geometries of 20 well-known transition disks with VLTI/GRAVITY observations and use complementary $^{12}$CO and $^{13}$CO molecular line data from ALMA to derive the orientation of the outer disk regions. We fit simple models to the GRAVITY data to derive the inner disks inclination and position angles. The outer disk geometries were derived from Keplerian fits to the ALMA velocity maps and compared to the inner disk constraints. We also predicted the locations of shadows for significantly misaligned systems. Our analysis reveals six disks to exhibit significant misalignments between their inner and outer disks. The predicted shadow positions agree well with the scattered light images of HD100453 and HD142527, and we find supporting evidence for a shadow in the disk around CQ Tau. In the other three targets for which we infer significantly misaligned disks, V1247 Ori, V1366 Ori, and RY Lup, we do not see any evident sign of shadows in the scattered light images. The scattered light shadows observed in DoAr44, HD135344B, and HD139614 are consistent with our observations, yet the underlying morphology is likely too complex to be described by our models and the accuracy achieved by our observations. Whereas we can derive precise constraints on the potential shadow positions for well-resolved inner disks around HAeBe stars, the statistical uncertainties for the marginally resolved inner disks around the TTS of our sample make it difficult to extract conclusive constraints for the presence of shadows in these systems.

We present a new model to compute the luminosity of emission lines in star forming galaxies and apply this in the semi-analytical galaxy formation code GALFORM. The model combines a pre-computed grid of HII region models with an empirical determination of how the properties of HII regions depend on the macroscopic properties of galaxies based on observations of local galaxies. The new model gives a very good reproduction of the locus of star-forming galaxies on standard line ratio diagnostic diagrams. The new model shows evolution in the locus of star forming galaxies with redshift on this line ratio diagram, with a good match to the observed line ratios at $z=1.6$. The model galaxies at high redshift have gas densities and ionisation parameters that are predicted to be $\approx 2-3$ times higher than in local star forming galaxies, which is partly driven by the changing selection with redshift to mimic the observational selection. Our results suggest that the observed evolution in emission line ratios requires other HII region properties to evolve with redshift, such as the gas density, and cannot be reproduced by HII model grids that only allow the gas metallicity and ionisation parameter to vary.

In this work, we perform a first study of basic invariant sets of the spatial Hill's four-body problem, where we have used both analytical and numerical approaches. This system depends on a mass parameter mu in such a way that the classical Hill's problem is recovered when mu = 0. Regarding the numerical work, we perform a numerical continuation, for the Jacobi constant C and several values of the mass parameter mu by applying a classical predictor-corrector method, together with a high-order Taylor method considering variable step and order and automatic differentiation techniques, to specific boundary value problems related with the reversing symmetries of the system. The solution of these boundary value problems defines initial conditions of symmetric periodic orbits. Some of the results were obtained departing from periodic orbits within Hill's three-body problem. The numerical explorations reveal that a second distant disturbing body has a relevant effect on the stability of the orbits and bifurcations among these families. We have also found some new families of periodic orbits that do not exist in the classical Hill's three-body problem; these families have some desirable properties from a practical point of view.

The initial reports of the presence of phosphine in the cloud decks of Venus has led to the suggestion that volcanism was the source of phosphine, through volcanic phosphides ejected into the clouds. Here we examine the idea that mantle plume volcanism, bringing material from the deep mantle to the surface, could generate observed amounts of phosphine through interaction of explosively erupted phosphide with sulfuric acid clouds. Direct eruption of deep mantle phosphide is unphysical, but shallower material could contain traces of phosphide, and could be erupted to the surface. Explosive eruption that efficiently transported material to the clouds would require ocean:magma interactions or subduction of hydrated oceanic crust, neither of which occur on modern Venus. The transport of erupted material to altitudes coinciding with the observations of phosphine is consequently very inefficient. Using the model proposed by Truong and Lunine as a base case, we estimate that an eruption volume of at least 21,600 km3/year would be required to explain the presence of 1 ppb phosphine in the clouds. This is greater than any historical terrestrial eruption rate, and would have several detectable consequences for remote and in situ observations to confirm. More realistic lithospheric chemistry or atmospheric photochemistry require even more volcanism.

The upcoming Laser Interferometer Space Antenna (LISA) will detect a large gravitational-wave foreground of Galactic white dwarf binaries. These sources are exceptional for their probable detection at electromagnetic wavelengths, some long before LISA flies. Studies in both gravitational and electromagnetic waves will yield strong constraints on system parameters not achievable through measurements of one messenger alone. In this work, we present a Bayesian inference pipeline and simulation suite in which we study potential constraints on binaries in a variety of configurations. We show how using LISA detections and parameter estimation can significantly improve constraints on system parameters when used as a prior for the electromagnetic analyses. We also provide rules of thumb for how current measurements will benefit from LISA measurements in the future.

Detailed chemical analyses of M dwarfs are scarce but necessary to constrain the formation environment and internal structure of planets being found around them. We present elemental abundances of 13 M dwarfs (2900 < Teff < 3500 K) observed in the Subaru/IRD planet search project. They are mid-to-late M dwarfs whose abundance of individual elements has not been well studied. We use the high-resolution (~70,000) near-infrared (970-1750 nm) spectra to measure the abundances of Na, Mg, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Sr by the line-by-line analysis based on model atmospheres, with typical errors ranging from 0.2 dex for [Fe/H] to 0.3-0.4 dex for other [X/H]. We measure radial velocities from the spectra and combine them with Gaia astrometry to calculate the Galactocentric space velocities UVW. The resulting [Fe/H] values agree with previous estimates based on medium-resolution K-band spectroscopy, showing a wide distribution of metallicity (-0.6 < [Fe/H] < +0.4). The abundance ratios of individual elements [X/Fe] are generally aligned with the solar values in all targets. While the [X/Fe] distributions are comparable to those of nearby FGK stars, most of which belong to the thin disk population, the most metal-poor object, GJ 699, could be a thick disk star. The UVW velocities also support this. The results raise the prospect that near-infrared spectra of M dwarfs obtained in the planet search projects can be used to grasp the trend of elemental abundances and Galactic stellar population of nearby M dwarfs.

Evolutionary algorithms are a type of artificial intelligence that utilize principles of evolution to efficiently determine solutions to defined problems. These algorithms are particularly powerful at finding solutions that are too complex to solve with traditional techniques and at improving solutions found with simplified methods. The GENETIS collaboration is developing genetic algorithms to design antennas that are more sensitive to ultra high energy neutrino induced radio pulses than current detectors. Improving antenna sensitivity is critical because UHE neutrinos are rare and require massive detector volumes with stations dispersed over hundreds of km squared. The GENETIS algorithm evolves antenna designs using simulated neutrino sensitivity as a measure of fitness by integrating with XFdtd, a finite difference time domain modeling program, and with simulations of neutrino experiments. The best antennas will then be deployed in ice for initial testing. The genetic algorithm's aim is to create antennas that improve on the designs used in the existing ARA experiment by more than a factor of 2 in neutrino sensitivities. This research could improve antenna sensitivities in future experiments and thus accelerate the discovery of UHE neutrinos. This is the first time that antennas have been designed using genetic algorithms with a fitness score based on a physics outcome, which will motivate the continued use of genetic algorithm designed instrumentation in astrophysics and beyond. This proceeding will report on advancements to the algorithm, steps taken to improve the genetic algorithm performance, the latest results from our evolutions, and the manufacturing road map.

We present results from our analysis of the Hydra I cluster observed in neutral atomic hydrogen (HI) as part of the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). These WALLABY observations cover a 60-square-degree field of view with uniform sensitivity and a spatial resolution of 30 arcsec. We use these wide-field observations to investigate the effect of galaxy environment on HI gas removal and star formation quenching by comparing the properties of cluster, infall and field galaxies extending up to $\sim5R_{200}$ from the cluster centre. We find a sharp decrease in the HI-detected fraction of infalling galaxies at a projected distance of $\sim1.5R_{200}$ from the cluster centre from $\sim0.85\%$ to $\sim0.35\%$. We see evidence for the environment removing gas from the outskirts of HI-detected cluster and infall galaxies through the decrease in the HI to $r$-band optical disc diameter ratio. These galaxies lie on the star forming main sequence, indicating that gas removal is not yet affecting the inner star-forming discs and is limited to the galaxy outskirts. Although we do not detect galaxies undergoing galaxy-wide quenching, we do observe a reduction in recent star formation in the outer disc of cluster galaxies, which is likely due to the smaller gas reservoirs present beyond the optical radius in these galaxies. Stacking of HI non-detections with HI masses below $M_{\rm{HI}}\lesssim10^{8.4}\,\rm{M}_{\odot}$ will be required to probe the HI of galaxies undergoing quenching at distances $\gtrsim60$ Mpc with WALLABY.

In this paper, we aim at using the DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), a future Japanese space gravitational-wave antenna sensitive to frequency range between LISA and ground-based detectors, to provide gravitational-wave constraints on the cosmic curvature at $z\sim 5$. In the framework of the well-known distance sum rule, the perfect redshift coverage of the standard sirens observed by DECIGO, compared with lensing observations including the source and lens from LSST, makes such cosmological-model-independent test more natural and general. Focusing on three kinds of spherically symmetric mass distributions for the lensing galaxies, we find that the cosmic curvature is expected to be constrained with the precision of $\Delta \Omega_K \sim 10^{-2}$ in the early universe ($z\sim5.0$), improving the sensitivity of ET constraints by about a factor of 10. However, in order to investigate this further, the mass density profiles of early-type galaxies should be properly taken into account. Specially, our analysis demonstrates the strong degeneracy between the spatial curvature and the lens parameters, especially the redshift evolution of power-law lens index parameter. When the extended power law mass density profile is assumed, the weakest constraint on the cosmic curvature can be obtained. Whereas, the addition of DECIGO to the combination of LSST+DECIGO does improve the constraint on the luminosity density slope and the anisotropy of the stellar velocity dispersion significantly. Therefore, our paper highlights the benefits of synergies between DECIGO and LSST in constraining new physics beyond the standard model, which could manifest itself through accurate determination of the cosmic curvature.

Gravitational waves (GW) can be employed as standard sirens that will soon measure the Hubble constant with sufficient precision to weigh in on the $\sim 5\sigma$ Hubble tension. Most GW sources will have no identified electromagnetic counterpart, leading to uncertainty in the redshift of the source, and in turn a degeneracy between host galaxy distance, redshift, and $H_0$. In the case where no electromagnetic counterparts are identified, it has been proposed that a statistical canvassing of candidate GW hosts, found in a large galaxy survey for example, can be used to accurately constrain the Hubble constant. We study and simulate this "galaxy voting" method to compute $H_0$. We find that the Hubble constant posterior is in general biased relative to the true value even when making optimistic assumptions about the statistical properties of the sample. This bias is caused by the fundamental degeneracy between redshift and $H_0$, and is effectively irreducible without accurate information about the redshift distribution from which the GW sources come.

Spectral hole burning reduces sodium laser guide star efficiency. Due to photon recoil, atoms that are initially resonant with the single-frequency laser get Doppler shifted out of resonance, which reduces the return flux. Frequency-chirped (also known as frequency-swept) continuous-wave lasers have the potential to mitigate the effect of spectral hole burning and even increase the laser guide star efficiency beyond the theoretical limit of a single-frequency laser. On-sky measurements of a frequency-chirped, single-frequency laser guide star are performed at the Roque de los Muchachos Observatory on La Palma. In the experiment, a 35-cm telescope and a fast photon counting receiver system are employed to resolve the return flux response during laser frequency sweeps gaining insights into the population dynamics of the sodium layer. At a launched laser power of 16.5 W, we find a maximum gain in return flux of 22\% compared to a fixed-frequency laser. Our results suggest a strong dependence of chirping gain on power density at the mesosphere, i.e. laser power and seeing. Maximum gains are recorded at a chirping amplitude on the order of 150 MHz and a chirping rate of 0.8 MHz $\mu$s$^{-1}$, as predicted by theory. Time-resolved measurements during the chirping period confirm our understanding of the population dynamics in the sodium layer. To our knowledge these are the first measurements of return flux enhancement for laser guide stars excited by a single frequency-chirped continuous-wave laser. For higher laser powers, the effectiveness of chirping is expected to increase, which could be highly beneficial for telescopes equipped with high-power laser guide star adaptive optics systems, also for emerging space awareness applications using laser guide stars such as satellite imaging and ground-to-space optical communications.

Many sources contribute to the diffuse gamma-ray background (DGRB), including star forming galaxies, active galactic nuclei, and cosmic ray interactions in the Milky Way. Exotic sources, such as dark matter annihilation, may also make some contribution. The photon counts-in-pixels distribution is a powerful tool for analyzing the DGRB and determining the relative contributions of different sources. However, including photon energy information in a likelihood analysis of the counts-in-pixels distribution quickly becomes computationally intractable as the number of source types and energy bins increase. Here, we apply the likelihood-free method of Approximate Bayesian Computation (ABC) to the problem. We consider a mock analysis that includes contributions from dark matter annihilation in galactic subhalos as well as astrophysical backgrounds. We show that our results using ABC are consistent with the exact likelihood when energy information is discarded, and that significantly tighter parameter constraints can be obtained with ABC when energy information is included. ABC presents a powerful tool for analyzing the DGRB and understanding its varied origins.

We investigate the effects of winds on the observational properties of Type Ib and Ic supernova (SN Ib/Ic) progenitors using spectral models constructed with the non-LTE stellar atmospheric code CMFGEN. We consider SN Ib/Ic progenitor models of the final mass range of 2.16 -- 9.09~$M_\odot$ having different surface temperatures and chemical compositions, and calculate the resulting spectra for various wind mass-loss rates and wind terminal velocities. We find that the progenitors having an optically thick wind would become brighter in the optical for a higher mass-loss rate (or a lower wind terminal velocity), because of the formation of the photosphere in the extended wind matter and the contribution from free-free and line emissions from the wind. As a result, for the standard Wolf-Rayet wind mass-loss rate, helium-deficient compact SN Ic progenitors would be brighter in the optical by $\sim$3 mag compared to the case without the wind effects. We also find that the color dependence on the photospheric temperature is non-monotonic because of the wind effects. Our results imply that inferring the progenitor mass, bolometric luminosity and effective temperature from the optical observation using the standard stellar evolution model prediction can be misleading. By comparing our fiducial model predictions with the detection limits of the previous SN Ib/Ic progenitor searches, we conclude that a deep search with an optical absolute magnitude larger than $\sim -4$ is needed to directly identify most of the ordinary SN Ib/Ic progenitors. We discuss implications of our results for the observed SN Ib/Ic progenitor candidates for iPTF13bvn, SN 2019vyr and SN 2017ein.

M82 X-2 is the first pulsating ultraluminous X-ray source (PULX) discovered. The luminosity of these extreme pulsars, if isotropic, implies an extreme mass transfer rate. An alternative is to assume a much lower mass transfer rate, but an apparent luminosity boosted by geometrical beaming. Only an independent measurement of the mass transfer can help discriminate between these two scenarios. In this Paper, we follow the orbit of the neutron star for seven years, measure the decay of the orbit, and demonstrate that this orbital decay is driven by extreme mass transfer of more than 150 times the mass transfer limit set by the Eddington luminosity. This measurement shows that the mass available to the accretor is more than enough to justify its luminosity, with no need for beaming. This also strongly favors models where the accretor is a highly-magnetized neutron star.

Be/$\gamma$-ray binaries comprise a confirmed or presumptive pulsar orbiting a Be star and emit luminous $\gamma$-rays. Non-thermal emissions are thought to arise from synchrotron radiation and inverse-Compton (IC) scattering in the shock where the pulsar wind is terminated by the stellar outflow. We study wind interactions and shock radiations from such systems and show that the bimodal structures observed in keV/TeV light curves are caused by enhanced synchrotron radiation and IC scattering during disc passages. We use a simple radiation model to reproduce orbital modulations of keV X-ray and TeV $\gamma$-ray flux and compare with two confirmed pulsar/Be star binaries (i.e. PSR B1259-63/LS 2883 and PSR J2032+4127/MT91 213), and two candidates (i.e. HESS J0632+057 and LS I +61$^{\circ}$303). We find that the keV/TeV light curves of the former two binaries can be well explained by the inclined disc model, while modelling the modulated emissions of the latter two sources remains challenging with current orbital solutions. Therefore, we propose alternative orbital geometries for HESS J0632+057 and LS I +61$^{\circ}$303. We estimate the positions and inclination angles of Be discs by fitting correlated keV/TeV light curves. Our results could be beneficial for future measurements of orbital parameters and searches for radio pulsations from presumed pulsars.

Models of highly inhomogeneous baryosynthesis of the baryonic asymmetric Universe allow for the existence of macroscopic domains of antimatter, which could evolve in a globular cluster of antimatter stars in our Galaxy. We assume the symmetry of the evolution of a globular cluster of stars and antistars based on the symmetry of the properties of matter and antimatter. Such object can be a source of a fraction of antihelium nuclei in galactic cosmic rays. It makes possible to predict the expected fluxes of cosmic antinuclei with use of known properties of matter star globular clusters We have estimated the lower cutoff energy for the penetration of antinuclei from the antimatter globular cluster, situated in halo, into the galactic disk based on the simulation of particle motion in the large-scale structure of magnetic fields in the Galaxy. We have estimated the magnitude of the magnetic cutoff for the globular cluster M4.

The latest evolutionary phases of low- and intermediate mass stars are characterized by complex physical processes like turbulence, convection, stellar pulsations, magnetic fields, condensation of solid particles, and the formation of massive outflows that inject freshly produced heavy elements and dust particles into the interstellar medium. We use the Northern Extended Millimeter Array (NOEMA) to obtain spatially and spectrally resolved observations of the semi-regular Asymptotic Giant Branch star RS Cancri to shed light on the morpho-kinematic structure of its inner, wind forming environment by applying detailed 3-D reconstruction modeling and LTE radiative transfer calculations. We detect 32 lines of 13 molecules and isotopologs (CO, SiO, SO, SO$_2$, H$_2$O, HCN, PN), including several transitions from vibrationally excited states. HCN, H$^{13}$CN, millimeter vibrationally excited H$_2$O, SO, $^{34}$SO, SO$_2$, and PN are detected for the first time in RS Cnc. Evidence for rotation is seen in HCN, SO, SO$_2$, and SiO(v=1). From CO and SiO channel maps, we find an inner, equatorial density enhancement, and a bipolar outflow structure with a mass loss rate of $1 \times 10^{-7}M_\odot{\rm yr}^{-1}$ for the equatorial region and of $2 \times 10^{-7}M_\odot{\rm yr}^{-1}$ for the polar outflows. The $^{12}$CO/$^{13}$CO ratio is measured to be $\sim20$ on average, $24\pm2$ in the polar outflows and $19\pm3$ in the equatorial region. We do not find direct evidence of a companion that might explain this kind of kinematic structure, and explore the possibility that a magnetic field might be the cause of it. The innermost molecular gas is influenced by stellar pulsation and possibly by convective cells that leave their imprint on broad wings of certain molecular lines, such as SiO and SO.

We present MUSE deep integral-field unit spectroscopy of three planetary nebulae(PNe) with high abundance discrepancy factors (ADF > 20): NGC 6778, M 1-42 and Hf 2-2. We have constructed flux maps for more than 40 emission lines, and use them to build extinction, electron temperature (T$_e$), electron density (n$_e$), and ionic abundances maps of a number of ionic species. The effects of the contribution of recombination to the auroral [N II] and [O II] lines on T$_e$ and the abundance maps of low-ionization species are evaluated using recombination diagnostics. As a result, low T$_e$ values and a downward gradient of T$_e$ are found toward the inner zones of each PN. Spatially, this nearly coincides with the increase of abundances of heavy elements measured using recombination lines in the inner regions of PNe, and strongly supports the presence of two distinct gas phases: a cold and metal-rich and a warm one with "normal" metal content. We have simultaneously constructed, for the first time, the ADF maps of O$^+$ and O$^{2+}$ and found that they centrally peak for all three PNe under study. We show that the main issue when trying to compute realistic abundances from either ORLs or CELs is to estimate the relative contribution of each gas component to the H I emission, and we present a method to evaluate it. It is also found that, for the studied high-ADF PNe, the amount of oxygen in the cold and warm regions is of the same order.

Presolar oxide grains have been previously divided into several groups (Group 1 to 4) based on their isotopic compositions, which can be tied to several stellar sources. Much of available data was acquired on large grains, which may not be fully representative of the presolar grain population present in meteorites. We present here new O isotopic data for 74 small presolar oxide grains (~200 nm in diameter on average) from Orgueil and Al-Mg isotopic systematics for 25 of the grains. Based on data-model comparisons, we show that (i) Group 1 and Group 2 grains more likely originated in low-mass first-ascent (red giant branch; RGB) and/or second-ascent (asymptotic giant branch; AGB) red giant stars and (ii) Group 1 grains with (26Al/27Al)0 >= 5x10^-3 and Group 2 grains with (26Al/27Al)0 <= 1x10^-2 all likely experienced extra circulation processes in their parent low-mass stars but under different conditions, resulting in proton-capture reactions occurring at enhanced temperatures. We do not find any large 25Mg excess in Group 1 oxide grains with large 17O enrichments, which provides evidence that 25Mg is not abundantly produced in low-mass stars. We also find that our samples contain a larger proportion of Group 4 grains than so far suggested in the literature for larger presolar oxide grains (~400 nm). We also discuss our observations in the light of stellar dust production mechanisms.

Aiming to delineate the physical framework of blazars, we present an effective method to estimate four important parameters based on the idea proposed by \citet{BK95}, including the upper limit of central black hole mass $M$, the Doppler factor $\delta$, the distance along the axis to the site of the $\gamma$-ray production $d$ (which then can be transformed into the location of $\gamma$-ray-emitting region $R_{\gamma}$) and the propagation angle with respect to the axis of the accretion disk $\Phi$. To do so, we adopt an identical sample with 809 {\it Fermi}-LAT-detected blazars which had been compiled in \citet{Pei20PASA}. These four derived parameters stepping onto the stage may shed new light on our knowledge regarding $\gamma$-ray blazars. With regard to the paper of \citet{BK95}, we obtain several new perspectives, mainly in: (1) putting forward an updated demarcation between BL Lacs and FSRQs based on the relation between broad-line region luminosity and disk luminosity both measured in Eddington units, i.e., $L_{\rm disk}/L_{\rm Edd}=4.68\times10^{-3}$, indicating that there are some differences between BL Lacs and FSRQs on the accretion power in the disk; (2) proposing that there is a so-called `appareling zone', a potential transition field between BL Lacs and FSRQs where the changing-look blazars perhaps reside; (3) the location of $\gamma$-ray emission region is principally constrained outside the broad-line region, and for some BL Lacs are also away from the dusty molecular torus, which means the importance of emission components in the jet.

We derive a corrected analytical solution for the propagation and enhanced phase mixing of torsional Alfv\'en waves, in a potential magnetic field with exponentially divergent field lines, embedded in a stratified solar corona. Further we develop a code named TAWAS which calculates the analytic solution describing torsional Alfv\'en waves using IDL software language. We then use TAWAS to demonstrate that both our correction to the analytic solution and the inclusion of wave reflection have a significant impact on Alfv\'en wave damping. We continue to utilise TAWAS by performing a parameter study in order to identify the conditions under which enhanced phase mixing is strongest. We find that phase mixing is the strongest for high frequency Alfv\'en waves in magnetic fields with highly divergent field lines and without density stratification. We then present a finite difference solver, Wigglewave, which solves the linearised evolution equations for the system directly. Comparing solutions from TAWAS and Wigglewave we see that our analytical solution is accurate within the limits of the WKB approximation but under-reports the wave damping, caused by enhanced phase mixing, beyond the WKB limit. Both TAWAS and Wigglewave solve the linearised governing equations and not the complete nonlinear MHD equations. Paper II will consider simulations that solve the full MHD equations including important nonlinear effects.

Mars exploration motivates the search for extraterrestrial life, the development of space technologies, and the design of human missions and habitations. Here we seek new insights and pose unresolved questions relating to the natural history of Mars, habitability, robotic and human exploration, planetary protection, and the impacts on human society. Key observations and findings include:(1)high escape rates of early Mars' atmosphere, including loss of water, impact present-day habitability;(2)putative fossils on Mars will likely be ambiguous biomarkers for life;(3)microbial contamination resulting from human habitation is unavoidable;(4)based on Mars' current planetary protection category, robotic payload(s) should characterize the local martian environment for any life-forms prior to human habitation. Some of the outstanding questions are:(1)which interpretation of the hemispheric dichotomy of the planet is correct;(2)to what degree did deep-penetrating faults transport subsurface liquids to Mars' surface;(3)in what abundance are carbonates formed by atmospheric processes;(4)what properties of martian meteorites could be used to constrain their source locations;(5)the origin(s) of organic macromolecules;(6)was/is Mars inhabited;(7)how can missions designed to uncover microbial activity in the subsurface eliminate potential false positives caused by microbial contaminants from Earth;(8)how can we ensure that humans and microbes form a stable and benign biosphere;(9)should humans relate to putative extraterrestrial life from a biocentric viewpoint (preservation of all biology), or anthropocentric viewpoint of expanding habitation of space? Studies of Mars' evolution can shed light on the habitability of extrasolar planets. In addition, Mars exploration can drive future policy developments and confirm (or put into question) the feasibility and/or extent of human habitability of space.

Accreting millisecond X-ray pulsars (AMXPs) show burst oscillations during thermonuclear explosions of the accreted plasma which are markedly different from those observed in non-pulsating low mass X-ray binaries. The AMXP XTE J1814-338 is known for having burst oscillations that are phase locked (constant phase difference) and coincident with the accretion powered pulsations during all its thermonuclear bursts but the last one. In this work we use a coherent timing analysis to investigate this phenomenon in more detail and with higher time resolution than was done in the past. We confirm that the burst oscillation phases are, on average, phase locked to the accretion powered pulsations. However, they also display moderate (<~ 0.1 cycles) drifts during each individual burst, showing a repeating pattern that is consistently observed according to the thermonuclear burst phase (rise, peak, tail). Despite the existence of these drifting patterns, the burst oscillation phases somehow are able to average out at almost the exact position of the accretion powered pulsations. We provide a kinematic description of the phenomenon and review the existing models in the literature. The phenomenon remains without a clear explanation, but we can place important constraints on the thermonuclear burst mechanism. In particular, the observations imply that the ignition point of the thermonuclear burst occurs close to the foot of the accretion column. We speculate that the burning fluid expands in a backward tilted accretion column trapped by the magnetic field, while at the same time the burning flame covers the surface.

The Double Asteroid Redirection Test (DART) mission will be the first test of a kinetic impactor as a means of planetary defense. In late 2022, DART will collide with Dimorphos, the secondary in the Didymos binary asteroid system. The impact will cause a momentum transfer from the spacecraft to the binary asteroid, changing the orbit period of Dimorphos and forcing it to librate in its orbit. Owing to the coupled dynamics in binary asteroid systems, the orbit and libration state of Dimorphos are intertwined. Thus, as the secondary librates, it also experiences fluctuations in its orbit period. These variations in the orbit period are dependent on the magnitude of the impact perturbation, as well as the system's state at impact and the moments of inertia of the secondary. In general, any binary asteroid system whose secondary is librating will have a non-constant orbit period on account of the secondary's fluctuating spin rate. The orbit period variations are typically driven by two modes: a long-period and short-period, each with significant amplitudes on the order of tens of seconds to several minutes. The fluctuating orbit period offers both a challenge and an opportunity in the context of the DART mission. Orbit period oscillations will make determining the post-impact orbit period more difficult, but can also provide information about the system's libration state and the DART impact.

Recent multi-frequency measurements of pulse widths W50 for the long-period pulsar J0250+5854 by Agar et al provide a unique insight to the emission process owing to its small polar-cap radius. The frequency-dependence of W50 can be simply understood as a consequence of the emitting plasma remaining under acceleration during the interval of radio emission. This is possible in a plasma of ions and protons but not in one of high-multiplicity electron-positron pairs. Extension of the model to the pulse profiles of the general pulsar population is considered briefly.

The solar corona routinely exhibits explosive activity, in particular coronal mass ejections and their accompanying eruptive flares, that have global-scale consequences. These events and their smaller counterparts, coronal jets, originate in narrow, sinuous filament channels. The key processes that form and evolve the channels operate on still smaller spatial scales and much longer time scales, culminating in a vast separation of characteristic lengths and times that govern these explosive phenomena. In this article, we describe implementation and tests of an efficient subgrid-scale model for generating eruptive structures in magnetohydrodynamics (MHD) coronal simulations. STITCH -- STatistical InjecTion of Condensed Helicity -- is a physics-based, reduced representation of helicity condensation: a process wherein small-scale vortical surface convection forms ubiquitous current sheets, and pervasive reconnection across the sheets mediates an inverse cascade of magnetic helicity and free energy, thereby forming the filament channels. STITCH abstracts these complex processes into a single new term, in the MHD Ohm's law and induction equation, which directly injects tangential magnetic flux into the low corona. We show that this approach is in very good agreement with a full helicity-condensation calculation that treats all of the dynamics explicitly, while enabling substantial reductions in temporal duration especially, but also in spatial resolution. In addition, we illustrate the flexibility of STITCH at forming localized filament channels and at energizing complex surface flux distributions that have sinuous boundaries. STITCH is simple to implement and computationally efficient, making it a powerful new technique for event-based, data-driven modeling of solar eruptions.

The immense power of gamma-ray bursts (GRBs) make them ideal probes of the early universe. By using absorption lines in the afterglows of high-redshift GRBs, astronomers can study the evolution of metals in the early universe. With an understanding of the nature of GRB progenitors, the rate and properties of GRBs observed at high redshift can probe the star formation history and the initial mass function of stars at high redshift. This paper presents a detailed study of the metallicity- and mass-dependence of the properties of long-duration GRBs under the black-hole accretion disk paradigm to predict the evolution of these properties with redshift. These models are calibrated on the current GRB observations and then used to make predictions for new observations and new missions (e.g. the proposed Gamow mission) studying high-redshift GRBs.

It is still unclear whether the evolution of protoplanetary disks, a key ingredient in the theory of planet formation, is driven by viscous turbulence or magnetic disk winds. As viscously evolving disks expand outward over time, the evolution of disk sizes is a discriminant test for studying disk evolution. However, it is unclear how the observed disk size changes over time if disk evolution is driven by magnetic disk winds. Combining the thermochemical code DALI with the analytical wind-driven disk evolution model presented in Tabone et al. (2021a), we study the time evolution of the observed gas outer radius as measured from CO rotational emission ($R_{\rm CO, 90\%}$). The evolution of $R_{\rm CO, 90\%}$ is driven by the evolution of the disk mass, as the physical radius stays constant over time. For a constant $\alpha_{\rm DW}$, an extension of the $\alpha-$Shakura-Sunyaev parameter to wind-driven accretion, $R_{\rm CO, 90\%}$ decreases linearly with time. Its initial size is set by the disk mass and the characteristic radius $R_c$, but only $R_c$ affects the evolution of $R_{\rm CO, 90\%}$, with a larger $R_c$ resulting in a steeper decrease of $R_{\rm CO, 90\%}$. For a time-dependent $\alpha_{\rm DW}$ $R_{\rm CO, 90\%}$ stays approximately constant during most of the disk lifetime until $R_{\rm CO, 90\%}$ rapidly shrinks as the disk dissipates. The constant $\alpha_{\rm DW}$-models are able to reproduce the observed gas disk sizes in the $\sim1-3$ Lupus and $\sim5-11$ Myr old Upper Sco star-forming regions. However, they likely overpredict the gas disk size of younger $(\lessapprox0.7\ \mathrm{Myr})$ disks.

The process of uniform supernovae explosions (SNe) is well investigated for all their types. However, observational data suggests that the SNe could be not spherically-symmetric. Modern multi-dimensional simulations of SNe demonstrate development of hydrodynamical instabilities during the explosion phase. But the configuration of a star and inhomogeneities prior to explosion could strongly affect how the SNe develops. In a number of papers on numerical modeling of pair-instability supernovae explosion (PISNe) considered the case when thermonuclear energy in the central region of a massive star is introduced by the series of several hot spots. It leads to the appearance of many fragments of hot matter behind the divergence shock wave. An observable manifestation of this may be the presence of peaks on light curves of gamma-ray burst associated with explosions of massive stars. The physical nature of such inhomogeneities is not evident and the number and size of spots is a conjecture. In this work, we study the possibility of formation of these inhomogeneities at the stage of the core-collapse (CC) in a massive star. To check this assumption, we chose analytic self-similar model of CC and investigated stability of solutions obtained from it with respect to small multidimensional perturbations. It shows there are no conditions where the collapse of a very massive star may remain stable, although, for a less massive star, it is possible. Using obtained relations, we found characteristic features of developing instability, thereby making it possible to estimate the amount and characteristic size of the inhomogeneities.

At ~50 Mpc, the Hydra I cluster of galaxies is among the closest cluster in the z=0 Universe, and an ideal environment to study dwarf galaxy properties in a cluster environment. We exploit deep imaging data of the Hydra I cluster to construct a new photometric catalog of dwarf galaxies in the cluster core, which is then used to derive properties of the Hydra I cluster dwarf galaxies population as well as to compare with other clusters. Moreover, we investigate the dependency of dwarf galaxy properties on their surrounding environment. The new Hydra I dwarf catalog contains 317 galaxies with luminosity between -18.5<$M_r$<-11.5 mag, a semi-major axis larger than ~200 pc (a=0.84 arcsec), of which 202 are new detections, previously unknown dwarf galaxies in the Hydra I central region. We estimate that our detection efficiency reaches 50% at the limiting magnitude $M_r$=-11.5 mag, and at the mean effective surface brightness $\overline{\mu}_{e,r}$=26.5 mag/$arcsec^2$. We present the standard scaling relations for dwarf galaxies and compare them with other nearby clusters. We find that there are no observational differences for dwarfs scaling relations in clusters of different sizes. We study the spatial distribution of galaxies, finding evidence for the presence of substructures within half the virial radius. We also find that mid- and high-luminosity dwarfs ($M_r$<-14.5 mag) become on average redder toward the cluster center, and that they have a mild increase in $R_e$ with increasing clustercentric distance, similar to what is observed for the Fornax cluster. No clear clustercentric trends are reported with surface brightness and S\'ersic index. Considering galaxies in the same magnitude-bins, we find that for high and mid-luminosity dwarfs ($M_r$<-13.5 mag) the g-r color is redder for the brighter surface brightness and higher S\'ersic n index objects.

Aims: Contamination from bright diffuse Galactic thermal and non-thermal radio emission poses crucial challenges in experiments aiming to measure the 21-cm signal of neutral hydrogen from the Cosmic Dawn (CD) and Epoch of Reionization (EoR). If not included in calibration, this diffuse emission can severely impact the analysis and signal extraction in 21-cm experiments. We examine large-scale diffuse Galactic emission at 122~MHz, around the North Celestial Pole, using the Amsterdam-ASTRON Radio Transient Facility and Analysis Centre (AARTFAAC)- High Band Antenna (HBA) system. Methods: In this pilot project, we present the first-ever wide-field image produced with a single sub-band of the data recorded with the AARTFAAC-HBA system. We demonstrate two methods: multiscale CLEAN and shapelet decomposition, to model the diffuse emission revealed in the image. We use angular power spectrum metric to quantify different components of the emission and compare the performance of the two diffuse structure modelling approaches. Results: We find that multiscale CLEAN is suitable to model the compact and diffuse structures on a wide range of angular scales, whereas the shapelet decomposition method better models the large scales, which are of the order of a few degrees and wider.The point sources dominate the angular power spectrum of the emission in the field on scales $\ell\gtrsim100$ ($\lesssim 2$~degree), and the diffuse emission dominates on scales with $\ell\lesssim200$. The diffuse emission has a brightness temperature variance of $\Delta^2_{\ell=180} = (145.64 \pm 13.45)~{\rm K}^2$ at 122~MHz on angular scales of 1~degree, and is consistent with a power-law following $C_{\ell}\propto \ell^{-2.0}$.

This research provides an analysis of extreme events in the solar wind and in the magnetosphere due to disturbances of the solar wind. Extreme value theory has been applied to a 20 year data set from the Advanced Composition Explorer (ACE) spacecraft for the period 1998-2017. The solar proton speed, solar proton temperature, solar proton density and magnetic field have been analyzed to characterize extreme events in the solar wind. The solar wind electric field, vB$_{z}$ has been analyzed to characterize the impact from extreme disturbances in the solar wind to the magnetosphere. These extreme values were estimated for one-in-40 and one-in-80 years events, which represent two and four times the range of the original data set. The estimated values were verified by comparison with measured values of extreme events recorded in previous years. Finally, our research also suggests the presence of an upper boundary in the magnitudes under study.

The formation and decay of metastable bound states can significantly decrease the thermal-relic dark matter density, particularly for dark matter masses around and above the TeV scale. Incorporating bound-state effects in the dark matter thermal decoupling requires in principle a set of coupled Boltzmann equations for the bound and unbound species. However, decaying bound states attain and remain in a quasi-steady state. Here we prove in generality that this reduces the coupled system into a single Boltzmann equation of the standard form, with an effective cross-section that describes the interplay among bound-state formation, ionisation, transitions and decays. We derive a closed-form expression for the effective cross-section for an arbitrary number of bound states, and show that bound-to-bound transitions can only increase it. Excited bound levels may thus decrease the dark matter density more significantly than otherwise estimated. Our results generalise the Saha ionisation equilibrium to metastable bound states, potentially with applications beyond the dark matter thermal decoupling.

The impact of interplanetary shocks on the magnetosphere can trigger magnetic substorms that intensify auroral electrojet currents. These currents enhance ground magnetic field perturbations (d$B$/d$t$), which in turn generate geomagnetically induced currents (GICs) that can be detrimental to power transmission infrastructure. We perform a comparative study of d$B$/d$t$ variations in response to two similarly strong shocks, but with one being nearly frontal, and the other, highly inclined. Multi-instrument analyses by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Los Alamos National Laboratory spacecraft show that nightside substorm-time energetic particle injections are more intense and occur faster in the case of the nearly head-on impact. The same trend is observed in d$B$/d$t$ variations recorded by THEMIS ground magnetometers. THEMIS all-sky imager data show a fast and clear poleward auroral expansion in the first case, which does not clearly occur in the second case. Strong field-aligned currents computed with the spherical elementary current system (SECS) technique occur in both cases, but the current variations resulting from the inclined shock impact are weaker and slower compared to the nearly frontal case. SECS analyses also reveal that geographic areas with d$B$/d$t$ surpassing the thresholds 1.5 and 5 nT/s, usually linked to high-risk GICs, are larger and occur earlier due to the symmetric compression caused by the nearly head-on impact. These results, with profound space weather implications, suggest that shock impact angles affect the geospace driving conditions and the location and intensity of the subsequent d$B$/d$t$ variations during substorm activity.

We have considered flat Friedmann-Robertson-Walker (FRW) model of the universe and reviewed the modified Chaplygin gas as the fluid source. Associated with the scalar field model, we have determined the Hubble parameter as a generating function in terms of the scalar field. Instead of hyperbolic function, we have taken Jacobi elliptic function and Abel function in the generating function and obtained modified Chaplygin-Jacobi gas (MCJG) and modified Chaplygin-Abel gas (MCAG) equation of states, respectively. Next, we have assumed that the universe filled in dark matter, radiation, and dark energy. The sources of dark energy candidates are assumed as MCJG and MCAG. We have constrained the model parameters by recent observational data analysis. Using $\chi^{2}$ minimum test (maximum likelihood estimation), we have determined the best fit values of the model parameters by OHD+CMB+BAO+SNIa joint data analysis. To examine the viability of the MCJG and MCAG models, we have determined the values of the deviations of information criteria like $\triangle$AIC, $\triangle$BIC and $\triangle$DIC. The evolutions of cosmological and cosmographical parameters (like equation of state, deceleration, jerk, snap, lerk, statefinder, Om diagnostic) have been studied for our best fit values of model parameters. To check the classical stability of the models, we have examined the values of square speed of sound $v_{s}^{2}$ in the interval $(0,1)$ for expansion of the universe.

Gravitational lenses are examined in de-Sitter (dS) background, for which the existence of the dS horizon is taken into account and hyperbolic trigonometry is used together with the hyperbolic angular diameter distance. Spherical trigonometry is used to discuss a gravitational lens in anti-de Sitter (AdS) background. The difference in the form among the dS/AdS lens equations and the exact lens equation in Minkowski background begins at the third order, when a small angle approximation is used in terms of lens and source planes. The angular separation of lensed images is decreased by the third-order deviation in the dS lens equation, while it is increased in AdS. In the present framework on the dS/AdS backgrounds, we discuss also the deflection angle of light, which does not include any term of purely the cosmological constant. Despite the different geometry, the deflection angle of light rays in hyperbolic and spherical geometry can take the same form. Through a coupling of the cosmological constant with lens mass, the separation angle of multiple images is larger (smaller) in dS (AdS) than in the flat case, for a given mass, source direction, and angular diameter distances among the lens, receiver and source.

We explore the possibilities of dark matter production in a U(1) extension of the standard model, also called the super-weak model. The freeze-in and freeze-out mechanisms are described in detail, assuming the lightest sterile neutrino in the model as the dark matter candidate. In both scenarios we present the favoured parameter space on the plane of super-weak coupling versus the new gauge boson mass. We discuss the experimental constraints limiting each case and outline possibilities of detection.

We study the axial quasinormal modes of hairy black holes in Gauss-Bonnet gravity with massive self-interacting scalar field. Two coupling functions of the scalar field to the Gauss-Bonnet invariant are adopted with one of them leading to black hole scalarization. The axial perturbations are studied via time evolution of the perturbation equation, and the effect of the scalar field mass and the self-interaction constant on the oscillation frequency and damping time is examined. We study as well the effect of nonzero scalar field potential on the critical point at which the perturbation equation loses hyperbolicity in the case of black hole scalarization. The results show that the non-zero scalar field potential extends the range of parameters where such loss of hyperbolicity is observed thus shrinking the region of stable black hole existence. This will have an important effect on the nonlinear dynamical simulation studies in massive scalar Gauss-Bonnet gravity.

Dark matter which scatters off ordinary matter with a relatively large cross section cannot be constrained by deep underground WIMP experiments, due to the energy loss of DM along its path. However, for a sufficiently large cross section, DM particles in the GeV mass range can be captured and thermalized within Earth, resulting in the accumulation of a DM atmosphere whose number density can be as large as $10^{14} \text{ cm}^{-3}$ at Earth's surface. (If the DM-nucleon interaction is attractive and bound states can be formed, most DM bind to nuclei and the density is much lower.) Neufeld and Brach-Neufeld performed experiments to constrain the DM-baryon scattering cross section of DM atmosphere around Earth, by measuring the evaporation rate of liquid nitrogen in a storage dewar within which various materials are immersed. If the DM-nitrogen cross section is in an appropriate range, room temperature DM would penetrate the dewar walls and scatter on the cold nitrogen, increasing its evaporation rate beyond the observed level. Limits on the cross section of DM with other materials than nitrogen are obtained by adding known amounts of different materials; if the material is heated by interactions with DM, that heats and evaporates the liquid nitrogen. Because Born approximation is in general invalid in much of the relevant cross section regime, it is non-trivial to interpret such experimental results as a limit on the DM-nucleon cross section. In this paper we derive the constraints on DM-baryon scattering, with the interaction modeled as a Yukawa potential sourced by the finite sized nucleus. Combining the dewar constraints with BBN, we exclude for the first time a cross section above $10^{-26} \text{ cm}^{2}$ for DM mass 0.8-5.5 GeV, for any sign interaction. One DM model that is constrained is sexaquark $(uuddss)$ DM with mass $m_X \sim 2$ GeV; it remains viable.