Sazuna/UAT_keywords huggingface dataset:
ELVES. III. Environmental Quenching by Milky Way-mass Hosts. Isolated dwarf galaxies usually exhibit robust star formation but satellite dwarf galaxies are often devoid of young stars, even in Milky Way-mass groups. Dwarf galaxies thus offer an important laboratory of the environmental processes that cease star formation. We explore the balance of quiescent and star-forming galaxies (quenched fractions) for a sample of ~400 satellite galaxies around 30 Local Volume hosts from the Exploration of Local VolumE Satellites (ELVES) Survey. We present quenched fractions as a function of satellite stellar mass, projected radius, and host halo mass, to conclude that overall, the quenched fractions are similar to the Milky Way, dropping below 50% at satellite M * ≈ 108 M ⊙. We may see hints that quenching is less efficient at larger radii. Through comparison with the semianalytic modeling code SatGen, we are also able to infer average quenching times as a function of satellite mass in host halo-mass bins. There is a gradual increase in quenching time with satellite stellar mass rather than the abrupt change from rapid to slow quenching that has been inferred for the Milky Way. We also generally infer longer average quenching times than recent hydrodynamical simulations. Our results are consistent with models that suggest a wide range of quenching times are possible via ram pressure stripping, depending on the clumpiness of the circumgalactic medium, the orbits of the satellites, and the degree of earlier preprocessing.

Keywords: Galaxy quenching, Dwarf galaxies
Probing the Efficiency of Tidal Synchronization in Outspiralling Double White Dwarf Binaries with LISA. Compact-object binaries including a white dwarf component are unique among gravitational-wave sources because their evolution is governed not just by general relativity and tides, but also by mass transfer. While the black hole and neutron star binaries observed with ground-based gravitational-wave detectors are driven to inspiral due to the emission of gravitational radiation-manifesting as a "chirp-like" gravitational-wave signal-the astrophysical processes at work in double white dwarf (DWD) systems can cause the inspiral to stall and even reverse into an outspiral. The dynamics of the DWD outspiral thus encode information about tides, which tell us about the behavior of electron-degenerate matter. We carry out a population study to determine the effect of the strength of tides on the distributions of the DWD binary parameters that the Laser Interferometer Space Antenna (LISA) will be able to constrain. We find that the strength of tidal coupling parameterized via the tidal synchronization timescale at the onset of mass transfer affects the distribution of gravitational-wave frequencies and frequency derivatives for detectably mass-transferring DWD systems. Using a hierarchical Bayesian framework informed by binary population synthesis simulations, we demonstrate how this parameter can be inferred using LISA observations. By measuring the population properties of DWDs, LISA will be able to probe the behavior of electron-degenerate matter.

Keywords: Accretion, White dwarf stars, AM Canum Venaticorum stars, Gravitational wave sources, Semi-detached binary stars, Tides
Modeling the 2022 τ-Herculid Outburst. The τ-Herculids (IAU shower number 61 TAH) is a minor meteor shower associated with comet 73P/Schwassmann-Wachmann 3, a Jupiter-family comet that disintegrated into several fragments in 1995. As a consequence of the nucleus breakup, possible increased meteor rates were predicted for 2022. On May 30-31, observation networks around the world reported two distinct peaks of TAH activity, around solar longitudes 69.°02 and 69.°42. This work examines the encounter conditions of the Earth with meteoroids ejected from 73P during the splitting event and on previous perihelion passages. Numerical simulations suggest that the main peak observed in 2022 was caused by meteoroids ejected from the splitting nucleus with four times the typical cometary gas expansion speed. High-resolution measurements performed with the Canadian Automated Meteor Observatory indicate that these meteoroids are fragile, with estimated bulk densities of 250 kg m-3. In contrast with the main peak, the first TAH activity peak in 2022 is best modeled with trails ejected prior to 1960. We find that ordinary cometary activity could have produced other TAH apparitions observed in the past, including in 1930 and 2017. The extension of our model to future years predicts significant returns of the shower in 2033 and 2049.

Keywords: Comets, Meteor streams, Meteoroids
Investigating the Time Evolution of the Thermal Emission from the Putative Neutron Star in SN 1987A for 50+ Years. Observations collected with the Atacama Large Millimeter/submillimeter Array (ALMA) and analysis of broadband X-ray spectra have recently suggested the presence of a central compact object (CCO) in SN 1987A. However, no direct evidence of the CCO has been found yet. Here we analyze Chandra X-ray observations of SN 1987A collected in 2007 and 2018, and synthesize 2027 Chandra and 2037 Lynx spectra of the faint inner region of SN 1987A. We estimate the temporal evolution of the upper limits of the intrinsic luminosity of the putative CCO in three epochs (2018, 2027, and 2037). We find that these upper limits are higher for higher neutron star (NS) kick velocities due to increased absorption from the surrounding cold ejecta. We compare NS cooling models with both the intrinsic luminosity limits obtained from the X-ray spectra and the ALMA constraints with the assumption that the observed blob of SN 1987A is primarily heated by thermal emission. We find that the synthetic Lynx spectra are crucial to constrain the physical properties of the CCO, which will be confirmed by future observations in the 2040s. We draw our conclusions based on two scenarios, namely the nondetection and detection of the NS by Lynx. If the NS is not detected, its kick velocity should be ≃700 km s-1. Furthermore, nondetection of the NS would suggest rapid cooling processes at the age of 40 yr, implying strong crust superfluidity. Conversely, in the case of NS detection, the mass of the NS envelope must be high.

Keywords: Neutron stars, X-ray astronomy, Supernova remnants, Compact objects, X-ray sources, Supernovae
Spatial Intermittency of Particle Distribution in Relativistic Plasma Turbulence. Relativistic magnetically dominated turbulence is an efficient engine for particle acceleration in a collisionless plasma. Ultrarelativistic particles accelerated by interactions with turbulent fluctuations form nonthermal power-law distribution functions in the momentum (or energy) space, f(γ)d γ ∝ γ -α  d γ, where γ is the Lorenz factor. We argue that in addition to exhibiting non-Gaussian distributions over energies, particles energized by relativistic turbulence also become highly intermittent in space. Based on particle-in-cell numerical simulations and phenomenological modeling, we propose that the bulk plasma density has lognormal statistics, while the density of the accelerated particles, n, has a power-law distribution function, $P(n){dn}\,\propto \,{n}^{-\beta }{dn}$ . We argue that the scaling exponents are related as β ≈ α + 1, which is broadly consistent with numerical simulations. Non-space-filling, intermittent distributions of plasma density and energy fluctuations may have implications for plasma heating and for radiation produced by relativistic turbulence.

Keywords: Plasma astrophysics, Relativistic fluid dynamics, Plasma physics
Nonzero Phase Shifts of Acoustic Waves in the Lower Solar Atmosphere Measured from Realistic Simulations and Their Role in Local Helioseismology. Previous studies analyzing the evanescent nature of acoustic waves in the lower solar atmosphere, up to 300 km above the photosphere, have shown an unexpected phase shift of an order of 1 s between different heights. Those studies investigated the spectral line Fe I λ6173.3, commonly used for helioseismic measurements. Such phase shifts can contribute to a misinterpretation of the measured travel times in local helioseismology, complicating inferences of, e.g., the deep meridional flow. In this study, we carry out phase shift computations using a simulated, fully radiative, and convective atmosphere from which the Fe I λ6173.3 line is synthesized. The resulting phase shifts as functions of frequency across multiple heights show nonzero values in evanescent waves, similar to what was found in observational data. Comparing the Doppler velocities estimated from the synthesized absorption line with the true velocities directly obtained from the simulated plasma motions, we find substantial differences in phase shifts between the two. This leads us to hypothesize that the nonadiabaticity of the solar atmosphere yields extra phase shift contributions to Doppler velocities. Finally, computing phase differences for different viewing angles reveals a systematic center-to-limb variation, similar to what is present in observations. Overall, this study helps to improve our understanding of the physical cause of the helioseismic center-to-limb effect. *Current Version: 0.00.

Keywords: Helioseismology, Solar atmosphere, Solar oscillations, Solar interior
Constraints on the Frequency and Mass Content of r-process Events Derived from Turbulent Mixing in Galactic Disks. Metal-poor stars in the Milky Way (MW) halo display large star-to-star dispersion in their r-process abundance relative to lighter elements. This suggests a chemically diverse and unmixed interstellar medium (ISM) in the early universe. This study aims to help shed light on the impact of turbulent mixing, driven by core-collapse supernovae (cc-SNe), on the r-process abundance dispersal in galactic disks. To this end, we conduct a series of simulations of small-scale galaxy patches which resolve metal-mixing mechanisms at parsec scales. Our setup includes cc-SNe feedback and enrichment from r-process sources. We find that the relative rate of the r-process events to cc-SNe is directly imprinted on the shape of the r-process distribution in the ISM with more frequent events causing more centrally peaked distributions. We consider also the fraction of metals that is lost on galactic winds and find that cc-SNe are able to efficiently launch highly enriched winds, especially in smaller galaxy models. This result suggests that smaller systems, e.g., dwarf galaxies, may require higher levels of enrichment in order to achieve similar mean r-process abundances as MW-like progenitors systems. Finally, we are able to place novel constraints on the production rate of r-process elements in the MW, $6\times {10}^{-7}{M}_{\odot }\,{\mathrm{yr}}^{-1}\lesssim {\dot{m}}_{\mathrm{rp}}\ll 4.7\times {10}^{-4}{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , imposed by accurately reproducing the mean and dispersion of [Eu/Fe] in metal-poor stars. Our results are consistent with independent estimates from alternate methods and constitute a significant reduction in the permitted parameter space.

Keywords: Galactic winds, Stellar feedback, R-process, Chemical abundances, Milky Way Galaxy physics, Interstellar medium, Metallicity
RAIKOU (来光): A General Relativistic, Multiwavelength Radiative Transfer Code. We present a general relativistic radiative transfer code RAIKOU (来光) for multiwavlength studies of spectra and images including the black hole shadows around Kerr black holes. Important radiative processes in hot plasmas around black holes, i.e., (cyclo-)synchrotron, bremsstrahlung emission/absorption, and Compton/inverse-Compton scattering, are incorporated. The Maxwell-Jüttner and single/broken power-law electron distribution functions are implemented to calculate the radiative transfer via both thermal and nonthermal electrons. Two calculation algorithms are implemented for studies of the images and broadband spectra. An observer-to-emitter ray-tracing algorithm, which inversely solves the radiative transfer equation from the observer screen to emitting plasmas, is suitable for an efficient calculations of the images, e.g., the black hole shadows observed by the Event Horizon Telescope, and spectra without Compton effects. On the other hand, an emitter-to-observer Monte Carlo algorithm, by which photons are transported with a Monte Carlo method including the effects of Compton/inverse-Compton scatterings, enables us to compute multiwavelength spectra, with their energy bands broadly ranging from radio to very high energy gamma-ray. The X-ray black hole shadows, which are formed via synchrotron emission and inverse-Compton scattering processes and will be observed in the future X-ray interferometry missions, can be also computed with this algorithm. The code is generally applicable to accretion flows around Kerr black holes with relativistic jets and winds/coronae with various mass accretion rates (i.e., radiatively inefficient accretion flows, super-Eddington accretion flows, and others). We demonstrate an application of the code to a radiatively inefficient accretion flow onto a supermassive black hole.

Keywords: Accretion, Black hole physics, High energy astrophysics, Relativistic jets, Computational methods, General relativity, Radiative transfer
Dynamically Forming Extremely Low-mass White Dwarf Binaries in Wide Orbits. The detection of a 0.2 M ⊙ extremely low-mass white dwarf (EW) in a wide orbit (P orb ≈ 450 days) with a 1.1 M ⊙ main-sequence companion, KIC 8145411, challenges our current understanding of how EWs form. The traditional channel for EW formation, via mass transfer from the EW's progenitor, is expected to form EW binaries in tight orbits. Indeed, the majority of known EWs are found in tight binaries with a median P orb ≈ 5.4 hr. Using numerical scattering experiments, we find that binary-binary strong encounters in star clusters can sufficiently widen the orbit of a typical EW binary, to explain the observed wide orbit of the KIC 8145411 system. The P orb distribution for EW binaries produced through binary-binary encounters is bimodal: one mode corresponds to the initial orbital period of the EW binary, while the other is near P orb ~ few 102 days, similar to the orbital period of the KIC 8145411 system. We find that the production of wide EW binaries that are also ejected from the cluster peaks at a star cluster mass of ~105 M ⊙ with a rate of ~10-3 Gyr-1. Assuming that 50% of all stars form in star clusters and an initial cluster mass function ∝m -2, we estimate a galactic formation rate of ~4.16 × 103 Gyr-1 for wide EW binaries.

Keywords: White dwarf stars, Stellar dynamics, Interacting binary stars, Computational methods
An Extension of the Athena++ Code Framework for Radiation-magnetohydrodynamics in General Relativity Using a Finite-solid-angle Discretization. We extend the general-relativistic magnetohydrodynamics (GRMHD) capabilities of Athena++ to incorporate radiation. The intensity field in each finite-volume cell is discretized in angle, with explicit transport in both space and angle properly accounting for the effects of gravity on null geodesics, and with matter and radiation coupled in a locally implicit fashion. Here we describe the numerical procedure in detail, verifying its correctness with a suite of tests. Motivated in particular by black hole accretion in the high-accretion-rate, thin-disk regime, we demonstrate the application of the method to this problem. With excellent scaling on flagship computing clusters, the port of the algorithm to the GPU-enabled AthenaK code now allows the simulation of many previously intractable radiation-GRMHD systems.

Keywords: Software documentation, Radiative magnetohydrodynamics, Black holes, Astronomy software, Computational methods, General relativity, Radiative transfer
Seven Reflares, a Mini Outburst, and an Outburst: High-amplitude Optical Variations in the Black Hole X-Ray Binary Swift J1910.2-0546. We present long-term (2012-2022) optical monitoring of the candidate black hole X-ray binary Swift J1910.2-0546 with the Faulkes Telescopes and Las Cumbres Observatory network. Following its initial bright 2012 outburst, we find that the source displayed a series of at least seven quasi-periodic, high-amplitude (~3 mag) optical reflares in 2013, with a recurrence time increasing from ~42 to ~49 days. In 2014, the source experienced a mini outburst with two peaks in the optical. We also study the recent 2022 outburst of the source at optical wavelengths, and perform a comparative analysis with the earlier rebrightenings. A single X-ray detection and only two radio detections were obtained during the 2013 reflaring period, and only optical detections were acquired in 2014. During the reflaring in both 2013 and 2014, the source showed bluer-when-brighter behavior, having optical colors consistent with blackbody heating and cooling between 4500 and 9500 K, i.e., the temperature range in which hydrogen starts to ionize. Finally, we compare the flaring behavior of the source to rebrightening events in other X-ray binaries. We show that the repeated reflarings of Swift J1910.2-0546 are highly unusual, and propose that they arise from a sequence of repetitive heating and cooling front reflections traveling through the accretion disk.

Keywords: Accretion, Jets, Optical astronomy, Stellar mass black holes, Low-mass x-ray binary stars
The SPHEREx Target List of Ice Sources (SPLICES). One of the primary objectives of the SPHEREx mission is to understand the origin of molecules such as H2O, CO2, and other volatile compounds at the early stages of planetary system formation. Because the vast majority of these compounds-typically exceeding 95%-exist in the solid phase rather than the gaseous phase in the systems of concern here, the observing strategy planned to characterize them is slightly unusual. Specifically, SPHEREx will target highly obscured sources throughout the Milky Way, and observe the species of concern in absorption against background illumination. SPHEREx spectrophotometry will yield ice column density measurements for millions of obscured Milky Way sources of all ages and types. By correlating those column densities with source ages, the SPHEREx mission will shed light on whether those molecules were formed in situ along with their nascent stellar systems, or whether instead they formed elsewhere and were introduced into those systems after their formation. To that end, this work describes version 7.1 of the SPHEREx target List of ICE Sources (SPLICES) for the community. It contains 8.6 × 106 objects brighter than W2 ~ 12 Vega mag over much of the sky, principally within a broad strip running the length of the Milky Way midplane, but also within high-latitude molecular clouds and even the Magellanic Clouds.

Keywords: Interstellar molecules, Interstellar dust, Sky surveys, Catalogs
Distribution and Kinematics of H I through Raman He II Spectroscopy of NGC 6302. The young planetary nebula NGC 6302 is known to exhibit Raman-scattered He II features at 6545 Å and 4851 Å. These features are formed through inelastic scattering of He II λλ 1025 and 972 with hydrogen atoms in the ground state, for which the cross sections are 1.2 × 10-21 cm2 and 1.4 × 10-22 cm2, respectively. We investigate the spectrum of NGC 6302 archived in the ESO Science Portal. Our Gaussian line-fitting analysis shows that the Raman-scattered He II features are broader and more redshifted than the hypothetical model Raman features that would be formed in a cold static H I medium. We adopt a simple scattering geometry consisting of a compact He II emission region surrounded by an H I medium to perform Monte Carlo simulations using the radiative transfer code STaRS. Our simulations show that the H I region is characterized by the H I column density N H I = 3 × 1021 cm-2, with the random speed component v ran = 10 km s-1 expanding with a speed ${v}_{\exp }=13\,\mathrm{km}\ {{\rm{s}}}^{-1}$ from the He II emission region. Based on our best-fit parameters, we estimate the H I mass of the neutral medium M H I ≃ 1.0 × 10-2 M ☉, pointing out the usefulness of Raman He II spectroscopy as a tool to trace H I components.

Keywords: High resolution spectroscopy, Radiative transfer simulations, Planetary nebulae, Radiative transfer
Effects of the Galactic Magnetic Field on the UHECR Correlation Studies with Starburst Galaxies. We estimate the biases caused by the coherent deflection of cosmic rays due to the Galactic magnetic field (GMF) in maximum likelihood analyses for searches of ultrahigh-energy cosmic-ray sources in the literature. We simulate mock event data sets with a set of assumptions for the starburst galaxy source model, coherent deflection by a GMF model, and mixed-mass composition. We then conduct a maximum likelihood analysis without accounting for the GMF in the same manner as previous studies. We find that the anisotropic fraction f ani is estimated to be systematically lower than the true value. We estimate the true parameters that are compatible with the best-fit parameters that were reported, and find that except for a narrow region with a large anisotropic fraction and a small separation angular scale, a wide parameter space is still compatible with the experimental results. We also develop a maximum likelihood method that takes the GMF model into account and confirm in Monte Carlo simulations that we can estimate the true parameters within a 1σ contour under the ideal condition that we know the event-by-event mass and the GMF.

Keywords: Ultra-high-energy cosmic radiation, Cosmic ray astronomy, Cosmic ray sources, Cosmic rays
Diverse Molecular Structures across the Whole Star-forming Disk of M83: High-fidelity Imaging at 40 pc Resolution. We present Atacama Large Millimeter/submillimeter Array (ALMA) imaging of molecular gas across the full star-forming disk of the barred spiral galaxy M83 in CO(J = 1-0). We jointly deconvolve the data from ALMA's 12 m, 7 m, and Total Power arrays using the MIRIAD package. The data have a mass sensitivity and resolution of 104 M ⊙ (3σ) and 40 pc-sufficient to detect and resolve a typical molecular cloud in the Milky Way with a mass and diameter of 4 × 105 M ⊙ and 40 pc, respectively. The full disk coverage shows that the characteristics of molecular gas change radially from the center to outer disk, with the locally measured brightness temperature, velocity dispersion, and integrated intensity (surface density) decreasing outward. The molecular gas distribution shows coherent large-scale structures in the inner part, including the central concentration, offset ridges along the bar, and prominent molecular spiral arms. However, while the arms are still present in the outer disk, they appear less spatially coherent, and even flocculent. Massive filamentary gas concentrations are abundant even in the interarm regions. Building up these structures in the interarm regions would require a very long time (≳100 Myr). Instead, they must have formed within stellar spiral arms and been released into the interarm regions. For such structures to survive through the dynamical processes, the lifetimes of these structures and their constituent molecules and molecular clouds must be long (≳100 Myr). These interarm structures host little or no star formation traced by Hα. The new map also shows extended CO emission, which likely represents an ensemble of unresolved molecular clouds.

Keywords: Molecular gas, Spiral galaxies, Millimeter astronomy, Molecular clouds, Star formation, Interstellar medium, CO line emission