Sazuna/UAT_keywords huggingface dataset:
SN2019wxt: An Ultrastripped Supernova Candidate Discovered in the Electromagnetic Follow-up of a Gravitational Wave Trigger. We present optical, radio, and X-ray observations of a rapidly evolving transient SN2019wxt (PS19hgw), discovered during the search for an electromagnetic counterpart to the gravitational-wave (GW) trigger S191213g. Although S191213g was not confirmed as a significant GW event in the off-line analysis of LIGO-Virgo data, SN2019wxt remained an interesting transient due to its peculiar nature. The optical/near-infrared (NIR) light curve of SN2019wxt displayed a double-peaked structure evolving rapidly in a manner analogous to currently known ultrastripped supernovae (USSNe) candidates. This double-peaked structure suggests the presence of an extended envelope around the progenitor, best modeled with two components: (i) early-time shock-cooling emission and (ii) late-time radioactive 56Ni decay. We constrain the ejecta mass of SN2019wxt at M ej ≈ 0.20M ☉, which indicates a significantly stripped progenitor that was possibly in a binary system. We also followed up SN2019wxt with long-term Chandra and Jansky Very Large Array observations spanning ~260 days. We detected no definitive counterparts at the location of SN2019wxt in these long-term X-ray and radio observational campaigns. We establish the X-ray upper limit at 9.93 × 10-17 erg cm-2 s-1 and detect an excess radio emission from the region of SN2019wxt. However, there is little evidence for SN1993J- or GW170817-like variability of the radio flux over the course of our observations. A substantial host-galaxy contribution to the measured radio flux is likely. The discovery and early-time peak capture of SN2019wxt in optical/NIR observations during EMGW follow-up observations highlight the need for dedicated early, multiband photometric observations to identify USSNe.

Keywords: X-ray astronomy, Radio interferometry, Ejecta, Core-collapse supernovae, Extragalactic radio sources, Spectral line identification, Transient sources, Gravitational wave sources, Transient detection, X-ray sources, Stellar remnants, Supernovae
Relativistic Corrections in White Dwarf Asteroseismology. With the precision now afforded by modern space-based photometric observations from the retired K2 and current TESS missions, the effects of general relativity (GR) may be detectable in the light curves of pulsating white dwarfs (WDs). Almost all WD models are calculated using a Newtonian description of gravity and hydrodynamics. To determine if the inclusion of GR leads to observable effects, we used idealized models of compact stars and made side-by-side comparisons of mode periods computed using a: (i) Newtonian and (ii) GR description of the equilibrium structure and nonradial pulsations. For application to WDs, it is only necessary to include the first post-Newtonian (1PN) approximation to GR. The mathematical nature of the linear nonradial pulsation problem is then qualitatively unchanged and the GR corrections can be written as extensions of the classic Dziembowski equations. As such, GR effects might easily be included in existing asteroseismology codes. The idealized stellar models are (i) 1PN relativistic polytropes and (ii) stars with a cold degenerate electron equation of state featuring a near-surface chemical transition from μ  e  = 2 to μ  e  = 1, simulating a surface hydrogen layer. A comparison of Newtonian and 1PN normal mode periods reveals fractional differences in the order of the surface gravitational redshift z. For a typical WD, this fractional difference is ~10-4 and is greater than the period uncertainty σ Π/Π of many WD pulsation modes observed by TESS. Consistent theoretical modeling of periods observed in these stars should, in principle, include GR effects to 1PN order.

Keywords: Gravitation, White dwarf stars, Asteroseismology, General relativity
Testing SALT Approximations with Numerical Radiation Transfer Code. I. Validity and Applicability. Absorption line spectroscopy offers one of the best opportunities to constrain the properties of galactic outflows and the environment of the circumgalactic medium. Extracting physical information from line profiles is difficult; however, for the physics governing the underlying radiation transfer is complicated and depends on many different parameters. Idealized analytical models are necessary to constrain the large parameter spaces efficiently, but are typically plagued by model degeneracy and systematic errors. Comparison tests with idealized numerical radiation transfer codes offer an excellent opportunity to confront both of these issues. In this paper, we present a detailed comparison between SALT, an analytical radiation transfer model for predicting UV spectra of galactic outflows, with the numerical radiation transfer software, RASCAS. Our analysis has led to upgrades to both models including an improved derivation of SALT and a customizable adaptive mesh refinement routine for RASCAS. We explore how well SALT, when paired with a Monte Carlo fitting procedure, can recover flow parameters from nonturbulent and turbulent flows. Overall we find that turbulence leads to biases in the recovery of kinematic parameters and the optical depth, but find that derived quantities (e.g., mass outflow rates, column density, etc.) are still well recovered. From the analysis, we estimate average uncertainties in our ability to measure metal flow rates spanning 0.65 (0.95) dex in M ⊙ yr-1 and uncertainties spanning 0.54 (0.94) dex in cm-2 for column densities at a resolution of 20 (100) km s-1 and signal-to-noise ratio = 10.

Keywords: Galactic winds, Monte Carlo methods, Ultraviolet spectroscopy, Analytical mathematics, Interstellar absorption, Radiative transfer, Circumgalactic medium, Radiative transfer simulations
The Planetary Accretion Shock. III. Smoothing-free 2.5D Simulations and Calculation of Hα Emission. Surveys have looked for Hα emission from accreting gas giants but found very few objects. Analyses of the detections and nondetections have assumed that the entire gas flow feeding the planet is in radial freefall. However, hydrodynamical simulations suggest that this is far from reality. We calculate the Hα emission from multidimensional accretion onto a gas giant, following the gas flow from Hill sphere scales down to the circumplanetary disk (CPD) and the planetary surface. We perform azimuthally symmetric radiation hydrodynamics simulations around the planet and use modern tabulated gas and dust opacities. Crucially, contrasting with most previous simulations, we do not smooth the gravitational potential but do follow the flow down to the planetary surface, where grid cells are 0.01 Jupiter radii small. We find that roughly only 1% of the net gas inflow into the Hill sphere directly reaches the planet. As expected for ballistic infall trajectories, most of the gas falls at too large a distance on the CPD to generate Hα. Including radiation transport removes the high-velocity subsurface flow previously seen in hydrodynamics-only simulations, so that only the free planet surface and the inner regions of the CPD emit substantial Hα. Unless magnetospheric accretion, which we neglect here, additionally produces Hα, the corresponding Hα production efficiency is much smaller than usually assumed, which needs to be taken into account when analyzing (non)detection statistics.

Keywords: Accretion, Hydrodynamical simulations, H alpha photometry, Radiative transfer, Shocks, Planet formation
The Way of Water: ALMA Resolves H<SUB>2</SUB>O Emission Lines in a Strongly Lensed Dusty Star-forming Galaxy at z ∼ 3.1. We report Atacama Large Millimeter/submillimeter Array (ALMA) high-resolution (≲0.3″) observations of water emission lines p-H2O(202 - 111), o-H2O(321 - 312), p-H2O(422 - 413), in the strongly lensed galaxy HATLASJ113526.2-01460 at redshift z ~3.1. From the lensing-reconstructed maps of water emission and line profiles, we infer the general physical properties of the interstellar medium (ISM) in the molecular clouds where the lines arise. We find that the water vapor lines o-H2O(321 - 312), p-H2O(422 - 413) are mainly excited by far-infrared (FIR) pumping from dust radiation in a warm and dense environment, with dust temperatures ranging from 70 to ~100 K, as suggested by the line ratios. The p-H2O(202 - 111) line, instead, is excited by a complex interplay between FIR pumping and collisional excitation in the dense core of the star-forming region. This scenario is also supported by the detection of the medium-level excitation of CO resulting in the line emission CO (J = 8-7). Thanks to the unprecedented high resolution offered by the combination of ALMA capabilities and gravitational lensing, we discern the different phases of the ISM and locate the hot molecular clouds into a physical scale of ~500 pc. We discuss the possibility of J1135 hosting an active galactic nucleus in its accretion phase. Finally, we determine the relation between the water emission lines and the total IR luminosity of J1135, as well as the star formation rate as a function of water emission intensities, comparing the outcomes to local and high-z galactic samples from the literature.

Keywords: Interstellar thermal emission, Star forming regions
Search for Ultra-high-energy Photons from Gravitational Wave Sources with the Pierre Auger Observatory. A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with the Pierre Auger Observatory. Due to the distinctive properties of photon interactions and to the background expected from hadronic showers, a subset of the most interesting GW events is selected based on their localization quality and distance. Time periods of 1000 s around and 1 day after the GW events are analyzed. No coincidences are observed. Upper limits on the UHE photon fluence from a GW event are derived that are typically at ~7 MeV cm-2 (time period 1000 s) and ~35 MeV cm-2 (time period 1 day). Due to the proximity of the binary neutron star merger GW170817, the energy of the source transferred into UHE photons above 40 EeV is constrained to be less than 20% of its total GW energy. These are the first limits on UHE photons from GW sources.

Keywords: Ultra-high-energy cosmic radiation, Transient sources, Gravitational wave sources, Cosmic ray showers, Particle astrophysics
Magnetic-reconnection-driven Turbulence and Turbulent Reconnection Acceleration. This paper employs an MHD-PIC method to perform numerical simulations of magnetic-reconnection-driven turbulence and turbulent reconnection acceleration of particles. Focusing on the dynamics of the magnetic reconnection, the properties of self-driven turbulence, and the behavior of particle acceleration, we find the following: (1) When reaching a statistically steady state of the self-driven turbulence, the magnetic energy is almost released by 50%, while the kinetic energy of the fluid increases by no more than 15%. (2) The properties of reconnection-driven turbulence are more complex than the traditional turbulence driven by an external force. (3) The strong magnetic field tends to enhance the turbulent reconnection efficiency to accelerate particles more efficiently, resulting in a hard spectral energy distribution. Our study provides a particular perspective on understanding turbulence properties and turbulent-reconnection-accelerated particles.

Keywords: Interplanetary particle acceleration, Radiative magnetohydrodynamics, Interstellar dynamics
FAST Polarization Mapping of the Supernova Remnant VRO 42.05.01. We have obtained the polarization data cube of the supernova remnant (SNR) VRO 42.05.01 at 1240 MHz using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). Three-dimensional Faraday synthesis is applied to the FAST data to derive the Faraday depth spectrum. The peak Faraday depth map shows a large area of enhanced foreground rotation measure (RM) of ~60 rad m-2 extending along the remnant's "wing" section, which coincides with a large-scale H I shell at -20 km s-1. The two depolarization patches within the "wing" region with RMs of 97 rad m-2 and 55 rad m-2 coincide with two H I structures in the H I shell. Faraday screen model fitting on the Canadian Galactic Plane Survey 1420 MHz full-scale polarization data reveals a distance of (0.7-0.8)d SNR in front of the SNR with enhanced regular magnetic field there. The highly piled-up magnetic field indicates that the H I shell at -20 km s-1 could originate from an old evolved SNR.

Keywords: Supernova remnants, Interstellar magnetic fields, Interstellar synchrotron emission
Reinterpreting the Polluted White Dwarf SDSS J122859.93+104032.9 in Light of Thermohaline Mixing Models: More Polluting Material from a Larger Orbiting Solid Body. The polluted white dwarf (WD) system SDSS J122859.93+104032.9 (SDSS J1228) shows variable emission features interpreted as originating from a solid core fragment held together against tidal forces by its own internal strength, orbiting within its surrounding debris disk. Estimating the size of this orbiting solid body requires modeling the accretion rate of the polluting material that is observed mixing into the WD surface. That material is supplied via sublimation from the surface of the orbiting solid body. The sublimation rate can be estimated as a simple function of the surface area of the solid body and the incident flux from the nearby hot WD. On the other hand, estimating the accretion rate requires detailed modeling of the surface structure and mixing in the accreting WD. In this work, we present MESA WD models for SDSS J1228 that account for the thermohaline instability and mixing in addition to heavy element sedimentation to constrain accurately the sublimation and accretion rate necessary to supply the observed pollution. We derive a total accretion rate of ${\dot{M}}_{\mathrm{acc}}=1.8\times {10}^{11}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ , several orders of magnitude higher than the ${\dot{M}}_{\mathrm{acc}}=5.6\times {10}^{8}\,{\rm{g}}\,{{\rm{s}}}^{-1}$ estimate obtained in earlier efforts. The larger mass accretion rate implies that the minimum estimated radius of the orbiting solid body is ${r}_{\min }$ = 72 km, which, although significantly larger than prior estimates, still lies within the upper bounds (a few hundred kilometers) for which the internal strength could no longer withstand the tidal forces from the gravity of the WD.

Keywords: Stellar accretion disks, White dwarf stars, Planetary system evolution, Stellar diffusion
Hydrodynamic Mixing of Accretion Disk Outflows in Collapsars: Implications for r-process Signatures. The astrophysical environments capable of triggering heavy-element synthesis via rapid neutron capture (the r-process) remain uncertain. While binary neutron star mergers (NSMs) are known to forge r-process elements, certain rare supernovae (SNe) have been theorized to supplement-or even dominate-r-production by NSMs. However, the most direct evidence for such SNe, unusual reddening of the emission caused by the high opacities of r-process elements, has not been observed. Recent work identified the distribution of r-process material within the SN ejecta as a key predictor of the ease with which signals associated with r-process enrichment could be discerned. Though this distribution results from hydrodynamic processes at play during the SN explosion, thus far it has been treated only in a parameterized way. We use hydrodynamic simulations to model how disk winds-the alleged locus of r-production in rare SNe-mix with initially r-process-free ejecta. We study mixing as a function of the wind mass, wind duration, and the initial SN explosion energy, and find that it increases with the first two of these and decreases with the third. This suggests that SNe accompanying the longest long-duration gamma-ray bursts are promising places to search for signs of r-process enrichment. We use semianalytic radiation transport to connect hydrodynamics to electromagnetic observables, allowing us to assess the mixing level at which the presence of r-process material can be diagnosed from SN light curves. Analytic arguments constructed atop this foundation imply that a wind-driven r-process-enriched SN model is unlikely to explain standard energetic SNe.

Keywords: R-process, Core-collapse supernovae
Statistical Study of the Correlation between Solar Energetic Particles and Properties of Active Regions. The flux of energetic particles originating from the Sun fluctuates during the solar cycles. It depends on the number and properties of active regions (ARs) present in a single day and associated solar activities, such as solar flares and coronal mass ejections. Observational records of the Space Weather Prediction Center NOAA enable the creation of time-indexed databases containing information about ARs and particle flux enhancements, most widely known as solar energetic particle (SEP) events. In this work, we utilize the data available for solar cycles 21-24 and the initial phase of cycle 25 to perform a statistical analysis of the correlation between SEPs and properties of ARs inferred from the McIntosh and Hale classifications. We find that the complexity of the magnetic field, longitudinal location, area, and penumbra type of the largest sunspot of ARs are most correlated with the production of SEPs. It is found that most SEPs (≈60%, or 108 out of 181 considered events) were generated from an AR classified with the "k" McIntosh subclass as the second component, and these ARs are more likely to produce SEPs if they fall in a Hale class containing a δ component. The resulting database containing information about SEP events and ARs is publicly available and can be used for the development of machine learning models to predict the occurrence of SEPs.

Keywords: Sunspots, Solar active regions, Solar activity, Solar-terrestrial interactions, Solar particle emission
Enhanced Black Hole Mergers in Active Galactic Nucleus Disks due to Precession-induced Resonances. Recent studies have shown that active galactic nucleus (AGN) disks can host sources of gravitational waves. Compact binaries can form and merge in AGN disks through their interactions with the gas and other compact objects in the disk. It is also possible for the binaries to shorten the merging timescale due to eccentricity excitation caused by perturbations from the supermassive black hole (SMBH). In this paper, we focus on effects due to precession-induced (eviction-like) resonances, where the nodal and apsidal precession rates of the binary are commensurable with the mean motion of the binary around the SMBH. We focus on intermediate-mass black hole (IMBH)-stellar-mass black hole binaries and consider binary orbit inclined from the circum-IMBH disk, which leads to the orbital J 2 precession. We show that if a binary is captured in these resonances and is migrating toward the companion, it can undergo large eccentricity and inclination variations. We derive analytical expressions for the location of fixed points, libration timescale, and width for these resonances and identify two resonances in the near-coplanar regime (the evection and eviction resonances) as well as two resonances in the near-polar regime that can lead to mergers. We also derive analytical expressions for the maximum eccentricity that a migrating binary can achieve for given initial conditions. Specifically, the maximum eccentricity can reach 0.9 when captured in these resonances before orbital decay due to gravitational-wave emission dominates, and the capture is only possible for slow migration (~10 Myr) two to three orders of magnitude longer than the resonance libration timescale. We also show that capture into multiple resonances is possible and can further excite eccentricities.

Keywords: Three-body problem, Perturbation methods, Active galactic nuclei, Black holes
A Mixture of LBG Overdensities in the Fields of Three 6 &lt; z &lt; 7 Quasars: Implications for the Robustness of Photometric Selection. The most luminous quasars at z &gt; 6 are suspected to be both highly clustered and to reside in the most massive dark matter halos in the early universe, making them prime targets to search for galaxy overdensities and/or protoclusters. We search for Lyman-break dropout-selected galaxies using HST WFC3/ACS broadband imaging in the fields of three 6 &lt; z &lt; 7 quasars, as well as for their simultaneously observed coordinated parallel fields, and constrain their photometric redshifts using EAZY. One field, J0305-3150, shows a volume density 10× higher than the blank-field UV luminosity function (UVLF) at M UV &lt; -20, with tentative evidence of a 3σ overdensity in its parallel field located 15 cMpc away. Another field, J2054-0005, shows an angular overdensity within 500 ckpc from the quasar, but this is still consistent with UVLF predictions within 3σ, while the last field, J2348-3054, shows no enhancement. We discuss methods for reducing uncertainty in overdensity measurements when using photometric selection and show that we can robustly select Lyman-break galaxies (LBGs) consistent with being physically associated with the quasar, corroborated by existing JWST/NIRCam WFSS data in the J0305 field. Even accounting for incompleteness, the overdensities in J0305 and J2054 are higher for brighter galaxies at short angular separations, suggesting preferential enhancement of more massive galaxies in the quasar's immediate vicinity. Finally, we compare the population of LBGs with previously identified [C II] and millimeter-continuum companions. The LBG overdensities are not accompanied by an enhanced number of dusty galaxies, suggesting that the overdense quasar fields are not in the bursty star-forming phase sometimes seen in high-redshift protoclusters.

Keywords: High-redshift galaxy clusters, Quasars, Hubble Space Telescope, Damped Lyman-alpha systems, Lyman-break galaxies, High-redshift galaxies
Implications of a Possible Spectral Structure of Cosmic-Ray Protons Unveiled by the DAMPE. The recent observations revealed that the cosmic-ray (CR) proton spectrum showed a complex structure: the hardening at ~200 GeV and softening at ~10 TeV. However, so far, the physical origins of this spectral feature remain strongly debated. In this work, we simulate the acceleration of CR protons in a nearby supernova remnant (SNR) by solving numerically the hydrodynamic equations and the equation for the quasi-isotropic CR momentum distribution in the spherically symmetrical case to derive the spectrum of protons injected into the interstellar medium, and then simulate the propagation process of those accelerated CR particles to calculate the proton fluxes reaching the Earth. Besides, we use the DRAGON numerical code to calculate the large-scale CR proton spectrum. Our simulated results are in good agreement with the observed data (including the observed data of proton fluxes and dipole anisotropy). We conclude that the spectral feature of CR protons in this energy band may originate from the superposition of the distribution from the nearby SNR and background diffusive CR component. We find that the release of particles from this nearby SNR has a time delay. Besides, it can be found that the nonlinear response of energetic particles, the release time of CR protons, and age of the local SNR can leave strong signatures in the spectrum of the resulting CR proton fluxes.

Keywords: Galactic cosmic rays, Shocks, Supernova remnants