Sazuna/UAT_keywords huggingface dataset:
H1821+643: The Most X-Ray and Infrared Luminous Active Galactic Nucleus (AGN) in the Swift/BAT Survey in the Process of Rapid Stellar and Supermassive Black Hole Mass Assembly. H1821+643 is the most X-ray luminous nonbeamed active galactic nucleus (AGN) of L 14-150 keV = 5.2 × 1045 erg s-1 in the Swift/Burst Alert Telescope (BAT) ultrahard X-ray survey, and it is also a hyperluminous infrared (IR) galaxy L IR = 1013.2 L ⊙ residing in the center of a massive galaxy cluster, which is a unique environment achieving the rapid mass assembly of black holes (BH) and host galaxies in the local universe. We decompose the X-ray to IR spectral energy distribution (SED) into the AGN and starburst component using the SED-fitting tool CIGALE-2022.0 and show that H1821+643 consumes a large amount of cold gas ( ${\dot{M}}_{\mathrm{con}}$ ) with star formation rate of $\mathrm{log}(\mathrm{SFR}/{M}_{\odot }\,{\mathrm{yr}}^{-1})=3.01\pm 0.04$ and BH accretion rate of $\mathrm{log}({\dot{M}}_{\mathrm{BH}}/{M}_{\odot }\,{\mathrm{yr}}^{-1})=1.20\pm 0.05$ . This high ${\dot{M}}_{\mathrm{con}}$ is larger than the cooling rate ( ${\dot{M}}_{\mathrm{cool}}$ ) of the intracluster medium, ${\dot{M}}_{\mathrm{con}}/{\dot{M}}_{\mathrm{cool}}\gtrsim 1$ , which is 1 to 2 orders of magnitude higher than the typical value of other systems, indicating that H1821+643 provides the unique and extreme environment of rapid gas consumption. We also show that H1821+643 has an efficient cooling path achieving from 107 to 102 K thanks to [O I] 63 μm, which is a main coolant in low temperature range (104 to 102 K) with a cooling rate of ${\dot{M}}_{\mathrm{cool}}=3.2\times {10}^{5}\ {{\rm{M}}}_{\odot }\,{\mathrm{yr}}^{-1}$ , and the star-forming region extends over 40 kpc scale.

Keywords: Galaxy clusters, Supermassive black holes, Quasars, Galaxy jets, Active galactic nuclei, Galaxy evolution
The Turndown of the Baryonic Tully-Fisher Relation and Changing Baryon Fraction at Low Galaxy Masses. The ratio of baryonic-to-dark matter in present-day galaxies constrains galaxy formation theories and can be determined empirically via the baryonic Tully-Fisher relation (BTFR), which compares a galaxy's baryonic mass (M bary) to its maximum rotation velocity (V max). The BTFR is well determined at M bary &gt; 108 M ⊙, but poorly constrained at lower masses due to small samples and the challenges of measuring rotation velocities in this regime. For 25 galaxies with high-quality data and M bary ≲ 108 M ⊙, we estimate M bary from infrared and H I observations and V max from the H I gas rotation. Many of the V max values are lower limits because the velocities are still rising at the edge of the detected H I disks (R max); consequently, most of our sample has lower velocities than expected from extrapolations of the BTFR at higher masses. To estimate V max, we map each galaxy to a dark matter halo assuming density profiles with and without cores. In contrast to noncored profiles, we find the cored profile rotation curves are still rising at R max values, similar to the data. When we compare the V max values derived from the cored density profiles to our M bary measurements, we find a turndown of the BTFR at low masses that is consistent with Λ cold dark matter predictions and implies baryon fractions of 1%-10% of the cosmic value. Although we are limited by the sample size and assumptions inherent in mapping measured rotational velocities to theoretical rotation curves, our results suggest that galaxy formation efficiency drops at masses below M bary ~ 108 M ⊙, corresponding to M 200 ~ 1010 M ⊙.

Keywords: Dwarf irregular galaxies, Galaxy formation, Galaxy properties, Scaling relations, Galaxy kinematics
A Search for Lensed Lyα Emitters within the Early HETDEX Data Set. The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is a large-volume spectroscopic survey without preselection of sources, searching ~540 deg2 for Lyα emitting galaxies (LAEs) at 1.9 &lt; z &lt; 3.5. Taking advantage of such a wide-volume survey, we perform a pilot study using early HETDEX data to search for lensed Lyα emitters (LAEs). After performing a proof of concept using a previously known lensed LAE covered by HETDEX, we perform a search for previously unknown lensed LAEs in the HETDEX spectroscopic sample. We present a catalog of 26 potential LAEs lensed by foreground, red, non-star-forming galaxies at z ~ 0.4-0.7. We estimate the magnification for each candidate system, finding 12 candidates to be within the strong lensing regime (magnification μ &gt; 2). Follow-up observations of these potential lensed LAEs have the potential to confirm their lensed nature and explore these distant galaxies in more detail.

Keywords: Lyman-alpha galaxies, Gravitational lensing
LISA Gravitational Wave Sources in a Time-varying Galactic Stochastic Background. A unique challenge for data analysis with the Laser Interferometer Space Antenna (LISA) is that the noise backgrounds from instrumental noise and astrophysical sources will change significantly over both the year and the entire mission. Variations in the noise levels will be on timescales comparable to, or shorter than, the time most signals spend in the detector's sensitive band. The variation in the amplitude of the galactic stochastic GW background from galactic binaries as the antenna pattern rotates relative to the galactic center is a particularly significant component of the noise variation. LISA's sensitivity to different source classes will therefore vary as a function of sky location and time. The variation will impact both overall signal-to-noise and the efficiency of alerts to EM observers to search for multimessenger counterparts.

Keywords: Gravitational wave astronomy, Supermassive black holes, Compact binary stars, Gravitational waves
Numerical Research on the Effect of the Initial Parameters of CME Flux-rope Model on Simulation Results. III. Different Initial Energy of CMEs. In numerical studies, the initial parameters of coronal mass ejections (CMEs) have great influence on the simulation results. In our previous work, it has been proved that when the initial velocity is constant, the initial total mass mainly determines the propagation of the CME. On this basis, we carry out further research from the perspective of CME initial energy. We introduced a graduated cylindrical shell model into a 3D interplanetary total variation diminishing magnetohydrodynamic model to study the effect of different parameters of CMEs on simulation results. In this paper, we simulate several CME cases with different initial parameters and study the simulation results with a different initial energy composition. Actually, in interplanetary space, the kinetic energy of the CME always plays a dominant role. In order to study the effect of the initial thermal energy and magnetic energy on the propagation process of the CME, in this simulation, we adjust the initial parameters to make the thermal energy and magnetic energy reach the same level as the kinetic energy or an even higher level. Our results show that the initial total energy of the CME basically determines its arrival time at Earth, which indicates that the kinetic energy, thermal energy, and magnetic energy have similar effects on the propagation of the CMEs. Moreover, when the total energy keeps constant, the decrease of initial density will lead to the enhancement of CME expansion, which may make the front of the CME reach Earth earlier.

Keywords: Space weather, Solar coronal mass ejections, Magnetohydrodynamical simulations
The Active Chromospheres of Lithium-rich Red Giant Stars. We have gathered near-infrared zyJ-band high-resolution spectra of nearly 300 field red giant stars with known lithium abundances in order to survey their He I λ10830 absorption strengths. This transition is an indicator of chromospheric activity and/or mass loss in red giants. The majority of stars in our sample reside in the red clump or red horizontal branch based on their V - J, M  V  color-magnitude diagram, and Gaia T eff and log(g) values. Most of our target stars are Li-poor in the sense of having normally low Li abundances, defined here as log ϵ(Li) &lt; 1.25. Over 90% of these Li-poor stars have weak λ10830 features. However, more than half of the 83 Li-rich stars (log ϵ(Li) &gt; 1.25) have strong λ10830 absorptions. These large λ10830 lines signal excess chromospheric activity in Li-rich stars; there is almost no indication of significant mass loss. The Li-rich giants may also have a higher binary fraction than Li-poor stars, based on their astrometric data. It appears likely that both residence on the horizontal branch and present or past binary interaction play roles in the significant Li-He connection established in this survey. * Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Keywords: Stellar abundances, Stellar chromospheres, Red giant stars, Stellar photospheres, Stellar spectral lines
Modeling Redshift-space Clustering with Abundance Matching. We explore the degrees of freedom required to jointly fit projected and redshift-space clustering of galaxies selected in three bins of stellar mass from the Sloan Digital Sky Survey Main Galaxy Sample (SDSS MGS) using a subhalo abundance matching (SHAM) model. We employ emulators for relevant clustering statistics in order to facilitate our analysis, leading to large speed gains with minimal loss of accuracy. We are able to simultaneously fit the projected and redshift-space clustering of the two most massive galaxy samples that we consider with just two free parameters: scatter in stellar mass at fixed SHAM proxy, and the dependence of the SHAM proxy on dark matter halo concentration. We find some evidence for models that include velocity bias, but including orphan galaxies improves our fits to the lower-mass samples significantly. We also model the clustering signals of specific star formation rate (sSFR) selected samples using conditional abundance matching (CAM). We obtain acceptable fits to projected and redshift-space clustering as a function of sSFR and stellar mass using two CAM variants, although the fits are worse than for stellar-mass-selected samples alone. By incorporating nonunity correlations between the CAM proxy and sSFR, we are able to resolve previously identified discrepancies between CAM predictions and SDSS observations of the environmental dependence of quenching for isolated central galaxies.

Keywords: Cosmology, Large-scale structure of the universe, Astrostatistics techniques, Galaxy quenching, N-body simulations
Xenon in the Protoplanetary Disk (PPD), in Two Planets, and a Comet. Isotopic anomalies in several elements, as recently observed in meteorites, are generally interpreted to indicate nonequilibrium environments in the protoplanetary disk (PPD). Here we study reported Xe isotopic compositions on planets Earth and Mars, in a comet, and in meteorites for precursor discrepancies. Abundance variations of inferred presolar nano-diamonds, the carrier phase of the Xe-HL component, appear to be the primary source of nonuniformity of Xe precursors in the PPD, together with mechanisms of mass-dependent fractionation. While planet Mars kept a record of initial solar Xe isotopic abundances, such a record is missing for planet Earth. Xe isotopic abundances in paleo-atmospheres of both planets represent secondary reservoirs that show mass-dependent fractionation effects, but the inferred compositions of their PPD precursors differ: Mars atmospheric precursor Xe had solar isotopic composition, while Earth's Xe precursor is consistent with a PPD reservoir of low nano-diamond abundance. Strong mass-dependent fractionation effects are observed in Xe components of IAB irons and in Yamato carbonaceous (CY) chondrites, and show that fractionation mechanisms are not restricted to planetary atmospheres. These records show that Xe isotopes in solar system reservoirs are useful tracers of evolutionary processes and of nonequilibrated presolar components in the PPD.

Keywords: Solar system formation, Planetary atmospheres, Solar system terrestrial planets, Planetary science
A Milliarcsecond-accurate Position for Sagittarius A*. The absolute position of Sgr A*, the compact radio source at the center of the Milky Way, had been uncertain by several tens of milliarcseconds. Here we report improved astrometric measurements of the absolute position and proper motion of Sgr A*. Three epochs of phase-referencing observations were conducted with the Very Long Baseline Array for Sgr A* at 22 and 43 GHz in 2019 and 2020. Using extragalactic radio sources with submilliarcsecond-accurate positions as reference, we determined the absolute position of Sgr A* at a reference epoch 2020.0 to be at α(J2000) = 17h45m40.ˢ032863 ± 0.ˢ000016 and δ(J2000) = - $29^\circ 00^{\prime} 28\buildrel{\prime\prime}\over{.} 24260\,\pm \,$ 0.″00047, with an updated proper motion -3.152 ± 0.011 and -5.586 ± 0.006 mas yr-1 in the easterly and northerly directions, respectively.

Keywords: Supermassive black holes, Astrometry
The Instantaneous Redshift Difference of Gravitationally Lensed Images: Theory and Observational Prospects. Due to the expansion of our universe, the redshift of distant objects changes with time. Although the amplitude of this redshift drift is small, it will be measurable with decade-long campaigns by the next generation of telescopes. Here we present an alternative view of the redshift drift which captures the expansion of the universe in single-epoch observations of the multiple images of gravitationally lensed sources. Considering a sufficiently massive lens, with an associated time delay of order decades, simultaneous photons arriving at a detector would have been emitted decades earlier in one image compared to another, leading to an instantaneous redshift difference between the images. We also investigated the peculiar velocity which may influence the redshift difference in observation. While still requiring the observational power of the next generation of telescopes and instruments, the advantage of such a single-epoch detection over other redshift drift measurements is that it will be less susceptible to systematic effects that result from requiring instrument stability over decade-long campaigns.

Keywords: Cosmology, Strong gravitational lensing
Constraining the Origin of Stellar Binary Black Hole Mergers by Detections of Their Lensed Host Galaxies and Gravitational Wave Signals. A significant number of stellar binary black hole (sBBH) mergers may be lensed and detected by the third generation of gravitational wave (GW) detectors. Their lensed host galaxies may be detectable, which would thus help to accurately localize these sources and provide a new approach to study the origin of sBBHs. In this paper, we investigate the detectability of lensed host galaxies for lensed sBBH mergers. We find that the detection fraction of galaxies hosting lensed GW events can be significantly different for a survey with a given limiting magnitude if sBBHs are produced by different mechanisms, such as the evolution of massive binary stars, dynamical interactions in dense star clusters, and production assisted by active galactic nuclei or massive black holes. Furthermore, we illustrate that the statistical spatial distributions of those lensed sBBHs in their hosts resulting from different sBBH formation channels can differ. Therefore, with the third generation of GW detectors and future large-scale galaxy surveys, it is possible to independently constrain the origin of sBBHs via the detection fraction of those lensed events with identifiable lensing host signatures and/or even to constrain the fractional contributions from different sBBH formation mechanisms.

Keywords: Black holes, Gravitational wave sources, Gravitational wave astronomy, Gravitational lensing, Galaxies
Mode Mixing and Rotational Splittings. I. Near-degeneracy Effects Revisited. Rotation is typically assumed to induce strictly symmetric rotational splitting into the rotational multiplets of pure p- and g-modes. However, for evolved stars exhibiting mixed modes, avoided crossings between different multiplet components are known to yield asymmetric rotational splitting, in particular for near-degenerate mixed-mode pairs, where notional pure p-modes are fortuitously in resonance with pure g-modes. These near-degeneracy effects have been described in subgiants, but their consequences for the characterization of internal rotation in red giants have not previously been investigated in detail, in part owing to theoretical intractability. We employ new developments in the analytic theory of mixed-mode coupling to study these near-resonance phenomena. In the vicinity of the most p-dominated mixed modes, the near-degenerate intrinsic asymmetry from pure rotational splitting increases dramatically over the course of stellar evolution, and it depends strongly on the mode-mixing fraction ζ. We also find that a linear treatment of rotation remains viable for describing the underlying p- and g-modes, even when it does not for the resulting mixed modes undergoing these avoided crossings. We explore observational consequences for potential measurements of asymmetric mixed-mode splitting, which has been proposed as a magnetic-field diagnostic. Finally, we propose improved measurement techniques for rotational characterization, exploiting the linearity of rotational effects on the underlying p/g-modes, while still accounting for these mixed-mode coupling effects.

Keywords: Theoretical techniques, Stellar magnetic fields, Computational methods, Stellar rotation, Asteroseismology
Perfecting Our Set of Spectrophotometric Standard DA White Dwarfs. We verified for photometric stability a set of DA white dwarfs with Hubble Space Telescope magnitudes from the near-ultraviolet to the near-infrared and ground-based spectroscopy by using time-spaced observations from the Las Cumbres Observatory network of telescopes. The initial list of 38 stars was whittled to 32 final ones, which comprise a high-quality set of spectrophotometric standards. These stars are homogeneously distributed around the sky and are all fainter than r ~ 16.5 mag. Their distribution is such that at least two of them would be available to be observed from any observatory on the ground at any time at airmass less than 2. Light curves and different variability indices from the Las Cumbres Observatory data were used to determine the stability of the candidate standards. When available, Pan-STARRS1, Zwicky Transient Facility, and TESS data were also used to confirm the star classification. Our analysis showed that four DA white dwarfs may exhibit evidence of photometric variability, while a fifth is cooler than our established lower temperature limit, and a sixth star might be a binary. In some instances, due to the presence of faint nearby red sources, care should be used when observing a few of the spectrophotometric standards with ground-based telescopes. Light curves and finding charts for all the stars are provided.

Keywords: White dwarf stars, Flux calibration, Photometric standard stars, DA stars, Spectrophotometric standards, Variable stars, Time series analysis
Active Galactic Nuclei Continuum Reverberation Mapping Based on Zwicky Transient Facility Light Curves. We perform a systematic survey of active galactic nuclei (AGNs) continuum lags using ~3 days cadence gri-band light curves from the Zwicky Transient Facility. We select a sample of 94 type 1 AGNs at z &lt; 0.8 with significant and consistent inter-band lags based on the interpolated cross-correlation function method and the Bayesian method JAVELIN. Within the framework of the "lamp-post" reprocessing model, our findings are: (1) The continuum emission (CE) sizes inferred from the data are larger than the disk sizes predicted by the standard thin-disk model. (2) For a subset of the sample, the CE size exceeds the theoretical limit of the self-gravity radius (12 lt-days) for geometrically thin disks. (3) The CE size scales with continuum luminosity as R CE ∝ L 0.48±0.04 with a scatter of 0.2 dex, analogous to the well-known radius-luminosity relation of broad Hβ. These findings suggest a significant contribution of diffuse continuum emission from the broad-line region (BLR) to AGN continuum lags. We find that the R CE-L relation can be explained by a photoionization model that assumes ~23% of the total flux comes from the diffuse BLR emission. In addition, the ratio of the CE size and model-predicted disk size anticorrelates with the continuum luminosity, which is indicative of a potential nondisk BLR lag contribution evolving with the luminosity. Finally, a robust positive correlation between the CE size and black hole mass is detected.

Keywords: Black hole physics, Reverberation mapping, Active galaxies
Change of Rankine-Hugoniot Relations during Postshock Relaxation of Anisotropic Distributions. Collisionless shocks channel the energy of the directed plasma flow into the heating of the plasma species and magnetic field enhancement. The kinetic processes at the shock transition cause the ion distributions just behind the shock to be nongyrotropic. Gyrotropization and subsequent isotropization occur at different spatial scales. Accordingly, for a given upstream plasma and magnetic field state, there would be different downstream states corresponding to the anisotropic and isotropic regions. Thus, at least two sets of Rankine-Hugoniot relations are needed, in general, to describe the connection of the downstream measurable parameters to the upstream ones. We establish the relation between the two sets.

Keywords: Shocks, Interplanetary shocks, Planetary bow shocks
Charting Galactic Accelerations with Stellar Streams and Machine Learning. We present a data-driven method for reconstructing the galactic acceleration field from phase-space (position and velocity) measurements of stellar streams. Our approach is based on a flexible and differentiable fit to the stream in phase-space, enabling a direct estimate of the acceleration vector along the stream. Reconstruction of the local acceleration field can be applied independently to each of several streams, allowing us to sample the acceleration field due to the underlying galactic potential across a range of scales. Our approach is methodologically different from previous works, as a model for the gravitational potential does not need to be adopted beforehand. Instead, our flexible neural-network-based model treats the stream as a collection of orbits with a locally similar mixture of energies, rather than assuming that the stream delineates a single stellar orbit. Accordingly, our approach allows for distinct regions of the stream to have different mean energies, as is the case for real stellar streams. Once the acceleration vector is sampled along the stream, standard analytic models for the galactic potential can then be rapidly constrained. We find our method recovers the correct parameters for a ground-truth triaxial logarithmic halo potential when applied to simulated stellar streams. Alternatively, we demonstrate that a flexible potential can be constrained with a neural network, and standard multipole expansions can also be constrained. Our approach is applicable to simple and complicated gravitational potentials alike and enables potential reconstruction from a fully data-driven standpoint using measurements of slowly phase-mixing tidal debris.

Keywords: Milky Way dark matter halo, Stellar streams, Galaxy dynamics, Galaxy structure, Galaxy stellar halos, Galaxy mass distribution