Sazuna/UAT_keywords huggingface dataset:
The TRENDS High-contrast Imaging Survey. VIII. Compendium of Benchmark Objects. The physical properties of faint stellar and substellar objects often rely on indirect, model-dependent estimates. For example, the masses of brown dwarfs are usually inferred using evolutionary models, which are age dependent and have yet to be properly calibrated. With the goal of identifying new benchmark objects to test low-mass stellar and substellar models, we have carried out a comprehensive adaptive optics survey as part of the TaRgetting bENchmark-objects with the Doppler Spectroscopy high-contrast imaging program. Using legacy radial velocity measurements from the High Resolution Echelle Spectrometer at Keck, we have identified several dozen stars that show long-term Doppler accelerations. We present follow-up high-contrast observations from the campaign and report the discovery of 31 comoving companions, as well as 11 strong candidate companions, to solar-type stars with well-determined parallax and metallicity values. Benchmark objects of this nature lend themselves to orbit determinations, dynamical mass estimates, and independent compositional assessment. This compendium of benchmark objects will serve as a convenient test group to substantiate theoretical evolutionary and atmospheric models near the hydrogen fusing limit.

Keywords: Brown dwarfs, Binary stars, M stars, Spectroscopic binary stars, Astrometric binary stars, Direct imaging, Low mass stars, Radial velocity, Visual binary stars
Estimation of the Physical Parameters of a CME at High Coronal Heights Using Low-frequency Radio Observations. Measuring the physical parameters of coronal mass ejections (CMEs), particularly their entrained magnetic field, is crucial for understanding their physics and for assessing their geoeffectiveness. At the moment, only remote sensing techniques can probe these quantities in the corona, the region where CMEs form and acquire their defining characteristics. Radio observations offer the most direct means for estimating the magnetic field when gyrosynchrotron emission is detected. In this work we measure various CME plasma parameters, including its magnetic field, by modeling the gyrosynchrotron emission from a CME. The dense spectral coverage over a wide frequency range provided by the Murchison Widefield Array (MWA) affords a much better spectral sampling than possible before. The MWA images also provide a much higher imaging dynamic range, enabling us to image these weak emissions. Hence we are able to detect radio emission from a CME at larger distances (∼4.73 R⊙) than have been reported before. The flux densities reported here are among the lowest measured in similar works. Our ability to make extensive measurements on a slow and otherwise unremarkable CME suggests that with the availability of data from the new-generation instruments like the MWA, it should now be possible to make routine, direct detections of radio counterparts of CMEs.

Keywords: Solar magnetic fields, Solar coronal mass ejections, Active sun
Cosmic-Ray-driven Outflows from the Large Magellanic Cloud: Contributions to the LMC Filament. In this paper, we build from previous work and present simulations of recent (within the past Gyr), magnetized, cosmic-ray driven outflows from the Large Magellanic Cloud (LMC), including our first attempts to explicitly use the derived star formation history of the LMC to seed outflow generation. We run a parameter set of simulations for different LMC gas masses and cosmic-ray transport treatments, and we make preliminary comparisons to published outflow flux estimates, neutral and ionized hydrogen observations, and Faraday rotation measure maps. We additionally report on the gas mass that becomes unbound from the LMC disk and swept by ram pressure into the Trailing Magellanic Stream. We find that, even for our largest outburst, the mass contribution to the Stream is still quite small, as much of the outflow-turned-halo gas is shielded on the LMCs far-side due to the LMCs primarily face-on infall through the Milky Way halo over the past Gyr. On the LMC's near-side, past outflows have fought an uphill battle against ram pressure, with the near-side halo mass being at least a factor of a few smaller than that of the far-side. Absorption-line studies probing only the LMC foreground, then, may be severely underestimating the total mass of the LMC halo formed by outflows.

Keywords: Galactic winds, Large Magellanic Cloud, Magellanic Stream, Magnetic fields, Cosmic rays
Studying the Reflection Spectra of the New Black Hole X-Ray Binary Candidate MAXI J1631-479 Observed by NuSTAR: A Variable Broad Iron Line Profile. We present results from the Nuclear Spectroscopic Telescope Array observations of the new black hole X-ray binary candidate MAXI J1631-479 at two epochs during its 2018-2019 outburst, which caught the source in a disk dominant state and a power-law dominant state. Strong relativistic disk reflection features are clearly detected, displaying significant variations in the shape and strength of the broad iron emission line between the two states. Spectral modeling of the reflection spectra reveals that the inner radius of the optically thick accretion disk evolves from &lt;1.9 ${r}_{{\rm{g}}}$ to 12 ± 1 rg (statistical errors at 90% confidence level) from the disk dominant to the power-law dominant state. Assuming in the former case that the inner disk radius is consistent with being at the innermost stable circular orbit, we estimate a black hole spin of a* &gt; 0.94. Given that the bolometric luminosity is similar in the two states, our results indicate that the disk truncation observed in MAXI J1631-479 in the power-law dominant state is unlikely to be driven by a global variation in the accretion rate. We propose that it may instead arise from local instabilities in the inner edge of the accretion disk at high accretion rates. In addition, we find an absorption feature in the spectra centered at 7.33 ± 0.03 keV during the disk dominant state, which is evidence for the rare case that an extremely fast disk wind ( ${V}_{\mathrm{out}}={0.067}_{-0.004}^{+0.001}\,c$ ) is observed in a low-inclination black hole binary, with the viewing angle of 29° ± 1° as determined by the reflection modeling.

Keywords: Accretion, Black hole physics, X-ray transient sources, X-ray binary stars
The Galactic Center Black Hole, Sgr A*, as a Probe of New Gravitational Physics with the Scalaron Fifth Force. The Galactic Center black hole (Sgr A*) provides an ideal laboratory for astronomical tests of new gravitational physics. This work reports that curvature correction (f(R)) to quantum vacuum fluctuations naturally yields a Yukawa-type scalar fifth force with potential $\exp \left(-{M}_{\psi }r\right)/r$ , where Mψ is the mass of the f(R) scalarons. Estimating the UV and IR cutoff scales of vacuum fluctuations, the Yukawa coupling strength is connected to the scalaron field amplitude. Whereas recently constrained Yukawa coupling and range correspond to light scalarons with Mψ = (1.37 × 10-21-5.49 × 10-20) eV, vacuum fluctuations yield a massive scalaron with Mψ = 10-16 eV. Scalaron-induced periastron shift of stellar orbits near Sgr A* has been studied with respect to the semimajor axis in the range a = 10-1000 au. It is found that the scalarons resulting from quantum fluctuations affect the precession of orbits with a = 128-256 Rs. The possibility of future constraints on massive scalarons in observations near Sgr A* is discussed. This is a new and independent effort to express a prototype quantum gravity effect in terms of astronomically accessible quantities.

Keywords: Gravitation, Galactic center
Molecular Clumps Disguising Their Star Formation Efficiency per Free-fall Time: What We Can Do Not to Be Fooled. The presence of a volume-density gradient in molecular clumps allows them to raise their star formation rate compared with what they would experience if their gas were uniform in density. This higher value for the star formation rate yields in turn a higher star formation efficiency per free-fall time that we measure. The measured star formation efficiency per free-fall time, ${\epsilon }_{\mathrm{ff},\mathrm{meas}}$ , of clumps is therefore plagued by a degeneracy, as two factors contribute to it: one is the density gradient of the clump gas, the other is the intrinsic star formation efficiency per free-fall time, ${\epsilon }_{\mathrm{ff},\mathrm{int}}$ , with which the clump would form stars should there be no gas-density gradient. This paper presents a method allowing one to recover the intrinsic efficiency of a centrally concentrated clump. It hinges on the relation between the surface densities in stars and gas measured locally from clump center to clump edge. Knowledge of the initial density profile of the clump gas is not required. A step-by-step description of the method is provided as a tool in hand for observers. Once ${\epsilon }_{\mathrm{ff},\mathrm{int}}$ has been estimated, it can be compared with its measured, clump-averaged, counterpart, ${\epsilon }_{\mathrm{ff},\mathrm{meas}}$ , to quantify the impact that the initial gas-density profile of a clump has had on its star formation history.

Keywords: Star formation, Molecular clouds, Star clusters
ALMA Polarimetry Measures Magnetically Aligned Dust Grains in the Torus of NGC 1068. The obscuring structure surrounding active galactic nuclei (AGN) can be explained as a dust and gas flow cycle that fundamentally connects the AGN with their host galaxies. This structure is believed to be associated with dusty winds driven by radiation pressure. However, the role of magnetic fields, which are invoked in almost all models for accretion onto a supermassive black hole and outflows, has not been thoroughly studied. Here we report the first detection of polarized thermal emission by means of magnetically aligned dust grains in the dusty torus of NGC 1068 using ALMA Cycle 4 polarimetric dust continuum observations (0"07, 4.2 pc; 348.5 GHz, 860 μm). The polarized torus has an asymmetric variation across the equatorial axis with a peak polarization of 3.7% ± 0.5% and position angle of 109° ± 2° (B-vector) at ∼8 pc east from the core. We compute synthetic polarimetric observations of magnetically aligned dust grains assuming a toroidal magnetic field and homogeneous grain alignment. We conclude that the measured 860 μm continuum polarization arises from magnetically aligned dust grains in an optically thin region of the torus. The asymmetric polarization across the equatorial axis of the torus arises from (1) an inhomogeneous optical depth and (2) a variation of the velocity dispersion, I.e., a variation of the magnetic field turbulence at subparsec scales, from the eastern to the western region of the torus. These observations and modeling constrain the torus properties beyond spectral energy distribution results. This study strongly supports that magnetic fields up to a few parsecs contribute to the accretion flow onto the active nuclei.

Keywords: Seyfert galaxies, Active galactic nuclei, Extragalactic astronomy, Submillimeter astronomy, Polarimetry, Extragalactic magnetic fields
Plasma Diagnostics from Active Region and Quiet-Sun Spectra Observed by Hinode/EIS: Quantifying the Departures from a Maxwellian Distribution. We perform plasma diagnostics, including that of the non-Maxwellian κ-distributions, in several structures observed in the solar corona by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. To prevent uncertainties due to the in-flight calibration of EIS, we selected spectral atlases observed shortly after the launch of the mission. One spectral atlas contains an observation of an active region, while the other is an off-limb quiet-Sun region. To minimize the uncertainties of the diagnostics, we rely only on strong lines and average the signal over a spatial area within selected structures. Multiple plasma parameters are diagnosed, such as the electron density, the differential emission measure, and the non-Maxwellian parameter κ. To do that, we use a simple, well-converging iterative scheme based on refining the initial density estimates via the differential emission measure (DEM) and κ. We find that while the quiet-Sun spectra are consistent with a Maxwellian distribution, the coronal loops and moss observed within the active region are strongly non-Maxwellian with κ ⪅ 3. These results were checked by calculating synthetic ratios using DEMs obtained as a function of κ. Ratios predicted using the DEMs assuming κ-distributions converged to the ratios observed in the quiet Sun and coronal loops. To our knowledge, this work presents a strong evidence of the presence of different electron distributions between two physically distinct parts of the solar corona.

Keywords: Non-thermal radiation sources, Solar corona, Solar extreme ultraviolet emission, Spectroscopy
Black Hole Coagulation: Modeling Hierarchical Mergers in Black Hole Populations. Data from the Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo detectors have confirmed that stellar-mass black holes can merge within a Hubble time, leaving behind massive remnant black holes. In some astrophysical environments such as globular clusters and active galactic nucleus disks, it may be possible for these remnants to take part in further compact-object mergers, producing a population of hierarchically formed black holes. In this work, we present a parameterized framework for describing the population of binary black hole (BBH) mergers, while self-consistently accounting for hierarchical mergers. The framework casts black holes as particles in a box that can collide based on an effective cross section, but allows inputs from more detailed astrophysical simulations. Our approach is relevant to any population that is comprised of second- or higher-generation black holes, such as primordial black holes or dense cluster environments. We describe some possible inputs to this generic model and their effects on the black hole merger populations and use the model to perform Bayesian inference on the catalog of black holes from LIGO and Virgo's first two observing runs. We find that models with a high rate of hierarchical mergers are disfavored, consistent with previous population analyses. Future gravitational-wave events will further constrain the inputs to this generic hierarchical merger model, enabling a deeper look into the formation environments of BBHs.

Keywords: Gravitational waves, Compact binary stars, Black holes
Reinflation of Warm and Hot Jupiters. Understanding the anomalous radii of many transiting hot gas-giant planets is a fundamental problem of planetary science. Recent detections of reinflated warm Jupiters orbiting post-main-sequence stars and the reinflation of hot Jupiters while their host stars evolve on the main sequence may help constrain models for the anomalous radii of hot Jupiters. In this work, we present evolution models studying the reinflation of gas giants to determine how varying the depth and intensity of deposited heating affects both main-sequence reinflation of hot Jupiters and post-main-sequence reinflation of warm Jupiters. We find that deeper heating is required to reinflate hot Jupiters than is needed to suppress their cooling, and that the timescale of reinflation decreases with increasing heating rate and depth. We find a strong degeneracy between heating rate and depth, with either strong shallow heating or weak deep heating providing an explanation for main-sequence reinflation of hot Jupiters. This degeneracy between heating rate and depth can be broken in the case of post-main-sequence reinflation of warm Jupiters, as the inflation must be rapid to occur within post-main-sequence evolution timescales. We also show that the dependence of heating rate on the incident stellar flux inferred from the sample of hot Jupiters can explain reinflation of both warm and hot Jupiters. TESS will obtain a large sample of warm Jupiters orbiting post-main-sequence stars, which will help to constrain the mechanism(s) causing the anomalous radii of gas-giant planets.

Keywords: Hot Jupiters, Exoplanet evolution, Planetary interior, Extrasolar gaseous giant planets, Planetary structure, Stellar evolution
Fluorine in the Solar Neighborhood: The Need for Several Cosmic Sources. The cosmic origin of fluorine is still not well constrained. Several nucleosynthetic channels at different phases of stellar evolution have been suggested, but these must be constrained by observations. For this, the fluorine abundance trend with metallicity spanning a wide range is required. Our aim is to determine stellar abundances of fluorine for $-1.1\lt [\mathrm{Fe}/{\rm{H}}]\lt +0.4$ . We determine the abundances from HF lines in infrared K-band spectra ( $\sim 2.3\,\mu {\rm{m}}$ ) of cool giants, observed with the IGRINS and Phoenix high-resolution spectrographs. We derive accurate stellar parameters for all our observed K giants, which is important as the HF lines are very temperature-sensitive. We find that [F/Fe] is flat as a function of metallicity at [F/Fe]∼0, but increases as the metallicity increases. The fluorine slope shows a clear secondary behavior in this metallicity range. We also find that the [F/Ce] ratio is relatively flat for $-0.6\lt [\mathrm{Fe}/{\rm{H}}]\lt 0$ , and that for two metal-poor ( $[\mathrm{Fe}/{\rm{H}}]\lt -0.8$ ), s-process element-enhanced giants, we do not detect an elevated fluorine abundance. We interpret all of these observational constraints as indications that several major processes are at play for the cosmic budget of fluorine over time: from those in massive stars at low metallicities, through the asymptotic giant branch star contribution at $-0.6\lt [\mathrm{Fe}/{\rm{H}}]\lt 0$ , to processes with increasing yields with metallicity at supersolar metallicities. The origins of the latter, and whether or not Wolf-Rayet stars and/or novae could contribute at supersolar metallicities, is currently not known. To quantify these observational results, theoretical modeling is required. More observations in the metal-poor region are required to clarify the processes there.

Keywords: High resolution spectroscopy, Cosmic abundances, Stellar abundances, Chemical abundances, Infrared astronomy
Constraining Short Gamma-Ray Burst Jet Properties with Gravitational Waves and Gamma-Rays. Gamma-ray burst (GRB) prompt emission is highly beamed, and understanding the jet geometry and beaming configuration can provide information on the poorly understood central engine and circumburst environment. Prior to the advent of gravitational-wave astronomy, astronomers relied on observations of jet breaks in the multiwavelength afterglow to determine the GRB opening angle, since the observer's viewing angle relative to the system cannot be determined from the electromagnetic data alone. Gravitational-wave observations, however, provide an independent measurement of the viewing angle. We describe a Bayesian method for determining the geometry of short GRBs (sGRBs) using coincident electromagnetic and gravitational-wave observations. We demonstrate how an ensemble of multimessenger detections can be used to measure the distributions of the jet energy, opening angle, Lorentz factor, and angular profile of sGRBs; we find that for a population of 100 such observations, we can constrain the mean of the opening angle distribution to within 10° regardless of the angular emission profile. Conversely, the constraint on the energy distribution depends on the shape of the profile, which can be distinguished.

Keywords: Neutron stars, Gamma-ray bursts, Relativistic jets, Compact binary stars, Gravitational wave sources, Gravitational wave astronomy, Gravitational waves, Compact objects, Gamma-ray transient sources
The Composite X-Ray Spectrum of 3CRR Quasars. The reason for the difference between the composite X-ray spectrum for radio-loud quasars (RLQs) versus radio-quiet quasars (RQQs) is still unclear. To study this difference, we built a new composite X-ray spectrum of RLQs using Chandra X-ray data and Sloan Digital Sky Survey optical data for the sample of 3CRR quasars. We find the X-ray spectra of all 3CRR quasars, except for 3C 351, have no soft X-ray excess and can be fitted well with an absorbed power-law model. Our composite X-ray spectrum is similar to that of Shang et al. for RLQs, showing higher hard X-ray and lower soft X-ray flux than the composite X-ray spectrum of RQQs. Most blazar-like 3CRR quasars have higher X-ray flux than the median composite X-ray spectrum, which could be related to the contribution of beamed jet emission at X-ray band. From the literature, we find that nineteen 3CRR quasars have extended X-ray emission related to radio jets, indicating the inevitable contribution of jets at X-ray band. In contrast to RQQs, the X-ray photon index of 3CRR quasars does not correlate with the Eddington ratio. Our results suggest that the jet emission at X-ray band in RLQs could be related to the difference in composite X-ray spectrum between RLQs and RQQs.

Keywords: Quasars, Radio loud quasars, X-ray quasars, Spectral energy distribution, Catalogs
Quasiperiodic Velocity Fluctuations in Eruptive Prominences Observed by AIA/SDO. The current study presents an investigation of the behavior of prominences during eruptions. Variations in the distribution of their velocities are detected at altitudes &lt;0.6 R⊙. Detailed analyses are carried out for 304 Å Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. To track the behavior of prominences during eruptions, 41 events in the period 2010-2017 are studied. To follow the rise of a filament on higher altitudes (up to 32 R⊙), Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph (SOHO/LASCO) data are also inspected. They are used to obtain kinematic profiles of eruptions. Obtained height-time and speed-time plots of the eruptions show velocity fluctuations in 83% of the explored cases, detected only in the SDO/AIA field of view, and not in any of the prominences observed at higher altitudes by SOHO/LASCO. Time intervals between fluctuations and heights at which they are detected are estimated. Strong periodicity cannot be determined.

Keywords: Solar prominences, Solar filament eruptions
Leptonic or Hadronic Emission: The X-Ray Radiation Mechanism of Large-scale Jet Knots in 3C 273. A comprehensively theoretical analysis of the broadband spectral energy distributions (SEDs) of large-scale jet knots in 3C 273 is presented to reveal their X-ray radiation mechanism. We show that these SEDs cannot be explained with a single-electron population model when the Doppler boosting effect is either considered or not. By adding a more energetic electron (the leptonic model) or proton (the hadronic model) population, the SEDs of all knots are well represented. In the leptonic model, the electron population that contributes the X-ray emission is more energetic than the one responsible for the radio-optical emission by almost two orders of magnitude; the derived equipartition magnetic field strengths (Beq) are ∼0.1 mG. In the hadronic model, protons with energy ∼20 PeV are required to interpret the observed X-rays; the Beq values are several mG, larger than those in the leptonic model. Based on the fact that no resolved substructures are observed in these knots and the fast cooling time of the high-energy electrons does not easily explain the observed X-ray morphologies, we argue that the two distinct electron populations accelerated in these knots are unreasonable and their X-ray emission is attributed to the proton synchrotron radiation accelerated in these knots. In cases where these knots have relativistic motion toward the observer, the super-Eddington issue of the hadronic model can be avoided. Multiwavelength polarimetry and γ-ray observations with high resolution may be helpful to discriminate these models.

Keywords: Non-thermal radiation sources, Active galactic nuclei, Galaxy jets, X-ray active galactic nuclei