Sazuna/UAT_keywords huggingface dataset:
A Black Hole Feedback Valve in Massive Galaxies. Star formation in the universe's most massive galaxies proceeds furiously early in time but then nearly ceases. Plenty of hot gas remains available but does not cool and condense into star-forming clouds. Active galactic nuclei (AGNs) release enough energy to inhibit cooling of the hot gas, but energetic arguments alone do not explain why quenching of star formation is most effective in high-mass galaxies. In fact, optical observations show that quenching is more closely related to a galaxy's central stellar velocity dispersion (σv) than to any other characteristic. Here we show that high σv is critical to quenching because a deep central potential well maximizes the efficacy of AGN feedback. In order to remain quenched, a galaxy must continually sweep out the gas ejected from its aging stars. Supernova heating can accomplish this task as long as the AGN sufficiently reduces the gas pressure of the surrounding circumgalactic medium (CGM). We find that CGM pressure acts as the control knob on a valve that regulates AGN feedback and suggest that feedback power self-adjusts so that it suffices to lift the CGM out of the galaxy's potential well. Supernova heating then drives a galactic outflow that remains homogeneous if ${\sigma }_{v}\gtrsim 240\,\mathrm{km}\,{{\rm{s}}}^{-1}$ . The AGN feedback can effectively quench galaxies with a comparable velocity dispersion, but feedback in galaxies with a much lower velocity dispersion tends to result in convective circulation and accumulation of multiphase gas within the galaxy.

Keywords: X-ray astronomy, Quenched galaxies, Circumgalactic medium, Giant elliptical galaxies, Red sequence galaxies, Elliptical galaxies, Early-type galaxies
Testing the Cosmic Opacity at Higher Redshifts: Implication from Quasars with Available UV and X-Ray Observations. In this paper, we present a cosmological model-independent test for the cosmic opacity at high redshifts (z ∼ 5). We achieve this with the opacity-dependent luminosity distances derived from the nonlinear relation between X-ray and UV emissions of quasars, combined with two types of opacity-independent luminosity distances derived from the Hubble parameter measurements and simulated gravitational wave (GW) events achievable with the Einstein Telescope (ET). In the framework of two phenomenological parameterizations adopted to describe cosmic opacity at high redshifts, our main results show that a transparent universe is supported by the current observational data at a 2σ confidence level. However, the derived value of the cosmic opacity is slightly sensitive to the parameterization of τ(z), which highlights the importance of choosing a reliable parameterization to describe the optical depth τ(z) in the early universe. Compared with previous works, the combination of the quasar data and the H(z)/GW observations in similar redshift ranges provides a novel way to confirm a transparent universe (ɛ = 0 at higher redshifts z ∼ 5), with an accuracy of Δɛ ∼ 10-2. More importantly, our findings indicate that a strong degeneracy between the cosmic-opacity parameter and the parameters characterizing the LUV - LX relation of quasars, which reinforces the necessity of proper calibration for this new type of high-redshift standard candle (in a cosmological model-independent way).

Keywords: Cosmological parameters, Quasars
Dynamics of the Parker-Jeans Instability of Gaseous Disks Including the Effect of Cosmic Rays. The effect of cosmic rays on the Parker-Jeans instability in magnetized self-gravitating gaseous disks is studied using three-dimensional magnetohydrodynamic simulations with cosmic rays taken as a massless fluid with notable pressure. Cosmic-ray diffusion along the magnetic field is taken into account in the simulation. The initial configuration of the disk is a magnetized cold gas slab sandwiched between hot coronae (on top and bottom). We show that cosmic rays play an important role in the formation of filaments or clumps in some parameter regimes. In a certain range of the thickness of the gas slab, the cosmic-ray diffusion coefficient plays a decisive role in determining whether the filaments lie along or perpendicular to the magnetic field. We also consider the effect of rotation on the system.

Keywords: Magnetohydrodynamical simulations, Collapsing clouds, Interstellar clouds, Magnetic fields, Cosmic rays
The Sloan Digital Sky Survey Reverberation Mapping Project: The Hβ Radius-Luminosity Relation. Results from a few decades of reverberation mapping (RM) studies have revealed a correlation between the radius of the broad-line emitting region (BLR) and the continuum luminosity of active galactic nuclei. This "radius-luminosity" relation enables survey-scale black hole mass estimates across cosmic time, using relatively inexpensive single-epoch spectroscopy, rather than intensive RM time monitoring. However, recent results from newer RM campaigns challenge this widely used paradigm, reporting quasar BLR sizes that differ significantly from the previously established radius-luminosity relation. Using simulations of the radius-luminosity relation with the observational parameters of the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, we find that this difference is not likely due to observational biases. Instead, it appears that previous RM samples were biased to a subset of quasar properties, and the broader parameter space occupied by the SDSS-RM quasar sample has a genuinely wider range of BLR sizes. We examine the correlation between the deviations from the radius-luminosity relation and several quasar parameters; the most significant correlations indicate that the deviations depend on the UV/optical spectral energy distribution and the relative amount of ionizing radiation. Our results indicate that single-epoch black hole mass estimates that do not account for the diversity of quasars in the radius-luminosity relation could be overestimated by an average of ∼0.3 dex.

Keywords: Supermassive black holes, Active galaxies, Quasars, Galaxy nuclei
The Electromagnetic Signature of Outward Propagating Ion-scale Waves. First results from the Parker Solar Probe (PSP) mission have revealed ubiquitous coherent ion-scale waves in the inner heliosphere, which are signatures of kinetic wave-particle interactions and fluid instabilities. However, initial studies of the circularly polarized ion-scale waves observed by PSP have only thoroughly analyzed magnetic field signatures, precluding a determination of solar wind frame propagation direction and intrinsic wave polarization. A comprehensive determination of wave properties requires measurements of both electric and magnetic fields. Here, we use full capabilities of the PSP/FIELDS instrument suite to measure both the electric and magnetic components of circularly polarized waves. Comparing spacecraft frame magnetic field measurements with the Doppler-shifted cold plasma dispersion relation for parallel transverse waves constrains allowable plasma frame polarizations and wavevectors. We demonstrate that the Doppler-shifted cold plasma dispersion has a maximum spacecraft frequency ${f}_{\mathrm{sc}}^{* }$ for which intrinsically right-handed fast-magnetosonic waves propagating sunwards can appear left-handed in the spacecraft frame. Observations of left-handed waves with $| f| \gt {f}_{\mathrm{sc}}^{* }$ are uniquely explained by intrinsically left-handed, ion-cyclotron waves (ICWs). We demonstrate that electric field measurements for waves with $| f| \gt {f}_{\mathrm{sc}}^{* }$ are consistent with ICWs propagating away from the Sun, verifying the measured electric field. Applying the verified electric field measurements to the full distribution of waves suggests that, in the solar wind frame, the vast majority of waves propagate away from the Sun, indicating that the observed population of coherent ion-scale waves contains both intrinsically left- and right-hand polarized modes.

Keywords: Space plasmas, Solar wind, Plasma astrophysics, Plasma physics
A Multiwavelength Study of the γ-Ray Binary Candidate HESS J1832-093. We investigate the nature of the unidentified very-high-energy γ-ray object, HESS J1832-093, in a multiwavelength context. Based on X-ray variability and spectral index ( ${{\rm{\Gamma }}}_{X}\sim \,1.5$ ), and its broadband spectrum, which was remarkably similar to that of HESS J0632+057—a confirmed γ-ray binary—HESS J1832-093 has been considered a strong γ-ray binary candidate in previous works. In this work, we provide further evidence for this scenario. We obtained a spectrum of its IR counterpart using Gemini/Flamingo, finding absorption lines that are usually seen in massive stars, in particular O stars. We also obtained a rather steep ATCA spectrum ( $\alpha =-{1.18}_{-0.88}^{+1.04}$ ), which is consistent with a γ-ray binary. Based on spatial-spectral analysis and variability search, we found that 4FGL J1832.9-0913 is possibly associated with SNR G22.7-0.2 rather than with HESS J1832-093 only.

Keywords: Gamma-ray sources, Galactic radio sources, Massive stars, High mass x-ray binary stars, Spectroscopy
An Extremely Bright QSO at z = 2.89. We report the discovery and confirmation of a bright quasi-stellar object (QSO), 2MASS J13260399 + 7023462, at $z=2.889$ . This QSO is the first spectroscopically confirmed candidate from an ongoing search using the combination of Gaia and Wide-field Infrared Survey Explorer photometry to identify bright QSOs at z &gt; 2, the redshift regime for which the Lyα forest is accessible with ground-based facilities. With a Gaia apparent magnitude G = 16.07, 2MASS J13260399 + 7023462 is one of the brightest QSOs known at z &gt; 2, with only 15 currently known brighter QSOs. Given its inferred ${M}_{1450,\mathrm{AB}}$ magnitude and redshift, it is among the most luminous objects in the universe; the inferred black hole mass and corresponding Eddington ratio are (2.7 ± 0.4) × 1010 ${M}_{\odot }$ and 1.3 ± 0.3, respectively. Follow-up Hubble observations confirm it is not gravitationally lensed.

Keywords: Supermassive black holes, Radio quiet quasars, High-luminosity active galactic nuclei, Quasars
Common Envelope Wind Tunnel: Range of Applicability and Self-similarity in Realistic Stellar Envelopes. Common envelope evolution, the key orbital tightening phase of the traditional formation channel for close binaries, is a multistage process that presents many challenges to the establishment of a fully descriptive, predictive theoretical framework. In an approach complementary to global 3D hydrodynamical modeling, we explore the range of applicability for a simplified drag formalism that incorporates the results of local hydrodynamic "wind tunnel" simulations into a semi-analytical framework in the treatment of the common envelope dynamical inspiral phase using a library of realistic giant branch stellar models across the low, intermediate, and high-mass regimes. In terms of a small number of key dimensionless parameters, we characterize a wide range of common envelope events, revealing the broad range of applicability of the drag formalism as well its self-similar nature across mass regimes and ages. Limitations arising from global binary properties and local structural quantities are discussed together with the opportunity for a general prescriptive application for this formalism.

Keywords: Stellar interiors, Binary stars, Late stellar evolution, Close binary stars, Common envelope binary stars, Common envelope evolution, Stellar evolution
Intrinsic Morphology of Ultra-diffuse Galaxies. With the published data of apparent axis ratios for 1109 ultra-diffuse galaxies (UDGs) located in 17 low-redshift (z ∼ 0.020-0.063) galaxy clusters and 84 UDGs in two intermediate-redshift (z ∼ 0.308-0.348) clusters, we take advantage of a Markov Chain Monte Carlo approach and assume a triaxial model to investigate the intrinsic morphologies of UDGs. In contrast to the conclusion of Burkert, i.e., the underlying shapes of UDGs are purely prolate (C = B &lt; A), we find that the data favor the oblate-triaxial models (i.e., thick disks with $C\lt B\lesssim A$ ) over the nearly prolate ones. We also find that the intrinsic morphologies of UDGs are related to their stellar masses/luminosities, environments, and redshifts. First, the more luminous UDGs have puffier morphologies compared with the less luminous counterparts; the UDG morphologic dependence on luminosity is distinct from that of the typical quiescent dwarf ellipticals (dEs) and dwarf spheroidals (dSphs); in this sense, UDGs may not be simply treated as an extension of the dE/dSph class with similar evolutionary histories; they may differ not only in size. Second, the UDGs with smaller clustercentric distances are more puffed up, compared with the counterparts with larger clustercentric distances; in combination with the UDG thickness dependence on luminosity, the puffier morphologies of UDGs with high luminosities or located in the denser environments are very likely to be attributed to tidal interactions with massive galaxies. Third, we find that the intermediate-redshift UDGs are more flattened, compared with the low-redshift counterparts, which plausibly suggests a "disky" origin for the high-redshift, newly born UDGs.

Keywords: Dwarf galaxies, Galaxy evolution, Galaxy photometry
A Detailed Study of Massive Galaxies in a Protocluster at z = 3.13. We present a detailed study of near-IR selected galaxies in a protocluster field at z = 3.13. Protocluster galaxies are selected using the available mutliwavelength data with the photometric redshifts (photo-z) at 2.9 &lt; z &lt; 3.3, reaching a mass completeness of $\simeq {10}^{10}\,{M}_{\odot }$ . Diverse types of galaxies have been found in the field, including normal star-forming galaxies, quiescent galaxies, and dusty star-forming galaxies. The photo-z galaxies form two large overdense structures in the field, largely overlapping with the previously identified galaxy overdensities traced by Lyα emitters (LAEs) and Lyman break galaxies, respectively. The northern overdensity consists of a large fraction of old and/or dusty galaxy populations, while the southern one is mainly composed of normal star-forming galaxies that are spatially correlated with the LAEs. This agrees with our previous study arguing the spatial offset of different galaxy overdensities may be due to halo assembly bias. Given the large end-to-end sizes of the two overdensities, one possibility is that they will form into a supercluster by the present day. We also find strong evidence that the star formation activities of the galaxies in the overdense protocluster regions are enhanced in comparison to their field counterparts, which suggests an accelerated mass assembly in this protocluster.

Keywords: Protoclusters
Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy and a Thin Disk Model with Finite Thickness. X-ray reflection spectroscopy is a powerful tool for probing the strong gravity region of black holes and can be used for testing general relativity in the strong field regime. Simplifications of the available relativistic reflection models limit the capability of performing accurate measurements of the properties of black holes. In this paper, we present an extension of the model RELXILL_NK in which the accretion disk has a finite thickness rather than being infinitesimally thin. We employ the accretion disk geometry proposed by Taylor &amp; Reynolds and we construct relativistic reflection models for different values of the mass accretion rate of the black hole. We apply the new model to high-quality Suzaku data of the X-ray binary GRS 1915+105 to explore the impact of the thickness of the disk on tests of the Kerr metric.

Keywords: X-ray astronomy, Kerr metric, Astrophysical black holes
Relating the Structure of Dark Matter Halos to Their Assembly and Environment. We use a large N-body simulation to study the relation of the structural properties of dark matter halos to their assembly history and environment. The complexity of individual halo assembly histories can be well described by a small number of principal components (PCs), which, compared to formation times, provide a more complete description of halo assembly histories and have a stronger correlation with halo structural properties. Using decision trees built with the random ensemble method, we find that about 60%, 10%, and 20% of the variances in halo concentration, axis ratio, and spin, respectively, can be explained by combining four dominating predictors: the first PC of the assembly history, halo mass, and two environment parameters. Halo concentration is dominated by halo assembly. The local environment is found to be important for the axis ratio and spin but is degenerate with halo assembly. The small percentages of the variance in the axis ratio and spin that are explained by known assembly and environmental factors suggest that the variance is produced by many nuanced factors and should be modeled as such. The relations between halo intrinsic properties and environment are weak compared to their variances, with the anisotropy of the local tidal field having the strongest correlation with halo properties. Our method of dimension reduction and regression can help simplify the characterization of the halo population and clarify the degeneracy among halo properties.

Keywords: Galaxy dark matter halos
The Discovery of a Hidden Broad-line AGN in a Bulgeless Galaxy: Keck NIR Spectroscopic Observations of SDSS J085153.64+392611.76. We report the discovery of a buried, active supermassive black hole (SMBH) in SDSS J085153.64+392611.76, a bulgeless Seyfert 2 (Sy2) galaxy. Keck near-infrared observations reveal a hidden broad-line region, allowing for the rare case where strong constraints can be placed on both the BH mass and bulge component. Using virial mass estimators, we obtain a BH mass of log(MBH/M⊙) = 6.78 ± 0.50. This is one of the only Sy2 active galactic nuclei (AGNs) hosted in a bulgeless galaxy with a virial BH mass estimate and could provide important constraints on the formation scenarios of the BH seed population. The lack of a bulge component suggests that the SMBH has grown quiescently, likely caused by secular processes independent of major mergers. In the absence of a detectable bulge component, we find the MBH-Mstellar relation to be more reliable than the MBH-Mbulge relation. In addition, we detect extended narrow Paα emission that allows us to create a rotation curve where we see counterrotating gas within the central kiloparsec. Possible causes of this counterrotation include a galactic bar or disruption of the inner gas by a recent fly-by of a companion galaxy. This in turn could have triggered accretion onto the central SMBH in the current AGN phase.

Keywords: Supermassive black holes, Galaxy bulges, Seyfert galaxies, Active galactic nuclei, Near infrared astronomy
A Catalog of 531 White Dwarf Candidates in the Local Galactic Halo from Gaia Data Release 2. We present a catalog of 531 white dwarf candidates that have large apparent transverse motions relative to the Sun ( ${v}_{T}\gt 200$ km s-1), thus making them likely members of the local Galactic halo population. The candidates were selected from the Gaia Data Release 2 and are located in a great circle with 20° width running across both Galactic poles and the Galactic center and anticenter, a zone that spans 17.3% of the sky. The selection used a combination of kinematic and photometric properties, derived primarily from Gaia proper motions, G magnitudes, and ${G}_{\mathrm{BP}}-{G}_{\mathrm{RP}}$ color, and including parallax whenever available. Additional validation of the white dwarf candidates is made using PanSTARRS photometric (gri) data. Our final catalog includes not only stars having full kinematic and luminosity estimates from reliable Gaia parallax, but also stars with presently unreliable or no available Gaia parallax measurements. We argue that our method of selecting local halo objects with and without reliable parallax data leads us to round up all possible halo white dwarfs in the Gaia catalog (in that particular section of the sky) with recorded proper motions $\gt 40$ mas yr-1 and that pass our ${v}_{T}\gt 200$ km s-1 threshold requirement. We expect this catalog will be useful for the study of the white dwarf population of the local Galactic halo.

Keywords: Stellar kinematics, White dwarf stars, High-velocity stars, Proper motions, Halo stars, Catalogs
Bar Classification Based on the Potential Map. We introduce a new approach to classify barred galaxies that utilizes the transverse-to-radial force ratio map (ratio map, hereafter) in a different manner from previous studies. When we display the ratio map in polar coordinates, barred galaxies appear as four aligned, horizontal thick slabs. This characteristic feature enables us to successfully classify barred and nonbarred galaxies with an accuracy of 87%. It yields a bar fraction of 53%, including both SBs and SABs, when applied to 884 nearby (z &lt; 0.01) spiral galaxies from the Sloan Digital Sky Survey/DR7. It also provides the bar strength and length measurements, in particular, separated from the spiral arms. They show good correlations with the measures estimated from ellipse fitting and Fourier analysis. However, we find different tendencies of the bar strength measurements in terms of the Hubble sequence: as the Hubble sequence increases (toward late types), the bar strength and bar ellipticity increase, whereas the dipole Fourier amplitude decreases. We show that the bulge affects the estimation of the bar strength differently, depending on the classification methods. The bulge causes the bar length to be overestimated in all three methods. Meanwhile, we find that barred galaxies show two types of radial profiles of the angle-averaged force ratio: one has a maximum peak (type M) and the other a plateau (type P). Comparison with numerical simulations suggests that type-M bars are more mature than type-P bars in terms of evolutionary stage.

Keywords: Galaxy evolution, Galaxy structure, Galaxy classification systems, Galaxy properties
The Morphology-Density Relationship in 1 &lt; z &lt; 2 Clusters. The morphology-density relationship states that dense cosmic environments such as galaxy clusters have an overabundance of quiescent elliptical galaxies, but it is unclear at which redshift this relationship is first established. We study the morphology of four clusters with 1.2 &lt; z &lt; 1.8 using Hubble Space Telescope imaging and the morphology computation code STATMORPH. By comparing the median morphology of cluster galaxies to CANDELS field galaxies using Monte Carlo analysis, we find that two out of four clusters (at z = 1.19 and 1.75) have an established morphology-density relationship with more than 3σ significance. Approximately 50% of the galaxies in these clusters are bulge-dominated, compared to ∼30% in the field, and they are significantly more compact. This result is more significant for low-mass galaxies with $\mathrm{log}M/{M}_{\odot }\lessapprox 10.5$ , showing that low-mass galaxies are affected the most in clusters. We also find an intriguing system of two z ≈ 1.45 clusters at a unusually small 2D separation of 3' and 3D separation of ≈73 Mpc that exhibit no morphology-density relationship but have enhanced merger signatures. We conclude that the environmental mechanism responsible for the morphology-density relationship is (1) already active as early as z = 1.75; (2) forms compact, bulge-dominated galaxies; and (3) affects primarily low-mass galaxies. However, there is a significant degree of intracluster variance that may depend on the larger cosmological environment in which the cluster is embedded.

Keywords: Galaxies, Galaxy evolution, Galaxy classification systems, High-redshift galaxy clusters