adsabs/SciX_UAT_keywords huggingface dataset:
Investigating the M GCS-M h Relation in the Most Massive Galaxies

The relation between the total mass contained in the globular clusters of a galaxy and the mass of its dark-matter halo has been found observationally to be nearly linear over five decades of mass. However, the high-mass end of this relation is not well determined from previous data and shows large scatter. We analyze the globular cluster systems (GCSs) of a homogeneous sample of 11 brightest cluster galaxies (BCGs) through DOLPHOT photometry of their deep Hubble Space Telescope images in the F814W filter. We standardize the definition of M GCS, the total GCS mass, by using the GC total population within a limiting radius of 0.1R virial, while the dark-matter halo mass M h is determined from the weak-lensing calibration of M h versus M bary. When these 11 BCGs are added to the previously studied homogeneous catalog of Virgo member galaxies, a total value for η = M GCS/M h is found to be (3.0 ± 1.8internal) × 10-5, slightly higher than previous estimates but with much reduced uncertainty. Perhaps more importantly, the results suggest that the relation continues to have a near-linear shape at the highest galaxy masses, strongly reinforcing the conclusion that accreted GCs make a major contribution to the GC populations at high galaxy mass.

Keywords: globular star clusters; brightest cluster galaxies; galaxy dark matter halos; elliptical galaxies
Mid-infrared Outbursts in Nearby Galaxies (MIRONG). I. Sample Selection and Characterization

Optical time-domain astronomy has grown rapidly in the past decade, but the dynamic infrared sky is rarely explored. Aiming to construct a sample of mid-infrared outbursts in nearby galaxies (MIRONG), we have conducted a systematical search of low-redshift (z < 0.35) Sloan Digital Sky Survey spectroscopic galaxies that have experienced recent mid-infrared (MIR) flares using their Wide-field Infrared Survey Explorer (WISE) light curves. A total of 137 galaxies have been selected by requiring a brightening amplitude of 0.5 mag in at least one WISE band with respect to their quiescent phases. Only a small fraction (10.9%) has corresponding optical flares. Except for the four supernovae (SNe) in our sample, the MIR luminosities of the remaining sources (L4.6 μm > 1042 erg s-1) are markedly brighter than known SNe, and their physical locations are very close to the galactic center (median <0"1). Only four galaxies are radio-loud, indicating that synchrotron radiation from relativistic jets could contribute to MIR variability. We propose that these MIR outbursts are dominated by the dust echoes of transient accretion onto supermassive black holes, such as tidal disruption events (TDEs) and turn-on (changing-look) active galactic nuclei. Moreover, the inferred peak MIR luminosity function is generally consistent with the X-ray and optical TDEs at the high end, albeit with large uncertainties. Our results suggest that a large population of transients has been overlooked by optical surveys, probably due to dust obscuration or intrinsically optical weakness. Thus, a search in the infrared band is crucial for us to obtain a panoramic picture of nuclear outburst. The multiwavelength follow-up observations of the MIRONG sample are in progress and will be presented in a series of subsequent papers.

Keywords: time domain astronomy; tidal disruption; active galactic nuclei; infrared astronomy
The Decoupling of Binaries from Their Circumbinary Disks

We have investigated, both analytically and numerically, accreting supermassive black hole binaries as they inspiral due to gravitational radiation to elucidate the decoupling of binaries from their disks and inform future multimessenger observations of these systems. Our numerical studies evolve equal-mass binaries from initial separations of 100 GM c-2 until merger, resolving scales as small as ~0.04 GM c-2, where M is the total binary mass. Our simulations accurately capture the point at which the orbital evolution of each binary decouples from that of its circumbinary disk, and precisely resolve the flow of gas throughout the inspiral. We demonstrate analytically and numerically that timescale-based predictions overestimate the binary separations at which decoupling occurs by factors of ~3, and illustrate the utility of a velocity-based decoupling criterion. High-viscosity (ν ≳ 0.03 GM c-2) circumbinary systems decouple late (a b ≲ 15 GM c-2) and have qualitatively similar morphologies near merger to circumbinary systems with constant binary separations. Lower-viscosity circumbinary disks decouple earlier and exhibit qualitatively different accretion flows, which lead to precipitously decreasing accretion onto the binary. If detected, such a decrease may unambiguously identify the host galaxy of an ongoing event within a LISA error volume. We illustrate how accretion amplitude and variability evolve as binaries gradually decouple from their circumbinary disks, and where decoupling occurs over the course of binary inspirals in the LISA band. We show that, even when dynamically negligible, gas may leave a detectable imprint on the phase of gravitational waves.

Keywords: active galactic nuclei; accretion; gravitational wave astronomy; hydrodynamical simulations
Detection of a High-velocity Jet from MWC 349A Traced by Hydrogen Recombination Line Maser Emission

MWC 349A is one of the rare stars known to have hydrogen radio recombination line (RRL) masers. The bright maser emission makes it possible to study the dynamics of the system at milliarcsecond (mas) precision. We present Atacama Large Millimeter/submillimeter Array observations of the 1.4 and 0.8 mm continuum emission of MWC 349A, as well as the H30α and H26α RRLs. Using the most extended array configuration of C43-10 with a maximum baseline of 16.2 km, we spatially resolved the H30α line and 1.4 mm continuum emission for the first time. In addition to the known H30α and H26α maser emission from a Keplerian disk at LSR velocities from -12 to 28 km s-1 and from an ionized wind for velocities between -12 to -40 km s-1 and 28 to 60 km s-1, we found evidence of a jet along the polar axis at V LSR from -85 to -40 km s-1 and +60 to +100 km s-1. These masers are found in a linear structure nearly aligned with the polar axis of the disk. If these masers lie close to the polar axis, their velocities could be as high as 575 km s-1, which cannot be explained solely by a single expanding wind as proposed in Báez-Rubio et al. We suggest that they originate from a high-velocity jet, likely launched by a magnetohydrodynamic wind. The jet appears to rotate in the same direction as the rotation of the disk. A detailed radiative transfer modeling of these emissions will further elucidate the origin of these masers in the wind.

Keywords: star formation; circumstellar disks; astrophysical masers; jets; interferometry; evolved stars
Searching for Extragalactic Exoplanetary Systems: The Curious Case of BD+20 2457

Planets and their host stars carry a long-term memory of their origin in their chemical compositions. Thus, identifying planets formed in different environments improves our understating of planetary formation. Although restricted to detecting exoplanets within the solar vicinity, we might be able to detect planetary systems that formed in small external galaxies and later merged with the Milky Way. In fact, Gaia data have unequivocally shown that the Galaxy underwent several significant minor mergers during its first billion years of formation. The stellar debris of one of these mergers, Gaia-Enceladus (GE), is thought to have built up most of the stellar halo in the solar neighborhood. In this Letter, we investigate the origin of known planet-host stars combining data from the NASA Exoplanet Archive with Gaia EDR3 and large-scale spectroscopic surveys. We adopt a kinematic criterion and identify 42 stars associated with the Milky Way's thick disk and one halo star. The only halo star identified, BD+20 2457, known to harbor two exoplanets, moves on a retrograde and highly eccentric orbit. Its chemical abundance pattern situates the star at the border between the thick disk, the old halo, and accreted populations. Given its orbital parameters and chemical properties, we suggest that BD+20 2457 is likely formed in the protodisk of the Galaxy, but we do not exclude the possibility of the star belonging to the debris of GE. Finally, we estimate a minimum age and mass limit for the star, which has implications for its planetary system and will be tested with future Transiting Exoplanet Survey Satellite observations.

Keywords: galaxy dynamics; exoplanets; milky way stellar halo; galaxy kinematics
Comparative Study of TESS Photometry and Radial Velocities on Six Early K-type Contact Binaries with Similar Periods around 0.268 Day

High-precision light curves were extracted from TESScut images. Together with APOGEE and LAMOST medium-resolution spectra, a joint study was made for six early K-type contact binary candidates selected unbiasedly with orbital periods around 0.268 day. It is found that all of them (RV CVn, EK Com, V384 Ser, V1038 Her, EH CVn, and CSS_J125403.7+503945) are W-subtype shallow contact systems, though with different mass ratios (1/q = 0.27-0.62). The effective temperature differences between the binary components are around a few hundred kelvins. The original definitions of the A and W subtypes were compared with the customarily used methods, which rely on the shape or photometric solutions of the light curves. The latter two methods are not always reliable; therefore, the radial velocity analysis is strongly recommended. Through a collection of all available K-type contact binaries with both photometric and spectroscopic measurements, it is found that almost all of them are W-subtype systems, except for a few objects that have nearly identical temperatures for binary components. This W-subtype phenomenon for K-type contact binaries should be further checked with more samples in the future. Finally, the physical parameters of the targets were determined with joint data analysis, and the multiplicity is discussed for these targets. Objects V384 Ser and RV CVn are confirmed to very likely be triple systems from comprehensive analysis, while V1038 Her is a candidate of a triple system based on photometric and spectroscopic solutions.

Keywords: eclipsing binary stars; fundamental parameters of stars; late-type stars; contact binary stars; radial velocity
Modeling the JWST High-redshift Galaxies with a General Formation Scenario and the Consistency with the ΛCDM Model

Early results from the James Webb Space Telescope (JWST) observations have hinted at two traces beyond the standard cosmological framework. One is the extraordinarily high stellar masses and their density at z = 7.5 ~ 9.1; another is the unexpected abundance of ultraviolet (UV) bright galaxies at z ≥ 10. Nevertheless, both pieces of evidence are not statistically robust yet. In this work, we construct rest-frame UV luminosity functions (LFs) based on a general formation model for these high-redshift galaxy candidates, since UV LFs always carry the information of stellar formation efficiency (SFE), initial mass function (IMF), dust attenuation, and other crucial elements for galaxy evolution. By updating the massive galaxies candidates with spectroscopic observations and exploring the parameter space of SFE, we are able to reasonably explain the cumulative stellar mass density within the redshift range of 7.5-9.1, with only one galaxy exhibiting unusual characteristics. We also reveal a potential nonmonotonic trend of SFE with the increasing redshift. At higher redshift (z ~ 13), bright UV LFs can be well fitted with non-dust attenuation or top-heavy IMF for Population III stars. The Population III star scenario can also naturally account for the possible dip of the peak SFE evolution curve at z ~ 9.

Keywords: early universe; high-redshift galaxies; galaxy formation; james webb space telescope
The Detection of Deuterated Water in the Large Magellanic Cloud with ALMA

We report the first detection of deuterated water (HDO) toward an extragalactic hot core. The HDO 211-212 line has been detected toward hot cores N 105-2 A and 2 B in the N 105 star-forming region in the low-metallicity Large Magellanic Cloud (LMC) dwarf galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA). We have compared the HDO line luminosity (L HDO) measured toward the LMC hot cores to those observed toward a sample of 17 Galactic hot cores covering three orders of magnitude in L HDO, four orders of magnitude in bolometric luminosity (L bol), and a wide range of Galactocentric distances (thus metallicities). The observed values of L HDO for the LMC hot cores fit very well into the L HDO trends with L bol and metallicity observed toward the Galactic hot cores. We have found that L HDO seems to be largely dependent on the source luminosity, but metallicity also plays a role. We provide a rough estimate of the H2O column density and abundance ranges toward the LMC hot cores by assuming that HDO/H2O toward the LMC hot cores is the same as that observed in the Milky Way; the estimated ranges are systematically lower than Galactic values. The spatial distribution and velocity structure of the HDO emission in N 105-2 A is consistent with HDO being the product of the low-temperature dust grain chemistry. Our results are in agreement with the astrochemical model predictions that HDO is abundant regardless of the extragalactic environment and should be detectable with ALMA in external galaxies.

Keywords: star formation; astrochemistry; magellanic clouds; chemical abundances; star forming regions; protostars
ASpatially Resolved Observations of Europa's Surface with Subaru/IRCS at 1.0-1.8 μm: Upper Limits to the Abundances of Hydrated Cl-bearing Salts

Recent infrared observations at 1.5-4.0 μm using large ground-based telescopes have suggested that Cl-bearing salts are likely present on Europa's surface as non-ice materials. The chemical compositions of those Cl-bearing salts are key to understanding Europa's ocean chemistry and habitability. Here we report the results of ground-based telescope observations of Europa across two wavelength ranges, 1.0-1.5 μm and 1.5-1.8 μm, of which the former range includes absorption features due to some hydrated Cl-bearing salts. We obtained spatially resolved reflectance spectra using the Subaru telescope/IRCS and the adaptive optics system AO188 with high wavelength resolutions (δλ ~ 2 nm for 1.0-1.5 μm and δλ ~ 0.9 nm for 1.5-1.8 μm) and low noise levels (1σ ~ (1-2) × 10-3). We found no clear absorption features at ~1.2 μm caused by hydrated Cl-bearing salts. We estimated that conservative upper limits to the abundances of MgCl2 · nH2O, NaClO4 · 2H2O, Mg(ClO3)2 · 6H2O, and Mg(ClO4)2 · 6H2O on Europa are 17% (<10% for most) at the 3σ noise level. These values are lower than the proposed abundance of some hydrated Cl-bearing salts (>~20%) on Europa based on previous observations. This supports the idea that Cl-bearing salts on Europa are likely anhydrous Na salts of NaCl and/or NaClO4, or hydrated NaCl · 2H2O. The presence of Na salts suggests that Na+ could be the major cation in Europa's ocean, which would be possible if the oceanic pH is circumneutral or alkaline.

Keywords: europa; surface composition; planetary surfaces; jovian satellites; near infrared astronomy; chemical abundances
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: quasars; supermassive black holes; galaxy clusters; active galactic nuclei; galaxy evolution; galaxy jets
UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec-Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1

The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from "seeds" to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z > 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z = 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z ≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates ( ${M}_{\star }\sim {1.4}_{-0.4}^{+0.3}\times {10}^{8}$ M ⊙). Given the predicted BH mass (M BH ~ 107-108 M ⊙), the resulting ratio of M BH/M ⋆ remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution.

Keywords: active galactic nuclei; early universe; high-redshift galaxies
Deciphering Radio Emissions from Accretion Disk Winds in Radio-quiet Active Galactic Nuclei

Unraveling the origins of radio emissions from radio-quiet active galactic nuclei (RQ AGNs) remains a pivotal challenge in astrophysics. One potential source of this radiation is the shock interaction between AGN disk winds and the interstellar medium (ISM). To understand this phenomenon, we construct a spherical, one-zone, and self-similar expansion model of shock structure between ultrafast outflows (UFOs) and the ISM. We then calculate the energy density distribution of nonthermal electrons by solving the transport equation, considering diffusive shock acceleration as the acceleration mechanism and synchrotron and inverse Compton cooling as the cooling mechanisms. Based on the derived energy distribution of nonthermal electrons, we model the radio synchrotron spectrum of the shocked ISM. For the 15 nearby RQ AGNs hosting UFOs, we investigate the shocked ISM parameters required to model their observed radio spectra based on X-ray observations and measured UFO velocities. Radio spectra of 11 out of 15 nearby RQ AGNs would be explained by the AGN disk wind model. This is a compelling indication that shock interactions between AGN disk winds and the ISM could indeed be the source of their radio emissions. The typical predicted source size and magnetic field strength are several 100 pc and 0.1 mG, respectively. We also discuss whether our prediction can be tested by future radio observations.

Keywords: active galactic nuclei; extragalactic radio sources; non-thermal radiation sources; high energy astrophysics; seyfert galaxies
Redshift Evolution of Electron Density in the Interstellar Medium at z 0-9 Uncovered with JWST/NIRSpec Spectra and Line-spread Function Determinations

We present electron densities n e in the interstellar medium (ISM) of star-forming galaxies at z = 4-9 observed by the JWST/NIRSpec GLASS, Early Release Observations, and CEERS programs. We carefully evaluate the line-spread functions of the NIRSpec instrument as a function of wavelength with the calibration data of a planetary nebula taken on board, and obtain secure [O II] λ λ3726, 3729 doublet fluxes for 14 galaxies at z = 4.02-8.68 falling on the star formation main sequence with the NIRSpec high- and medium-resolution spectra. We thus derive the electron densities of singly ionized oxygen nebulae with the standard n e indicator of the [O II] doublet, and find that the electron densities of the z = 4-9 galaxies are n e ≳ 300 cm-3 significantly higher than those of low-z galaxies at a given stellar mass, star formation rate (SFR), and specific SFR. Interestingly, the typical electron densities of the singly ionized nebulae increase from z = 0 to z = 1-3 and z = 4-9, which is approximated by the evolutionary relation of n e ∝ (1 + z) p with p ~ 1-2. Although it is not obvious that the ISM property of n e is influenced by global galaxy properties, these results may suggest that the nebula densities of high-z galaxies are generally high due to the compact morphologies of high-z galaxies evolving by ${r}_{{\rm{e}}}\mathop{\propto }\limits_{\sim }{(1+z)}^{-1}$ (r vir ∝ (1 + z)-1) for a given stellar (halo) mass whose inverse square corresponds to the p ~ 2 evolutionary relation. The p ~ 1-2 evolutionary relation can be explained by a combination of the compact morphology and the reduction of n e due to the high electron temperature of high-z metal-poor nebulae.

Keywords: galaxy formation; galaxy structure; star formation; dwarf galaxies
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; catalogs; x-ray quasars; radio loud quasars; spectral energy distribution