Sazuna/UAT_keywords huggingface dataset:
The Ca II Lines as Tracers of Disk Structure in T Tauri Stars: The Chamaeleon I Region. We present a study of the Ca II K and IR triplet lines in a sample of classical T Tauri stars in the Chamaeleon I star-forming region. We study X-shooter spectra of the stars in the sample and find that in some of these stars the Ca II lines are much weaker than expected from their H line fluxes and mass accretion rates. Since the Ca II K lines have characteristic magnetospheric accretion line profiles and the magnetospheric flows feed directly from the inner disk, we interpret the Ca deficiency in terms of depletion due to processes happening in the disk. To test this hypothesis, we define a coarse depletion indicator using the flux of the Ca II K line and show that it correlates with disk properties. In particular, using indicators extracted from Spitzer/IRS spectra, we obtain that all the transitional and pretransitional disks of the sample show depletion, consistent with the trapping of refractories in pressure bumps created by planets and/or in the planets themselves. We find full disks with Ca depletion in the sample that also show indications of advanced dust evolution. We apply magnetospheric accretion models to fit the Balmer and Ca II line fluxes of a star showing clear Ca depletion and derive a Ca abundance in its inner disk of about 17% solar.

Keywords: Stellar accretion, Protoplanetary disks, Chemical abundances
Hierarchical Inference of the Lensing Convergence from Photometric Catalogs with Bayesian Graph Neural Networks. We present a Bayesian graph neural network (BGNN) that can estimate the weak lensing convergence (κ) from photometric measurements of galaxies along a given line of sight (LOS). The method is of particular interest in strong gravitational time-delay cosmography (TDC), where characterizing the "external convergence" (κ ext) from the lens environment and LOS is necessary for precise Hubble constant (H 0) inference. Starting from a large-scale simulation with a κ resolution of ~1', we introduce fluctuations on galaxy-galaxy lensing scales of ~1″ and extract random sight lines to train our BGNN. We then evaluate the model on test sets with varying degrees of overlap with the training distribution. For each test set of 1000 sight lines, the BGNN infers the individual κ posteriors, which we combine in a hierarchical Bayesian model to yield constraints on the hyperparameters governing the population. For a test field well sampled by the training set, the BGNN recovers the population mean of κ precisely and without bias (within the 2σ credible interval), resulting in a contribution to the H 0 error budget well under 1%. In the tails of the training set with sparse samples, the BGNN, which can ingest all available information about each sight line, extracts a stronger κ signal compared to a simplified version of the traditional method based on matching galaxy number counts, which is limited by sample variance. Our hierarchical inference pipeline using BGNNs promises to improve the κ ext characterization for precision TDC. The code is available as a public Python package, NODE TO JOY ⏬.

Keywords: Cosmology, Weak gravitational lensing, Bayesian statistics, Neural networks, Strong gravitational lensing, Hubble constant, Hierarchical models, Astronomical simulations
A Search for Relativistic Ejecta in a Sample of ZTF Broad-lined Type Ic Supernovae. The dividing line between gamma-ray bursts (GRBs) and ordinary stripped-envelope core-collapse supernovae (SNe) is yet to be fully understood. Observationally mapping the variety of ejecta outcomes (ultrarelativistic, mildly relativistic, or nonrelativistic) in SNe of Type Ic with broad lines (Ic-BL) can provide a key test to stellar explosion models. However, this requires large samples of the rare SN Ic-BL events with follow-up observations in the radio, where fast ejecta can be probed largely free of geometry and viewing angle effects. Here, we present the results of a radio (and X-ray) follow-up campaign of 16 SNe Ic-BL detected by the Zwicky Transient Facility (ZTF). Our radio campaign resulted in four counterpart detections and 12 deep upper limits. None of the events in our sample is as relativistic as SN 1998bw and we constrain the fraction of SN 1998bw-like explosions to &lt;19% (3σ Gaussian equivalent), a factor of ≈2 smaller than previously established. We exclude relativistic ejecta with radio luminosity densities in between ≈5 × 1027 erg s-1 Hz-1 and ≈1029 erg s-1 Hz-1 at t ≳ 20 days since explosion for ≈60% of the events in our sample. This shows that SNe Ic-BL similar to the GRB-associated SNe 1998bw, 2003lw, and 2010bh, or to the relativistic SNe 2009bb and iPTF17cw, are rare. Our results also exclude an association of the SNe Ic-BL in our sample with largely off-axis GRBs with energies E ≳ 1050 erg. The parameter space of SN 2006aj-like events (faint and fast-peaking radio emission) is, on the other hand, left largely unconstrained, and systematically exploring it represents a promising line of future research.

Keywords: Extragalactic radio sources, Gamma-ray bursts, Core-collapse supernovae
Detection of the Low-stellar-mass Host Galaxy of a z 6.25 Quasar with JWST. We characterize the stellar mass of J2239+0207, a z ~ 6.25 sub-Eddington quasar (M 1450 = -24.6), using dedicated JWST/NIRCam medium-band observations of a nearby point-spread function star to remove the central point source and reveal the underlying galaxy emission. We detect the host galaxy in two bands longward of the Balmer break, obtaining a stellar mass of ~1010 M ⊙, more than an order of magnitude less than this quasar's existing measured [C II] dynamical mass. We additionally calculate the mass of J2239+0207's central supermassive black hole using JWST/NIRSpec integral field unit observations, and determine that the black hole is ~15 times more massive than predicted by the local M BH-M * relation, similar to many high-redshift quasars with dynamical masses determined via millimeter-wave line widths. We carefully consider potential selection effects at play, and find that even when z ~ 6 quasars are compared to a local sample with similarly determined dynamical masses, many of the high-redshift quasars appear to possess overmassive black holes. We conclude z ~ 6 quasars are likely to have a larger spread about the M BH-M * relation than observed in the local Universe.

Keywords: Quasar-galaxy pairs, Quasars
S-type Stars: Line List for the A<SUP>2</SUP>Π-X<SUP>2</SUP>Σ<SUP>+</SUP> Band System of LaO. LaO bands are found in the spectra of cool S-type stars. The bands of the A2Π-X2Σ+ transition with $v^{\prime} \leqslant 3$ and v″ ≤ 4 are rotationally analyzed, providing spectroscopic constants for the A2Π state. Line strengths are calculated using an ab initio transition dipole moment function, and radiative lifetimes for the A2Π state have also been computed. A line list for the A2Π-X2Σ+ transition of LaO is provided and can be used to determine LaO stellar abundances.

Keywords: Spectral line lists, Line positions, Line intensities, Spectroscopy
Asteroseismic Modeling of 1153 Kepler Red Giant Branch Stars: Improved Stellar Parameters with Gravity-mode Period Spacings and Luminosity Constraints. This paper reports the estimated stellar parameters of 1153 Kepler red giant branch stars determined with asteroseismic modeling. We use radial-mode oscillation frequencies, gravity-mode period spacings, Gaia luminosities, and spectroscopic data to characterize these stars. Compared with previous studies, we find that the two additional observed constraints, i.e., the gravity-mode period spacing and luminosity, significantly improve the precision of fundamental stellar parameters. The typical uncertainties are 2.9% for the mass, 11% for the age, 1.0% for the radius, 0.0039 dex for the surface gravity, and 0.5% for the helium core mass, making this the best-characterized large sample of red giant stars available to date. With better characterizations for these red giants, we recalibrate the seismic scaling relations and study the surface term on the red giant branch. We confirm that the surface term depends on the surface gravity and effective temperature, but there is no significant correlation with metallicity.

Keywords: Asteroseismology
Large Myr-old Disks Are Not Severely Depleted of Gas-phase CO or Carbon. We present an ACA search for [C I] 1-0 emission at 492 GHz toward large T Tauri disks (gas radii ≳ 200 au) in the ~1-3 Myr-old Lupus star-forming region. Combined with Atacama Large Millimeter/submillimeter Array 12 m archival data for IM Lup, we report [C I] 1-0 detections in six out of 10 sources, thus doubling the known detections toward T Tauri disks. We also identify four Keplerian double-peaked profiles and demonstrate that the [C I] 1-0 fluxes correlate with 13CO, C18O, and 12CO(2-1) fluxes, as well as with the gas disk outer radius measured from the latter transition. These findings are in line with the expectation that atomic carbon traces the disk surface. In addition, we compare the carbon and carbon monoxide (CO) line luminosities of a Lupus and literature sample with [C I] 1-0 detections with predictions from the self-consistent disk thermo-chemical models of Ruaud et al. These models adopt interstellar medium carbon and oxygen elemental abundances as input parameters. With the exception of the disk around Sz 98, we find that these models reproduce all the available line luminosities and upper limits, with gas masses comparable to or higher than the minimum-mass solar nebula and gas-to-dust mass ratios ≥10. Thus, we conclude that the majority of large Myr-old disks conform to the simple expectation that they are not significantly depleted in gas, CO, or carbon.

Keywords: Millimeter astronomy, Exoplanet formation, Protoplanetary disks, CO line emission
Confronting a Thin Disk-wind Launching Mechanism of Broad-line Emission in Active Galactic Nuclei with GRAVITY Observations of Quasar 3C 273. Quasars show a remarkable degree of atomic emission-line broadening, an observational feature which, in conjunction with a radial distance estimate for this emission from the nucleus, is often used to infer the mass of the central supermassive black hole. The radius estimate depends on the structure and kinematics of this so-called broad-line region, which is often modeled as a set of discrete emitting clouds. Here, we test an alternative kinematic disk-wind model of optically thick line emission originating from a geometrically thin accretion disk under Keplerian rotation around a supermassive black hole. We use this model to calculate broad emission-line profiles and interferometric phases to compare to GRAVITY data and previously published cloud modeling results. While we show that such a model can provide a statistically satisfactory fit to GRAVITY data for quasar 3C 273, we disfavor it as it requires 3C 273 be observed at high inclination, which observations of the radio jet orientation do not support.

Keywords: Astronomy data modeling, Theoretical models, Quasars, Reverberation mapping, Active galactic nuclei, Interferometry
Dark Matter Halo Properties of the Galactic Dwarf Satellites: Implication for Chemo-dynamical Evolution of the Satellites and a Challenge to Lambda Cold Dark Matter. Elucidating dark matter density profiles in Galactic dwarf satellites is essential to understanding not only the quintessence of dark matter, but also the evolution of the satellites themselves. In this work, we present the current constraints on dark matter densities in Galactic ultrafaint dwarf (UFD) and diffuse galaxies. Applying our constructed nonspherical mass models to the currently available kinematic data of the 25 UFDs and two diffuse satellites, we find that whereas most of the galaxies have huge uncertainties on the inferred dark matter density profiles, Eridanus II, Segue I, and Willman 1 favor cuspy central profiles even when considering effects of a prior bias. We compare our results with the simulated subhalos on the plane between the dark matter density at 150 pc and the pericenter distance. We find that the most observed satellites and the simulated subhalos are similarly distributed on this plane, except for Antlia 2, Crater 2, and Tucana 3, which are less than one-tenth of the density. Despite considerable tidal effects, the subhalos detected by commonly used subhalo finders have difficulty explaining such a huge deviation. We also estimate the dynamical mass-to-light ratios of the satellites and confirm the ratio is linked to stellar mass and metallicity. Tucana 3 deviates largely from these relations, while it follows the mass-metallicity relation. This indicates that Tucana 3 has a cored dark matter halo, despite a significant uncertainty in its ratios.

Keywords: Local Group, Galaxy structure, Galaxy dynamics, Dark matter density, Galaxy kinematics, Dwarf spheroidal galaxies, Dark matter
Investigating the Origin of the Absorption-line Variability in the Narrow-line Seyfert 1 Galaxy WPVS 007. Broad absorption line quasars are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depending on the source. WPVS 007, a low-redshift, low-luminosity narrow-line Seyfert 1 (NLS1) shows strong variability over shorter timescales, providing a unique opportunity to study the driving mechanism behind this variability that may mimic longer-scale variability in much more massive quasars. We present the first variability study using the spectral synthesis code SimBAL, which provides velocity-resolved changes in physical conditions of the gas using constraints from multiple absorption lines. Overall, we find WPVS 007 to have a highly ionized outflow with a large mass-loss rate and kinetic luminosity. We determine the primary cause of the absorption-line variability in WPVS 007 to be a change in covering fraction of the continuum by the outflow. This study is the first SimBAL analysis where multiple epochs of observation were fit simultaneously, demonstrating the ability of SimBAL to use the time domain as an additional constraint in spectral models.

Keywords: Active galactic nuclei, Quasars, Spectroscopy, Broad-absorption line quasar
Statistical Relationship between Long-duration High-energy Gamma-Ray Emission and Solar Energetic Particles. Large solar eruptions are often associated with long-duration γ-ray emission extending well above 100 MeV. While this phenomenon is known to be caused by high-energy ions interacting with the solar atmosphere, the underlying dominant acceleration process remains under debate. Potential mechanisms include continuous acceleration of particles trapped within large coronal loops or acceleration at coronal mass ejection (CME)-driven shocks, with subsequent back-propagation toward the Sun. As a test of the latter scenario, previous studies have explored the relationship between the inferred particle population producing the high-energy γ-rays and the population of solar energetic particles (SEPs) measured in situ. However, given the significant limitations on available observations, these estimates unavoidably rely on a number of assumptions. In an effort to better constrain theories of the γ-ray emission origin, we reexamine the calculation uncertainties and how they influence the comparison of these two proton populations. We show that, even accounting for conservative assumptions related to the γ-ray flare, SEP event, and interplanetary scattering modeling, their statistical relationship is only poorly/moderately significant. However, though the level of correlation is of interest, it does not provide conclusive evidence for or against a causal connection. The main result of this investigation is that the fraction of the shock-accelerated protons required to account for the γ-ray observations is &gt;20%-40% for six of the 14 eruptions analyzed. Such high values argue against current CME-shock origin models, predicting a &lt;2% back-precipitation; hence, the computed number of high-energy SEPs appears to be greatly insufficient to sustain the measured γ-ray emission.

Keywords: Solar energetic particles, Solar gamma-ray emission
Thermal Energy Census with the Sunyaev-Zel'dovich Effect of DESI Galaxy Clusters/Groups and Its Implication on the Weak-lensing Power Spectrum. We carry out a thermal energy census of hot baryons at z &lt; 1, by cross correlating the Planck Modified Internal Linear Combination Algorithm (MILCA) y map with 0.8 million clusters/groups selected from the Yang et al. catalog. The thermal Sunyaev-Zel'dovich effect around these clusters/groups is reliably obtained, which enables us to make our model constraints based on one-halo (1h) and two-halo (2h) contributions, respectively. (1) The total measurement signal-to-noise (S/N) of the one-halo term is 63. We constrain the Y-M relation over the halo mass range of 1013-1015 M ⊙ h -1, and find Y ∝ M  α  with α = 1.8 at z = 0.14 (α = 2.1 at z = 0.75). The total thermal energy of gas bound to clusters/groups increases from 0.1 meV cm-3 at z = 0.14 to 0.22 meV cm-3 at z = 0.75. (2) The 2h term is used to constrain the bias-weighted electron pressure &lt;b  y  P  e &gt;. We find that &lt;b  y  P  e &gt; (in units of meV cm-3) increases from 0.24 ± 0.02 at z = 0.14 to 0.45 ± 0.02 at z = 0.75. These results lead to several implications. (i) The hot gas fraction f gas in clusters/groups monotonically increase with the halo mass, where f gas of a 1014 M ⊙ h -1 halo is ~50% (25%) of the cosmic mean at z = 0.14 (0.75). (ii) By comparing the 1h and 2h terms, we obtain a tentative constraint on the thermal energy of unbound gas. (iii) The above results lead to significant suppression of the matter and weak-lensing power spectrum at small scales. These implications are important for astrophysics and cosmology, and we will further investigate them with improved data and gas modeling.

Keywords: Cosmology, Sunyaev-Zeldovich effect, Large-scale structure of the universe
Mass Reconstruction of Galaxy-scale Strong Gravitational Lenses Using a Broken Power-law Model. With mock strong gravitational lensing images, we investigate the performance of the broken power-law (BPL) model proposed by Du et al. (2020) on the mass reconstruction of galaxy-scale lenses. An end-to-end test is carried out, including the creation of mock strong lensing images, the subtraction of lens light, and the reconstruction of lensed images, where the lenses are selected from the galaxies in the Illustris-1 simulation. We notice that, regardless of the adopted mass models (the BPL model or its special cases), the Einstein radius can be robustly determined from imaging data alone, and the median bias is typically less than 1%. Away from the Einstein radius, the lens mass distribution tends to be harder to measure, especially at radii where there are no lensed images detected. We find that, with rigid priors, the BPL model can clearly outperform the single power-law models by achieving &lt;5% median bias on the radial convergence profile within the Einstein radius. As for the source light reconstructions, they are found to be sensitive to both lens light contamination and lens mass models, where the BPL model with rigid priors still performs best when there is no lens light contamination. We show that, by correcting for the projection effect, the BPL model can estimate the aperture and luminosity weighted line-of-sight velocity dispersions to an accuracy of ~6% scatter. These results highlight the great potential of the BPL model in strong lensing related studies.

Keywords: Galaxy dark matter halos, Strong gravitational lensing, Galaxy dynamics, Hubble constant, Galaxy mass distribution, Gravitational lensing, Einstein rings
Early Planet Formation in Embedded Disks (eDisk). VII. Keplerian Disk, Disk Substructure, and Accretion Streamers in the Class 0 Protostar IRAS 16544-1604 in CB 68. We present observations of the Class 0 protostar IRAS 16544-1604 in CB 68 from the "Early Planet Formation in Embedded Disks (eDisk)" ALMA Large program. The ALMA observations target continuum and lines at 1.3 mm with an angular resolution of ~5 au. The continuum image reveals a dusty protostellar disk with a radius of ~30 au seen close to edge-on and asymmetric structures along both the major and minor axes. While the asymmetry along the minor axis can be interpreted as the effect of the dust flaring, the asymmetry along the major axis comes from a real nonaxisymmetric structure. The C18O image cubes clearly show the gas in the disk that follows a Keplerian rotation pattern around a ~0.14 M ☉ central protostar. Furthermore, there are ~1500 au scale streamer-like features of gas connecting from northeast, north-northwest, and northwest to the disk, as well as the bending outflow as seen in the 12CO (2-1) emission. At the apparent landing point of the NE streamer, there is SO (65-54) and SiO (5-4) emission detected. The spatial and velocity structure of the NE streamer can be interpreted as a free-falling gas with a conserved specific angular momentum, and the detection of the SO and SiO emission at the tip of the streamer implies the presence of accretion shocks. Our eDisk observations have unveiled that the Class 0 protostar in CB 68 has a Keplerian-rotating disk with a flaring and nonaxisymmetric structure associated with accretion streamers and outflows.

Keywords: Planet formation, Star formation, Interstellar medium
A Spectral-timing Study of the Inner Flow Geometry in MAXI J1535-571 with Insight-HXMT and NICER. We have performed a spectral-timing analysis of the black hole X-ray binary MAXI J1535-571 during its 2017 outburst, with the aim of exploring the evolution of the inner accretion flow geometry. X-ray reverberation lags are observed in the hard-intermediate state (HIMS) and soft-intermediate state of the outburst. During the HIMS, the characteristic frequency of the reverberation lags ν 0 (the frequency at which the soft lag turns to zero in lag-frequency spectra) increases when the spectrum softens. This reflects a reduction of the spatial distance between the corona and accretion disk, when assuming the measured time lags are associated with the light travel time. We also find a strong correlation between ν 0 and the type-C quasi-periodic oscillation (QPO) centroid frequency ν QPO, which can be well explained by the Lense-Thirring precession model under a truncated disk geometry. Despite the degeneracy in the spectral modeling, our results suggest that the accretion disk is largely truncated in the low hard state, and moves inward as the spectrum softens. Combine the spectral modeling results with the ν 0 - ν QPO evolution, we are inclined to believe that this source probably has a truncated disk geometry in the hard state.

Keywords: Accretion, Black hole physics, X-ray binary stars