Sazuna/UAT_keywords huggingface dataset:
A Time-dependent Spectral Analysis of γ Cassiopeiae. We investigated the temporal and spectral features of γ Cassiopeiae's X-ray emission within the context of the white dwarf (WD) accretion hypothesis. We find that the variabilities present in the X-ray data show two different signals, one primarily due to absorption and the other due to flickering like in nonmagnetic cataclysmic variables. We then use this two-component insight to investigate previously unreported simultaneous XMM and NuSTAR data. The results of model fitting find WD properties consistent with optical studies alongside a significant secondary, thermal source. We propose a secondary shock between the Be decretion disk and WD accretion disk as the source. Finally, we analyzed a unique, low-count-rate event of the XMM light curve as potential evidence for the WD encountering Be decretion disk structures.

Keywords: X-ray astronomy, High resolution spectroscopy, Gamma Cassiopeiae stars, White dwarf stars, Early-type emission stars, Be stars
A Systematic Search for Redback and Black Widow Candidates Based on the 4FGL-DR3 Unassociated Sources and the Zwicky Transient Facility Data. Spider pulsars represent a unique subclass of radio millisecond pulsars in binaries, and are further categorized into black widows and redbacks according to the mass of the low-mass companion. These pulsars, observable across multiple wavelengths, exhibit periodic variability in optical. The discovery and study of additional spider-type pulsars are crucial for a fuller understanding the evolution of binary stars in close orbits and the recycling theory of millisecond pulsars. In this work, we systematically searched for spider pulsar binary systems using time-domain variability data from the Zwicky Transient Facility and unassociated gamma-ray sources from the Fermi 4FGL-DR3 catalog. We developed a time-domain data processing pipeline that employs the Lomb–Scargle periodogram algorithm. As a result, we identified a total of 194 ellipsoidal variables and irradiation-type binary stars. Further refinement using the Gaia Hertzsprung–Russell diagram resulted in a selection of 24 spider pulsar candidates. Incorporating the 4FGL 95% confidence error ellipse reduced the sample to 19 candidates. An additional filter using the Gaia color-reduced proper motion diagram yielded nine "gold sample" candidates. These newly identified spider pulsar candidates will guide future observational campaigns in radio, X-ray, and optical spectroscopy, aiding in the comprehensive validation of their nature.

Keywords: Millisecond pulsars, Gamma-ray sources, Pulsars, Ellipsoidal variable stars, Binary pulsars
C3PO. III. On the Lithium Signatures following Planet Engulfment by Stars. Planet engulfment has been identified as one of the mechanisms for enhancing lithium abundance in stars. However, comprehensive investigations into lithium signatures following such events remain limited. Stars born together, sharing a common origin and stellar characteristics, provide a unique opportunity to study these signatures and compare lithium abundances. We demonstrate that the distinctive signature of planet engulfment in lithium abundance is only discernible among highly similar stellar twins. We present lithium abundance measurements for 125 comoving pairs of stars, representing the largest sample to date with a single, homogeneous assessment of high-precision lithium abundance. While lithium abundance enhancements in pairs showing planet engulfment signatures are within 0.35 dex, we find that even at fixed stellar parameters (temperature and age), the intrinsic scatter in lithium abundance is typically 0.35 dex for G/F dwarfs and can be as large as 0.6 dex for older and cooler stars due to internal stellar evolution processes. Since the planet engulfment signature from lithium can be masked by stellar intrinsic scatter, our findings raise questions about relying solely on lithium as an indicator for planet engulfment or attributing lithium-richness in stars primarily to planet engulfment events.

Keywords: Main sequence stars, Star-planet interactions, Chemical abundances, Exoplanets
JWST Early Release Science Program TEMPLATES: Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation. This paper gives an overview of Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star formation (TEMPLATES), a JWST Early Release Science program that targeted four extremely bright, gravitationally lensed galaxies, two extremely dusty and two with low attenuation, as templates for galaxy evolution studies with JWST. TEMPLATES obtains a common set of spectral diagnostics for these 1.3 ≤ z ≤ 4.2 galaxies, in particular Hα, Paschen α, and the rest-frame optical and near-infrared continua. In addition, two of the four targets have JWST coverage of [O III] 5007 Å and Hβ; the other two targets have JWST coverage of polycyclic aromatic hydrocarbon 3.3 μm and complementary Atacama Large Millimeter/submillimeter Array data covering the [C II] 158 μm emission line. The science goals of TEMPLATES are to demonstrate attenuation-robust diagnostics of star formation, map the distribution of star formation, compare the young and old stellar populations, and measure the physical conditions of star formation and their spatial variation across the galaxies. In addition, TEMPLATES has the technical goal to establish best practices for the integral field units within the NIRSpec and MIRI instruments, both in terms of observing strategy and in terms of data reduction. The paper describes TEMPLATES's observing program, scientific and technical goals, data reduction methods, and deliverables, including high-level data products and data reduction cookbooks.

Keywords: Starburst galaxies, Astronomy software, Strong gravitational lensing, James Webb Space Telescope, Extragalactic astronomy
Electrostatic Transport Characteristics of Olivine Particles under Electron Irradiation in Vacuum. Electrostatic dust transport on airless planetary bodies, such as the Moon, plays a crucial role in shaping their surface environment and influencing the evolution of surface materials. To investigate the effects of electron irradiation on the transport characteristics of micron-sized dust particles under simulated lunar conditions, we measured the diameters and velocities of moving olivine particles using a laser Doppler system. Experiments were conducted under electron irradiation with energies up to 500 eV and currents ranging from 1 to 500 μA. The results demonstrate a strong dependence of electrostatic dust migration on the incident electrons' energy and current, with more pronounced effects observed at higher energies. This offers insights into the mechanisms behind localized dust migration during magnetic tail crossings and in the lunar terminal/polar plasma wakes, where electrostatic charging likely plays a key role. However, further observations are necessary to verify these phenomena fully. Olivine particles exhibited significantly higher transport rates than anorthite particles under the same conditions, confirming the distinct transport characteristics of various dust components. Furthermore, based on the patched charge model, we examined the driving force and initial vertical velocity distribution to better understand the mechanisms behind dust lofting. These findings provide valuable insights into dust transport mechanisms on airless planetary surfaces, with implications for future space exploration missions and environmental modeling.

Keywords: Lunar surface, Dust composition, Electron impact excitation, Interstellar dust processes
Finding the Fuse: Prospects for the Detection and Characterization of Hydrogen-rich Core-collapse Supernova Precursor Emission with the LSST. Enhanced emission in the months to years preceding explosion has been detected for several core-collapse supernovae (SNe). Though the physical mechanisms driving the emission remain hotly debated, the light curves of detected events show long-lived (≥50 days), plateau-like behavior, suggesting hydrogen recombination may significantly contribute to the total energy budget. The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will provide a decade-long photometric baseline to search for this emission, both in binned pre-explosion observations after an SN is detected and in single-visit observations prior to the SN explosion. In anticipation of these searches, we simulate a range of eruptive precursor models to core-collapse SNe and forecast the discovery rates of these phenomena in LSST data. We find a detection rate of ∼40–130 yr‑1 for SN IIP/IIL precursors and ∼110 yr‑1 for SN IIn precursors in single-epoch photometry. Considering the first three years of observations with the effects of rolling and observing triplets included, this number grows to a total of 150–400 in binned photometry, with the highest number recovered when binning in 100 day bins for 2020tlf-like precursors and in 20 day bins for other recombination-driven models from the literature. We quantify the impact of using templates contaminated by residual light (from either long-lived or separate precursor emission) on these detection rates, and explore strategies for estimating baseline flux to mitigate these issues. Spectroscopic follow-up of the eruptions preceding core-collapse SNe and detected with LSST will offer important clues to the underlying drivers of terminal-stage mass loss in massive stars.

Keywords: Sky surveys, Core-collapse supernovae, Stellar mass loss
Bird's-eye View of Molecular Gas across Stephan's Quintet Galaxy Group and Intragroup Medium. We present the large-scale distribution and kinematics of cold molecular gas across the compact galaxy group Stephan's Quintet, based on CO(2–1) observations performed with the Atacama Compact Array (ACA) and CO(1–0) data from the Combined Array for Research in Millimeter-wave Astronomy (CARMA). We find coherent structures of molecular gas associated with the galaxies and intragroup medium, which follow the distribution of warm H2 previously seen with the James Webb Space Telescope (JWST). CO is associated with a ridge of shocked gas that crosses the galaxy group, and with a spiral arm of the intruding galaxy NGC 7318b, which interacts with the intragroup medium along the ridge. Although the ridge contains widespread shocks, turbulent gas, and warm H2, the CO lines are narrower than elsewhere in Stephan's Quintet (FWHM ∼ 25–65 km s‑1), indicative of settled cold gas. At a distinctly different velocity, CO is found in the active galaxy NGC 7319 and northern star-forming region SQ-A. A bridge of turbulent molecular gas connects NGC 7319 with the ridge, covering a gap of ∼700 km s‑1 between these structures. The gas excitation ranges from  /  ∼ 0.3 in the bridge and SQ-A, to ∼0.5 along the ridge, to near unity in the center of NGC 7319. We also detect either a molecular outflow or turbulent molecular gas associated with the radio source in NGC 7319. These ACA data are part of a program with the Atacama Large Millimeter/submillimeter Array and JWST to study the physics of molecular gas from the largest to the smallest scales across the intragroup medium of Stephan's Quintet.

Keywords: Hickson compact group, Galaxy collisions, Millimeter astronomy, Circumgalactic medium, Radio galaxies, Radio telescopes, Galaxy groups, Intergalactic medium, Shocks, Interacting galaxies, Intergalactic filaments
Spectroscopic Modeling of Luminous Transients Powered by H-rich and He-rich Circumstellar Interaction. In this study, we perform detailed spectroscopic modeling to analyze the interaction of circumstellar material (CSM) with ejecta in both hydrogen-rich and hydrogen-poor superluminous supernovae (SLSNe), by systematically varying properties such as the CSM density, composition, and geometry to explore their effects on spectral lines and light-curve evolution. Using advanced radiative transfer simulations with the new, open-source SuperLite code to generate synthetic spectra, we identify key spectroscopic indicators of CSM characteristics. Our findings demonstrate that spectral lines of hydrogen and helium exhibit significant variations due to differences in CSM mass and composition. In hydrogen-rich Type II SLSNe, we observe pronounced hydrogen emission lines that correlate strongly with a dense, extended CSM, suggesting massive, eruptive mass-loss histories. Conversely, in hydrogen-poor SLSNe, we recover mostly featureless spectra at early times, with weak hydrogen lines appearing only in the very early phases of the explosion, highlighting the quick ionization of traces of hydrogen present in the CSM. We analyze the properties of the resulting emission lines, particularly H α  and H β , for our models using sophisticated statistical methods. This analysis reveals how variations in the SN progenitor and CSM properties can lead to distinct spectroscopic evolutions over time. These temporal changes provide crucial insights into the underlying physics driving the explosion and the subsequent interaction with the CSM. By linking these spectroscopic observations to the initial properties of the progenitor and its surrounding material, our study offers a useful tool for probing the pre-explosion histories of these explosive events.

Keywords: Stellar-interstellar interactions, Monte Carlo methods, Transient sources, Circumstellar shells, Radiative transfer, Supernovae
Virgo Filaments. IV. Using WISE to Measure the Modification of Star-forming Disks in the Extended Regions Around the Virgo Cluster. Recent theoretical work and targeted observational studies suggest that filaments are sites of galaxy preprocessing. The aim of the WISESize project is to directly probe galaxies over the full range of environments to quantify and characterize extrinsic galaxy quenching in the local universe. In this paper, we use GALFIT to measure the IR 12 μm (R 12) and 3.4 μm (R 3.4) effective radii of 603 late-type galaxies in and surrounding the Virgo cluster. We find that Virgo cluster galaxies show smaller star-forming disks relative to their field counterparts at the 2.5σ level, while filament galaxies show smaller star-forming disks to almost 1.5σ. Our data, therefore, show that cluster galaxies experience significant effects on their star-forming disks prior to their final quenching period. There is also tentative support for the hypothesis that galaxies are preprocessed in filamentary regions surrounding clusters. On the other hand, galaxies belonging to rich groups and poor groups do not differ significantly from those in the field. We additionally find hints of a positive correlation between stellar mass and size ratio for both rich group and filament galaxies, though the uncertainties on these data are consistent with no correlation. We compare our size measurements with the predictions from two variants of a state-of-the-art semi-analytic model (SAM), one which includes starvation and the other incorporating both starvation and ram pressure stripping (RPS). Our data appear to disfavor the SAM, which includes RPS for the rich group, filament, and cluster samples, which contributes to improved constraints for general models of galaxy quenching.

Keywords: Galaxy environments, Galactic and extragalactic astronomy, Galaxy evolution, Extragalactic astronomy, Galaxy quenching, Galaxy processes
A Search for Asymmetric Kinematic Components in Circumstellar Envelopes Using OH Main Line Masers. Circumstellar OH maser lines are useful for studying the dynamics of the circumstellar envelope (CSE) around evolved stars. This study aims to identify CSEs around cold stars, which exhibit deviations from the spherical expansion, by comparing the velocity ranges of the OH main lines (1665/1667 MHz) with those of the satellite line (1612 MHz), using a database of circumstellar OH maser sources. We performed this comparison for 377 circumstellar OH maser sources. In addition, using infrared two-color diagrams, we examined the evolutionary stages and infrared properties of objects showing velocity excess (velocity excess means the detection of the main lines outside the velocity range of the satellite line). A periodicity analysis of the Wide-field Infrared Survey Explorer (WISE) light curves was also carried out. As a result of the velocity range comparison, eight circumstellar OH maser sources were found to exhibit velocity excess. The infrared colors of these objects match those of postasymptotic giant branch (AGB) stars. Periodic variations were observed in the WISE light curves of five of these eight objects. The results suggest that examining the velocity excess of the main lines relative to the satellite line is scientifically significant because mainline masers probe the CSE dynamics over a broader range of evolutionary stages compared to the 22.235 GHz H2O maser line. Additionally, during the post-AGB phase, the emission regions of the mainline and 22.235 GHz H2O masers may overlap in a CSE, whereas they originate from different regions during the AGB phase.

Keywords: Circumstellar envelopes, Astrophysical masers
Combining Direct Black Hole Mass Measurements and Spatially Resolved Stellar Kinematics to Calibrate the M <SUB>BH</SUB>─σ <SUB>⋆</SUB> Relation of Active Galaxies. The origin of the tight scaling relation between the mass of supermassive black holes (SMBHs; M BH) and their host-galaxy properties remains unclear. Active galactic nuclei (AGNs) probe phases of ongoing SMBH growth and offer the only opportunity to measure M BH beyond the local Universe. However, determining an AGN's host galaxy's stellar velocity dispersion, σ ⋆, and its galaxy dynamical mass, M dyn, is complicated by AGN contamination, aperture effects, and different host-galaxy morphologies. We select a sample of AGNs for which M BH has been independently determined to high accuracy by state-of-the-art techniques: dynamical modeling of the reverberation signal and spatially resolving the broad-line region with the Very Large Telescope Interferometer/GRAVITY. Using integral-field spectroscopic observations, we spatially map the host-galaxy stellar kinematics across the galaxy and bulge effective radii. We find that the dynamically hot component of galaxy disks correlates with M BH; however, the correlations are tightest for aperture-integrated σ ⋆ measured across the bulge. Accounting for the different M BH distributions, we demonstrate—for the first time—that AGNs follow the same M BH─σ ⋆ and M BH─M bulge,dyn relations as quiescent galaxies. We confirm that the classical approach of determining the virial factor as a sample average, yielding  , is consistent with the average f from individual measurements. The similarity between the underlying scaling relations of AGNs and quiescent galaxies implies that the current AGN phase is too short to have altered black hole masses on a population level. These results strengthen the local calibration of f for measuring single-epoch M BH in the distant Universe.

Keywords: AGN host galaxies, Supermassive black holes, Black hole physics, Active galaxies, Scaling relations, Seyfert galaxies, Active galactic nuclei, Galaxy evolution
Multiple Rebrightenings in the Optical Afterglow of GRB 210731A: Evidence for an Asymmetric Jet. The broadband afterglow of gamma-ray bursts (GRBs) is usually believed to originate from the synchrotron radiation of electrons accelerated by the external shock of relativistic jets. Therefore, the jet structure should have a significant impact on the GRB afterglow features. The latest observations indicate that the GRB jets may possess intricate structures, such as Gaussian structure, power-law structure, or jet-cocoon structure. Most recently, an abnormal afterglow of GRB 210731A has raised extensive attention, whose optical afterglow exhibits multiple rebrightening phenomena within 4 hr, posing a serious challenge to the standard afterglow model. Here we intend to interpret the characteristics of GRB 210731A afterglows within the framework of nonaxisymmetric structured jets, where multiple distinct peaks in the afterglow light curve are caused by the uneven distribution of energy and velocity within the jet in the azimuth angle direction. Through Markov Chain Monte Carlo fitting, we show that a three-component asymmetric structured jet can well explain the multiband afterglow data. The energy difference among the three components is about 2.3 orders of magnitude, with higher-energy components exhibiting faster speeds. The radiation contribution of each component has sequentially dominated the light curve of the afterglow, resulting in multiple peaks, with the highest peak occurring at the latest time. We suggest that in the future, polarization observations should be conducted on afterglows with multiple brightening signatures, which will help to effectively distinguish the structured jet model from other alternative models, such as energy injection, and ultimately help to determine the true configuration of jets.

Keywords: Gamma-ray bursts
Extending the ALMA Census of Circumstellar Disks in the Upper Scorpius OB Association. We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 continuum (340 GHz) and carbon monoxide (CO) J = 3–2 observations for an extended sample of disks in the Upper Scorpius OB Association (Upper Sco, age ∼10 Myr). The targets were selected from previous studies that identified new members of Upper Sco using photometry and astrometry from the Gaia mission, and the presence of a disk has been inferred from mid-infrared excess emission. The new ALMA observations are combined with previous ALMA data to define a sample of 202 Upper Sco members with disks that have spectral types between G0 and M5.5. Among these sources, 120 (59%) have been detected in the continuum with a signal-to-noise ratio ≥3, and 83 (41%) have been detected in CO J = 3–2. Both the continuum and CO J = 3–2 fluxes show a strong correlation with the spectral type of the central star and the type of disk inferred from the shape of the infrared spectral energy distribution, where disks around earlier-type stars and full disks are more luminous than disks around later-type stars and evolved and debris disks. The median dust continuum luminosity is lower for disks in Upper Sco than in younger regions, as found in previous studies, where the differences are more pronounced in later spectral types (M4–M5) than in earlier spectral types.

Keywords: Circumstellar disks