Sazuna/UAT_keywords huggingface dataset:
Abundances of Rarely Detected s-process Elements Derived from the Ultraviolet Spectrum of the s-process-enhanced Metal-poor Star HD 196944. We present an analysis of the heavy-element abundances of HD 196944, a carbon-enhanced metal-poor (CEMP) star enriched with elements produced by the slow neutron-capture process (s-process). We obtained a new high-resolution ultraviolet (UV) spectrum of this star, the UV-brightest known CEMP-s star, with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. This spectrum extends deeper into the UV (2029 ≤ λ≤ 2303 Å) than previous studies of any CEMP-s star. When combined with previous UV and optical analysis, a total of 35 elements heavier than zinc (Z = 30) can be detected in HD 196944, and upper limits are available for nine other heavy elements. The abundances can be well fit by models of s-process nucleosynthesis operating in a low-mass companion star that evolved through the asymptotic giant branch phase and transferred heavy elements to HD 196944. This s-process event did not contribute substantially to the Ga, Ge, or As abundances (31 ≤ Z ≤ 33). Our results demonstrate that UV spectroscopy can greatly expand the inventory of heavy elements detectable in CEMP-s stars. ∗Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under NASA contract NAS 5-26555. These observations are associated with programs GO-12554 and GO-14765. This paper also includes data gathered at the McDonald Observatory of The University of Texas at Austin, and the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Ultraviolet astronomy, Stellar abundances, S-process, Nucleosynthesis
Coronal and Chromospheric Dynamics of a Coronal Hole Bright Point. Data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic Magnetic Imager on board the Solar Dynamics Observatory and from the Interface Region Imaging Spectograph, are used to study the evolution at different atmospheric layers of a bright point (BP) in a coronal hole near the network that displays high variability over a period of ∼60 minutes. During this IRIS/AIA interval, there is significant wavelet power in three ranges: ∼6─6.5 minutes (AIA EUV and UV), ∼9─10 minutes (AIA EUV and UV; magnetic field density), and ∼16─17 minutes (EUV). The Mg II k chromospheric flux is modulated by the variations in the BP area and exhibits peak power in the ranges ∼9─10 and 16─17 minutes. The BP is characterized by a complex magnetic structure with a dominant negative-polarity footpoint and three positive-polarity footpoints connected by short extrapolated magnetic field lines. The Mg II k intensity tends to be localized at the footpoints, whereas the coronal emission predominantly occurs at the loop tops. The BP region is mainly redshifted, but the footpoints present Doppler velocities in the ranges −17 to 14 km s−1 (negative polarity) and −12 to 8 km s−1 (positive polarity). For ∼6 minutes, the negative-polarity footpoint shows an upflow, while the positive-polarity footpoints are redshifted. The velocities along the field lines connecting the footpoints, which could serve as a proxy for a low-lying loop, show a gradual variation in orientation and value, suggesting possible plasma propagation along a loop.

Keywords: Solar atmosphere, Solar coronal holes, Solar coronal transients
ORACLE: A Real-time, Hierarchical, Deep Learning Photometric Classifier for the LSST. We present the Online Ranked Astrophysical CLass Estimator (ORACLE), the first hierarchical deep-learning model for real-time, context-aware classification of transient and variable astrophysical phenomena. ORACLE is a recurrent neural network with gated recurrent units, and has been trained using a custom hierarchical cross-entropy loss function to provide high-confidence classifications along an observationally driven taxonomy with as little as a single photometric observation. Contextual information for each object, including host galaxy photometric redshift, offset, ellipticity, and brightness, is concatenated to the light-curve embedding and used to make a final prediction. Training on ∼0.5M events from the Extended LSST Astronomical Time-series Classification Challenge, we achieve a top-level (transient versus variable) macroaveraged precision of 0.96 using only 1 day of photometric observations after the first detection in addition to contextual information, for each event; this increases to &gt;0.99 once 64 days of the light curve has been obtained, and 0.83 at 1024 days after first detection for 19-way classification (including supernova subtypes, active galactic nuclei, variable stars, microlensing events, and kilonovae). We also compare ORACLE with other state-of-the-art classifiers and report comparable performance for the 19-way classification task, in addition to delivering accurate top-level classifications much earlier. The code and model weights used in this work are publicly available at our associated GitHub repository (https://github.com/uiucsn/Astro-ORACLE).

Keywords: Astroinformatics, Computational astronomy, Classification, High energy astrophysics, Astronomy software, Transient sources, Astrostatistics, Stellar classification, Computational methods, Transient detection, Time domain astronomy, Supernovae
Spectropolarimetric Evolution Reveals Dual-axis Ejecta in the Atypical Magnetar-powered SN 2012au. We present six epochs of optical spectropolarimetric observations of the unique and slow-evolving Type Ib supernova (SN) 2012au, between 0 and 295 day post-R-band maximum. The polarization levels seen throughout our observations are on average 0.87% ± 0.05% higher than those of any Type Ib SN yet studied, suggesting either that it is the most asymmetric of the sample or, if all SNe Ib have similar asymmetry, that it is viewed at a more optimum angle. Significant continuum polarization indicates that the photosphere exhibited a global departure from spherical symmetry at the level of 10%−40% at the earliest times (days 0─40), which decreased to 0%−20% by days 57─90. During the early photospheric phase, the ejecta maintained a near-constant orientation of 12°−20° on the sky, as shown by the dominant axis in the Stokes q−u plane. Polarization signatures in the Fe II λλλ4924, 5018, 5169 lines shared this axis. Meanwhile, high levels of polarization associated with the He I lines traced distinct q−u loops with a dramatic rotation away from the dominant axis, indicating that the early time ejecta were also characterized by hot, fast, helium-rich material concentrated near the poles. At day 295, during the transition to the nebular phase, a new, highly elongated structure became prominent in the ejecta, with an axis orthogonal to the dominant axis that defined the photospheric phase. This dual-axis geometry may link SN 2012au's high luminosity and asymmetric structure to a magnetar powering mechanism.

Keywords: Spectropolarimetry, Core-collapse supernovae, Type Ib supernovae, Starlight polarization, Magnetars, Supernovae
Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. I. High-resolution Time-averaged Spectroscopy. We present a high-resolution X-ray spectroscopic study of the narrow-line Seyfert 1 galaxy NGC 4051 using two XMM-Newton high-resolution Reflection Grating Spectrometer observations. The spectra reveal three distinct layers of photoionized gas flowing outward from the central black hole: a low-ionization phase (LIP), a higher-ionization phase (HIP), and a high-velocity and high-ionization phase (HVIP). Each absorber leaves characteristic imprints on the soft X-ray spectrum. While the LIP and HVIP are fully consistent with being in ionization equilibrium with the central radiation field over the course of the ∼250 ks spanned by the two observations, the HIP shows a significant change in ionization (3.8σ), suggesting nonequilibrium. By modeling the two spectra with our time-dependent photoionization code (TEPID), we constrain the density of the HIP gas to  lognH=7.7−0.9+0.2  and estimate its distance to be about  R=0.45−0.09+0.80  lt-day from the black hole, corresponding to  R=4000−800+7000  gravitational radii. In contrast, the narrow soft X-ray emission lines remain constant, consistent with an origin in the more extended narrow-line region. Our results show the value of combining high-resolution and time-resolved spectroscopy to probe the structure, physical conditions, and variability of active galactic nucleus outflows.

Keywords: Active galaxies, Active galactic nuclei, X-ray active galactic nuclei
Determining the State of Jupiter's Magnetosphere Using In Situ and Remote Sensing Observations. While Jupiter's magnetosphere is primarily governed by internal processes, variations in solar wind conditions can significantly modulate magnetospheric energy. Assessing solar wind conditions at Jupiter has been a long-standing challenge in the community. In this study, we investigate multiple datasets, including auroral images captured by the Hubble Space Telescope and in situ measurements obtained by the Juno spacecraft, to characterize Jupiter's magnetosphere during solar wind compression and quiet conditions. The distinct responses demonstrate that auroral morphologies, lobe magnetic fields, ultra-low-frequency waves, and broadband kilometric radio emissions could serve as effective indicators for magnetospheric states. In particular, we statistically analyze the distribution of lobe magnetic fields, which represent the intensities of the cross-field electrical currents in the magnetodisc, and propose the applicability of the lobe magnetic field as a proxy for solar wind conditions. The results from the four individual methods of determining magnetospheric states are generally consistent, providing further evidence of their robustness. These observational proxies for solar wind conditions could therefore be widely applied in both existing spacecraft datasets and those from future missions to Jupiter.

Keywords: Planetary magnetospheres, Solar-planetary interactions, Jupiter
Multiwavelength Observations of the Apparently Nonrepeating FRB 20250316A. The physical origin of fast radio bursts (FRBs) remains uncertain. Although multiwavelength observations have been widely conducted, only Galactic FRB 20200428D is associated with an X-ray burst from the magnetar SGR J1935+2154. Here we present multiwavelength follow-up observations of the nearby bright FRB 20250316A, including the Five-hundred-meter Aperture Spherical radio Telescope (FAST), Einstein Probe (EP) X-ray mission, Chandra X-ray Observatory, Wide Field Survey Telescope (WFST), and Space Variable Objects Monitor/Visible Telescope (SVOM/VT). The 13.08 hr FAST follow-up campaign without pulse detection requires an energy distribution flatter than those of well-known repeating FRBs, suggesting that this burst is likely a one-off event. A prompt EP follow-up and multiepoch observational campaign totaling &gt;100 ks led to the detection of an X-ray source within the angular resolution of its Follow-up X-ray Telescope (FXT; 10″). A subsequent Chandra observation revealed this source to be offset by 7″ from the FRB position and established a 0.5─10 keV flux upper limit of 7.6 × 10−15 erg cm−2 s−1 at the FRB position, corresponding to ∼1039 erg s−1 at the 40 Mpc distance of the host galaxy NGC 4141. These results set one of the most stringent limits on X-ray emission from a nonrepeating FRB, disfavoring ultraluminous X-ray sources as counterparts of apparently one-off FRBs and offering critical insights into afterglow models. Our study suggests that an arcsecond localization of both the FRB and its potential X-ray counterpart is essential for exploring the X-ray counterpart of an FRB.

Keywords: Radio bursts, Transient sources, Radio transient sources
Bridging the Atmospheric Circulations of Hot and Warm Giant Exoplanets. We perform high-resolution atmospheric flow simulations of hot and warm giant exoplanets that are tidally locked. The modeled atmospheres are representative of those on KELT-11 b and WASP-39 b, which possess markedly different equilibrium temperatures but reside in a similar dynamical regime. In this regime, their key dynamical numbers (e.g., Rossby and Froude numbers) are comparable. Despite their temperature difference, both planets exhibit qualitatively similar atmospheric circulation patterns, which are characterized by turbulent equatorial flows, anticyclonic polar vortices, and large-scale Rossby waves that give rise to quasi-zonal flows in the extratropics (i.e., near ±20∘). Quantitative differences between the KELT-11 b and WASP-39 b atmospheres are consistent with their different Rossby deformation scales, which influence the horizontal length scale of wave─vortex interactions and the overall structure of the circulation.

Keywords: Hydrodynamical simulations, Exoplanets, Hot Jupiters, Exoplanet atmospheric dynamics, Hydrodynamics, Exoplanet atmospheric variability, Planetary atmospheres, Planetary climates, Atmospheric dynamics, Exoplanet atmospheres
Energy Flow and Radiation Efficiency in Radiative GRMHD Simulations of Neutron Star Ultraluminous X-Ray Sources. We investigate numerically the energy flow and radiation efficiency of accreting neutron stars as potential ultraluminous X-ray sources (ULXs). We perform 10 simulations in radiative general relativistic magnetohydrodynamics, exploring six different magnetic dipole strengths ranging from 10 to 100 GigaGauss, along with three accretion rates, 100, 300, and 1000 Eddington luminosity units. Our results show that the energy efficiency in simulations with a strong magnetic dipole of 100 GigaGauss is approximately half that of simulations with a magnetic dipole an order of magnitude weaker. Consequently, radiation efficiency is lower in simulations with stronger magnetic dipoles. We also demonstrate that outflow power increases as the magnetic dipole weakens, resulting in stronger beaming in simulations with weaker magnetic dipoles. As a result of beaming, simulations with magnetic dipole strengths below 30 GigaGauss exhibit apparent luminosities consistent with those observed in ULXs. As for the accretion rates, we find that higher accretion rates lead to more powerful outflows, higher kinetic efficiency, and lower radiation efficiency compared to those of lower accretion rate simulations.

Keywords: Neutron stars, Stellar accretion disks, High energy astrophysics, Magnetohydrodynamical simulations
All-sky Neutrino Point-source Search with IceCube Combined Track and Cascade Data. Despite extensive efforts, discovery of high-energy astrophysical neutrino sources remains elusive. We present an event-level simultaneous maximum likelihood analysis of tracks and cascades using IceCube data collected from 2008 April 6 to 2022 May 23 to search the whole sky for neutrino sources, and using a source catalog, for coincidence of neutrino emission with gamma-ray emission. This is the first time a simultaneous fit of different detection channels is used to conduct a time-integrated all-sky scan with IceCube. Combining all-sky tracks, with superior pointing power and sensitivity in the northern sky, with all-sky cascades, with good energy resolution and sensitivity in the southern sky, we have developed the most sensitive point-source search to date by IceCube that targets the entire sky. The most significant point in the northern sky aligns with NGC 1068, a Seyfert II galaxy, which, from the catalog search, shows a 3.5σ excess over background after accounting for trials. The most significant point in the southern sky does not align with any source in the catalog and is not significant after accounting for trials. A search for the single most significant Gaussian flare at the locations of NGC 1068, PKS 1424+240, and the southern highest-significance point shows results consistent with expectations for steady emission. Notably, this is the first time that a flare shorter than four years has been excluded as being responsible for NGC 1068's emergence as a neutrino source. Our results show that combining tracks and cascades when conducting neutrino source searches improves sensitivity and can lead to new discoveries.

Keywords: Particle astrophysics, Neutrino astronomy, High energy astrophysics
Kinematically Complex Circumgalactic Gas Around a Low-mass Galaxy: Filamentary Inflow and Counterrotation in J0910b. We present the first detailed, spatially resolved study of the circumgalactic medium (CGM) surrounding the low-mass, low-redshift star-forming galaxy J0910b (SDSS J091458.61+110845.1; M⋆ ∼ 109.2 M⊙, z = 0.096), focusing on its gas dynamics, ionization mechanisms, and kinematics. J0910b is the lowest-mass galaxy in our low-redshift CGM survey using the Keck Cosmic Web Imager (KCWI). Using KCWI integral field spectroscopy and CLOUDY modeling, we map the ionization structure and velocity field of the CGM through Hα, [O III] λ5007, and [O II] λλ3727, 3729 emission. We detect a predominantly cool (T ∼ 104 K) ionized halo extending to ∼35 kpc (∼0.35 Rvir), with a complex structure including a counterrotating component and two filamentary inflows. The counterrotating CGM contains ∼7.4 × 109 M⊙ of ionized gas—nearly 5 times the stellar mass—and exhibits a positive radial metallicity gradient, rising from 0.2 Z⊙ at 9 kpc to 0.65 Z⊙ at 16 kpc. Velocity dispersion maps reveal a shell-like structure near the interstellar medium-CGM interface, suggesting feedback-driven outflows that redistributed enriched gas. In contrast, the filaments show low metallicities (∼0.07 Z⊙), high specific angular momentum (j ∼ 3.7 × 103 kpc km s−1), and an accretion rate of 0.05 M⊙ yr−1, consistent with an intergalactic origin. Together, these components reveal a dynamically rich CGM. The counterrotating gas dominates the halo's mass, accounts for ∼33% of the cosmic baryon budget, and must be continuously replenished (tcool ∼ 0.3─2 Myr). These results suggest a long-lived, regulated CGM that governs star formation through angular momentum exchange and gas recycling.

Keywords: Star formation, Galaxy evolution, Circumgalactic medium
A Multiwavelength View of ρ Oph. I. Resolving the X-Ray Source between A and B. We present a multiwavelength analysis of the central stellar pair of ρ Oph components A and B. Using recent high-resolution Chandra X-ray Observatory observations, we demonstrate with high confidence that the dominant X-ray source is ρ Oph B, while ρ Oph A is comparatively X-ray faint. This result contrasts with earlier XMM-Newton observations, which, due to limited spatial resolutions, attributed the X-ray emission to ρ Oph A. An analysis of ρ Oph B's X-ray light curves and spectra reveals properties more consistent with a cool star than a hot star. We therefore propose that ρ Oph B is an Algol-like binary system, consisting of a B-type primary and an active, X-ray-emitting GK-type companion.

Keywords: Stellar astronomy, Astrometry, High energy astrophysics
New Symbiotic Stars or Candidates in LAMOST Low-resolution Spectra. Symbiotic stars are among the most important binary systems for studying binary star interactions and Type Ia supernova progenitors. Based on the unique observational characteristics of symbiotic stars—strong H I and He I emission lines, giant spectral features, and the presence of [O III], He II, O VI, and other emission lines with ionization potentials exceeding 35 eV—and the Gaia information, we search for new symbiotic stars using the low-resolution spectroscopic survey data from LAMOST. Thirty-six binary systems have been selected as symbiotic stars or candidates, including the five known symbiotic stars. Among them, five systems (ZTF J005917.52+315605.4, ATO J094137.5+075304, LAMOST J200310.90+360822.6, LAMOST J072528.18+342530.4, and V* V758 Cyg) have been found as new symbiotic stars. Notably, LAMOST J072528.18+342530.4 and V* V758 Cyg were also confirmed as new symbiotic stars in a recent study. For the remaining 26 candidates, classification is based solely on the presence of [O III] emission lines (with ionization potentials &gt;35 eV) and the absence of He II high-excitation emission lines. Further observations are needed to confirm their nature as symbiotic stars.

Keywords: Spectroscopic binary stars, Symbiotic binary stars, Stellar spectral lines
StarStream: Automatic Detection Algorithm for Stellar Streams. The Gaia mission has led to the discovery of over 100 stellar streams in the Milky Way, most of which likely originated from globular clusters (GCs). As the upcoming wide-field surveys can potentially continue to increase the number of known streams, there is a growing need to shift focus from manual detection of individual streams to automated detection methods that prioritize both quality and quantity. Traditional techniques rely heavily on the visual expectation that GC streams are dynamically cold and thin. This assumption does not hold for all streams, whose morphologies and kinematics can vary significantly with the progenitor's mass and orbit. As a result, these methods are biased toward a subset of the whole stream population, with often unquantified purity and completeness. In this work, we present StarStream, an automatic stream detection algorithm based on a physics-inspired model rather than visual expectation. Our method provides a more accurate prediction of stream stars in the multidimensional space of observables, while using fewer free parameters to account for the diversity of streams. Applied to a mock GC stream catalog tailored for the Gaia DR3 data set, our algorithm achieves both purity and completeness of at least 65% at Galactic latitudes ∣b∣ &gt; 30∘.

Keywords: Globular star clusters, Galaxy dynamics, Stellar dynamics, Stellar streams
Measuring Dust Masses of Protoplanetary Disks in Serpens and L1641/L1647 with ALMA. Protoplanetary disks are an essential component of the planet formation process. The amount of dust and gas in the disk constrains the number and size of planets that can form in a system. We analyze 178 T Tauri stars, 18 in Serpens and 160 in L1641/L1647, and measure their disk dust masses using spectral energy distribution modeling and multiwavelength data, including 1.3 mm (ALMA band 6) fluxes from the literature. The disk masses calculated in this work are up to ∼2 times higher than those previously reported. We conclude that this is because disks may be partially optically thick at millimeter wavelengths, while most calculations of the disk mass assume that the disk is optically thin at 1.3 mm. We calculate optical depths at 1.3 and 7 mm for a subset of the Serpens and L1641/L1647 disk sample and show that the vast majority of disks become optically thin at longer millimeter wavelengths; thus, observations at 7 mm (i.e., ALMA band 1) are vital to better characterize disk dust masses.

Keywords: Planetary system formation, T Tauri stars, Stellar accretion disks, Protoplanetary disks