Sazuna/UAT_keywords huggingface dataset:
SN 2014C: A Metamorphic Supernova Exploded in the Intricate and Hydrogen-rich Surroundings. We present photometric and spectroscopic observations of supernova (SN) SN 2014C, primarily emphasizing the initial month after the explosion at approximately daily intervals. During this time, it was classified as a Type Ib SN exhibiting a notably higher peak luminosity (Lpeak ≈ 4.3 × 1042 erg s‑1), a faster rise to brightness (trise ≈ 11.6 days), and a more gradual dimming (  mag) compared to typical Type Ib SNe. Analysis of the velocity evolution over the first ~20 days after the explosion supports the view that the absorption near 6200 Å is due to high-velocity Hα in the outer layers of the ejecta, indicating the presence of a small amount of hydrogen in the envelope of the progenitor before the explosion. Assuming that the peak luminosity is entirely attributed to radioactive decay, we estimate that 0.14 M⊙ of 56Ni was synthesized in the explosion. However, this amount of nickel could no longer maintain observed brightness approximately 10 days after peak luminosity, suggesting additional energy sources beyond radioactive decay. This supplementary energy likely originates from interaction with the circumstellar medium (CSM). Consequently, the timing of the SN‑CSM interaction in SN 2014C may occur much earlier than the emergence of Type IIn‑like features during the nebular phase.

Keywords: Type Ib supernovae, Supernovae, Core-collapse supernovae
A New Approach to Constraining Properties of Active Galactic Nucleus Host Galaxies by Combining Image and Spectral Energy Distribution Decomposition: Testing upon the M<SUB>BH</SUB>–M<SUB>⋆</SUB> Relation. The outshining light from active galactic nuclei (AGNs) poses significant challenges in studying the properties of AGN host galaxies. To address this issue, we propose a novel approach that combines image decomposition and spectral energy distribution (SED) decomposition to constrain the properties of AGN host galaxies. Image decomposition allows us to disentangle optical flux into AGN and stellar components, thereby providing additional constraints on the SED models to derive a more refined stellar mass. To test the viability of this approach, we obtained a sample of 24 X-ray-selected type I AGNs with redshifts ranging from 0.73 to 2.47. We estimated the stellar masses for our sample and found that our results are generally consistent with earlier estimates based on different methods. Through examining the posterior distribution of stellar masses, we find that our method could derive better-constrained results compared to previous SED decomposition methods. With the derived stellar masses, we further studied the MBH–M⋆ relation of our sample, finding a higher intrinsic scatter in the correlation for our entire sample compared to the local quiescent correlation, which could be caused by a few "black hole monsters" in our sample. We propose that, based on our method, future works could extend to larger samples of high-redshift AGN host galaxies, thereby enhancing our understanding of their properties.

Keywords: Galaxy masses, Active galactic nuclei, Spectral energy distribution, Scaling relations
ALESS-JWST: Joint (Sub)kiloparsec JWST and ALMA Imaging of z ~ 3 Submillimeter Galaxies Reveals Heavily Obscured Bulge Formation Events. We present JWST NIRCam imaging targeting 13 z ~ 3 infrared-luminous (LIR ∼ 5 × 1012L⊙) galaxies from the ALESS survey with uniquely deep, high-resolution (0 08─0 16) Atacama Large Millimeter/submillimeter Array 870 μm imaging. The 2.0─4.4 μm (observed frame) NIRCam imaging reveals the rest-frame near-infrared stellar emission in these submillimeter-selected galaxies at the same (sub)kiloparsec resolution as the 870 μm dust continuum. The newly revealed stellar morphologies show striking similarities with the dust continuum morphologies at 870 μm, with the centers and position angles agreeing for most sources, clearly illustrating that the spatial offsets reported previously between the 870 μm and Hubble Space Telescope morphologies were due to strong differential dust obscuration. The F444W sizes are 78% ± 21% larger than those measured at 870 μm, in contrast to recent results from hydrodynamical simulations that predict larger 870 μm sizes. We report evidence for significant dust obscuration in F444W for the highest-redshift sources, emphasizing the importance of longer-wavelength MIRI imaging. The majority of the sources show evidence that they are undergoing mergers/interactions, including tidal tails/plumes—some of which are also detected at 870 μm. We find a clear correlation between NIRCam colors and 870 μm surface brightness on ∼1 kpc scales, indicating that the galaxies are primarily red due to dust—not stellar age—and we show that the dust structure on ∼kpc scales is broadly similar to that in nearby galaxies. Finally, we find no strong stellar bars in the rest-frame near-infrared, suggesting the extended bar-like features seen at 870 μm are highly obscured and/or gas-dominated structures that are likely early precursors to significant bulge growth.

Keywords: High-redshift galaxies
Characterizing Stellar and Gas Properties in NGC 628: Spatial Distributions, Radial Gradients, and Resolved Scaling Relations. Building on our previous research involving multiwavelength data from UV to IR, we employ spectroscopic observations of ionized gas, as well as neutral hydrogen gas obtained from the Five-hundred Meter Aperture Spherical Telescope (FAST), to explore the intrinsic processes of star formation and chemical enrichment within NGC 628. Our analysis focuses on several key properties, including gas-phase extinction, star formation rate (SFR) surface density, oxygen abundance, and H I mass surface density. The azimuthal distributions of these parameters in relation to the morphological and kinematic features revealed by FAST H I reveal that NGC 628 is an isolated galaxy that has not undergone recent interactions. We observe a mild radial extinction gradient accompanied by a notable dispersion. The SFR surface density also shows a gentle radial gradient, characteristic of typical spiral galaxies. Additionally, we find a negative radial metallicity gradient of ‑0.44 dex  , supporting the "inside-out" scenario of galaxy formation. We investigate the resolved mass–metallicity relation (MZR) and the resolved star formation main sequence (SFMS) alongside their dependences on the physical properties of both ionized and neutral hydrogen gas. Our findings indicate no secondary dependence of the resolved MZR on SFR surface density or H I mass surface density. Furthermore, we observe that gas-phase extinction and the equivalent width of Hα both increase with SFR surface density in the resolved SFMS.

Keywords: Interstellar medium, H II regions, Galaxy evolution, Chemical abundances
The Size of Accretion Disks from Self-consistent X-Ray Spectra and UV/Optical/NIR Photometry Fitting: Applications to ASASSN–14li and HLX–1. We implement a standard thin disk model with the outer disk radius (Rout) as a free parameter, integrating it into a standard X-ray fitting package to enable self-consistent and simultaneous fitting of X-ray spectra and Ultraviolet (UV), Optical, and Near-infrared (NIR) photometry. We apply the model to the late-time data (Δt ≈ 350–1300 days) of the tidal disruption event (TDE) ASASSN–14li. We show that at these late times, the multiwavelength emission of the source can be fully described by a bare compact accretion disk. We obtain a black hole mass (MBH) of  , consistent with host-galaxy scaling relations, and an Rout of 45 ± 13 Rg, consistent with the circularization radius, with possible expansion at the latest epoch. We discuss how simplistic models, such as a single-temperature blackbody fitted to either X-ray spectra or UV/optical photometry, lead to erroneous interpretations of the scale/energetics of TDE emission. We also apply the model to the soft/high state of the intermediate-mass black hole candidate HLX–1. The model fits the full spectral energy distribution (from X-rays to NIR) without needing an additional stellar population component. We investigate how relativistic effects improve our results by implementing a version of the model with full ray tracing calculations in the Kerr metric. For HLX–1, we find   and Rout ≈ few × 103 Rg, in agreement with previous findings. The relativistic model can constrain the inclination (i) of HLX–1 to be 10° ≤ i ≤70°.

Keywords: Accretion, Supermassive black holes, High energy astrophysics, X-ray transient sources, Time domain astronomy
The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array. Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been found in data from the European, Indian, Parkes, and Chinese pulsar timing arrays. This signal has been interpreted as indicative of the presence of a nanohertz stochastic gravitational-wave background (GWB). To explore the internal consistency of this result, we investigate how the recovered signal strength changes as we remove the pulsars one by one from the data set. We calculate the signal strength using the (noise-marginalized) optimal statistic, a frequentist metric designed to measure the correlated excess power in the residuals of the arrival times of the radio pulses. We identify several features emerging from this analysis that were initially unexpected. The significance of these features, however, can only be assessed by comparing the real data to synthetic data sets. After conducting identical analyses on simulated data sets, we do not find anything inconsistent with the presence of a stochastic GWB in the NANOGrav 15 yr data. The methodologies developed here can offer additional tools for application to future, more sensitive data sets. While this analysis provides an internal consistency check of the NANOGrav results, it does not eliminate the necessity for additional investigations that could identify potential systematics or uncover unmodeled physical phenomena in the data.

Keywords: Supermassive black holes, Millisecond pulsars, Gravitational wave astronomy, Gravitational waves, Radio pulsars
Detectability of Self-lensing Flares of White Dwarfs with Compact Companions. Binaries containing compact objects, viewed nearly edge on, can produce periodic brightening events under certain conditions on the masses, radii, and binary separation. Such flares are caused by one object gravitationally lensing another, in what is known as self-lensing flares. We present a simulation tool that efficiently reproduces the main features of self-lensing flares and facilitates a detection sensitivity analysis for various sky surveys. We estimate the detection prospects for a handful of representative surveys when searching for systems of either two white dwarfs or a white dwarf with other compact objects, i.e., neutron stars and black holes. We find only a marginal ability to detect such systems in existing surveys. However, we estimate many such systems could be detectable by surveys in the near future, including the Vera Rubin Legacy Survey of Space and Time (LSST). We provide a quantitative analysis of the detectability of double-compact object self-lensing flares across the landscape of system parameters, and a qualitative discussion of survey and follow-up approaches to distinguish such flares from confounding events, such as stellar flares, satellite glints, and cosmic rays. We estimate 0.3, 3 and 247 double white dwarf systems could be detected by Transiting Exoplanet Survey Satellite, Zwicky Transient Facility, and LSST, respectively. A similar number of systems with a neutron star or black hole companion could be detected, but we caution that the number densities of such binaries is model dependent and so are our detection estimates. Such binaries can be used to constrain models of the end states of binary evolution.

Keywords: Neutron stars, Binary stars, Astronomical simulations, White dwarf stars, Gravitational lensing, Compact objects, Astrophysical black holes
Determining the Nature of IC 10 X-2: A Comprehensive Study of the Optical/IR Emission from an Extragalactic BeHMXB. We present a comprehensive analysis of the optical and infrared (IR) properties of high-mass X-ray binary (HMXB) IC 10 X-2, classified as a supergiant HMXB and superfast X-ray transient by previous work. Our analysis of regular (daily and weekly) observations by both the Zwicky Transient Facility and Las Cumbres Observatory over a 5 yr period indicates both periodic flares and variations in the apparent magnitude and color with a period of ∼26.5 days—likely the orbital period of this binary system. The periodic flaring suggests the stellar companion is a Be star, with flares resulting from increased accretion onto the neutron star (NS) when it enters the stellar decretion disk. The periodic variations in the optical/IR brightness and color likely result from orbital variations in the hydrogen column density along the line of sight or a transient accretion disk around the NS. Lastly, the numerous short-duration episodes where IC 10 X-2 is significantly "redder" or "bluer" than normal likely result from clumps within this system—which can accrete onto the NS (causing IC 10 X-2 to appear bluer) or pass through the line of sight (causing IC 10 X-2 to appear redder). These results substantially increase our understanding of the evolution of this source, which is a significant source of ionizing photons in its host galaxy IC 10, a low-mass, metal-poor starburst galaxy similar in many respects to those thought to be common in the early Universe.

Keywords: High mass x-ray binary stars
Io's SO<SUB>2</SUB> and NaCl Wind Fields from ALMA. We present spatially resolved measurements of SO2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use of Doppler shift measurements in emission spectra obtained with the Atacama Large Millimeter/submillimeter Array between ~346 and 430 GHz (~0.70–0.87 mm), line-of-sight winds up to ~‑100 m s‑1 in the approaching direction and &gt;250 m s‑1 in the receding direction were derived for SO2 at altitudes of ~10–50 km, while NaCl winds consistently reached ~∣150–200∣ m s‑1 in localized regions up to ~30 km above the surface. The wind distributions measured at maximum east and west Jovian elongations and on the sub-Jovian hemisphere pre- and posteclipse were found to be significantly different and complex, corroborating the results of simulations that include surface temperature and frost distribution, volcanic activity, and interactions with the Jovian magnetosphere. Further, the wind speeds of SO2 and NaCl are often inconsistent in direction and magnitude, indicating that the processes that drive the winds for the two molecular species are different and potentially uncoupled; while the SO2 wind field can be explained through a combination of sublimation-driven winds, plasma torus interactions, and plume activity, the NaCl winds appear to be primarily driven by the plasma torus.

Keywords: Natural satellite dynamics, Millimeter astronomy, Molecular spectroscopy, Planetary atmospheres, Millimeter-wave spectroscopy, Natural satellite atmospheres, Atmospheric dynamics, Submillimeter astronomy, Io, Galilean satellites, Radio astronomy, Doppler shift
A Flat-bottomed Buried Crater and Paleo-layered Structures Revealed at the Von Kármán Crater Using Lunar Penetrating Radar. Impact cratering is the most common geological process occurring on terrestrial planets. The morphologies of impact craters reflect not only the impact conditions but the target properties as well. They have been widely used as subsurface probes into regolith thickness and mechanical properties. A population of paleo-buried impact craters has been discovered by recent geophysical investigations of the Moon; however, their morphologies have never been constrained. The lunar penetrating radar onboard the Chang'e-4 rover has offered an unprecedented opportunity to study the morphology of those paleo-buried craters and reveal obscured depositing history. In this study, we have identified a flat-bottomed paleocrater (450 m in diameter; 11.5 m in depth) on an extraterrestrial world and reconstructed its morphology. This discovery reinforces how impacts would modify layered structures, providing additional evidence regarding subsurface interfaces between the paleoregolith layers and the final-stage lava layers, shedding light on similar processes on all planets.

Keywords: Lunar craters, Lunar regolith, The Moon, Radar astronomy, Lunar impacts
A Natural Laboratory for Astrochemistry: The Variable Protostar B335. Emission lines from complex organic molecules in B335 were observed in four epochs, spanning a luminosity burst of about 10 yr duration. The emission lines increased dramatically in intensity as the luminosity increased, but they have decreased only slightly as the luminosity has decreased. This behavior agrees with expectations of rapid sublimation as the dust temperature increases, and of slower freeze-out after the dust temperature drops. Further monitoring of this source, along with detailed chemical models, will exploit this natural laboratory for astrochemistry.

Keywords: Star formation
Supermassive Black Hole Spin Constraints from Polarimetry in an Equatorial Disk Model. The Event Horizon Telescope has released polarized images of the supermassive black holes Messier 87* (M87*) and Sagittarius A* accretion disks. As more images are produced, our understanding of the average polarized emission from near the event horizon improves. In this Letter, we use a semianalytic model for optically thin, equatorial emission near a Kerr black hole to study how spin constraints follow from measurements of the average polarization spiral pitch angle. We focus on the case of M87* and explore how the direct, weakly lensed image spiral is coupled to the strongly lensed indirect image spiral, and how a precise measurement of both provides a powerful spin tracer. We find a generic result that the spin twists the direct and indirect image polarization in opposite directions. Using a grid search over model parameters, we find a strong dependence of the resulting spin constraint on plasma properties near the horizon. Grid constraints suggest that, under reasonable assumptions for the accretion disk, a measurement of the direct and indirect image spiral pitch angles to ±5° yields a dimensionless spin amplitude measurement with uncertainty   for radially infalling models but otherwise provides only weak constraints; an error of 1∘ can reach  . We also find that a well-constrained rotation measure greatly improves spin measurements. Assuming that equatorial velocity and magnetic field are oppositely oriented, we find that the observed M87* polarization pattern favors models with strong radial velocity components, which are close to optimal for future spin measurements.

Keywords: Supermassive black holes, Very long baseline interferometry, Polarimetry
Dark Matter Distinguished by Skewed Microlensing in the "Dragon Arc". Many microlensed stars discovered by JWST closely follow the winding critical curve of A370 along the "Dragon Arc" with mAB &gt; 26.5, which we show comprises asymptotic giant branch stars microlensed by the observed level of diffuse cluster stars, corresponding to ≃1% of the dark matter density. Most events appear along the inner edge of the critical curve, following an asymmetric band of width ≃4.5 kpc that is skewed by ‑0.7 ± 0.2 kpc. This asymmetry, we argue, follows from the parity difference in caustic structure inherent to microlensing that extends to higher magnification in the negative parity regions. This parity difference predicts a modest net shift of ‑0.04 kpc to the inside of the cluster critical curve within a narrower band of ≃1.4 kpc than observed. Adding cold-dark-matter-like subhalos of 106‑8 M⊙ doubles the width, but detections are predicted to favor the outside of the critical curve, where the subhalos generate local Einstein rings, and subhalos inside the critical curve depress the magnification, reducing microlensing. Instead, the density perturbations of "wave dark matter" as a Bose–Einstein condensate (ψDM) can generate a wide band of corrugated critical curves with a large negative asymmetry. We find that a de Broglie wavelength of ≃10 pc reproduces the observed width of 4.5 kpc, with a negative skewness ≃‑0.6 kpc, like the data, corresponding to a boson mass of ≃10‑22 eV, in agreement with dwarf galaxy dynamical estimates. Independently, we also find clear asymmetry in the Jupiter Arc, with 12 microlensed stars lying along the inside of the critical curve, like the Dragon Arc.

Keywords: Gravitational lensing
Measuring the Hubble Constant through the Galaxy Pairwise Peculiar Velocity. The Hubble constant H0, the current expansion rate of the Universe, is one of the most important parameters in cosmology. The cosmic expansion regulates the mutually approaching motion of a pair of celestial objects due to their gravity. Therefore, the mean pairwise peculiar velocity of celestial objects, which quantifies their relative motion, is sensitive to both H0 and the dimensionless total matter density Ωm. Based on this, using the Cosmicflows-4 data, we measured H0 for the first time via the galaxy pairwise velocity in the nonlinear and quasi-linear range. Our results yield H0 = 75.5 ± 1.4 km s‑1 Mpc‑1 and  . The uncertainties of H0 and Ωm can be improved to around 0.6% and 2%, respectively, if the statistical errors become negligible in the future.

Keywords: Hubble constant, N-body simulations, Cosmological parameters
Formation Rate of Quasiperiodic Eruptions in Galactic Nuclei Containing Single and Dual Supermassive Black Holes. Quasiperiodic eruptions (QPEs) are a novel class of transients recently discovered in a few extragalactic nuclei. It has been suggested that a QPE can be produced by a main-sequence star undergoing repeated partial disruptions by the tidal field of a supermassive black hole (SMBH) immediately after getting captured on a tightly bound orbit through the Hills mechanism. In this Letter, we investigate the period-dependent formation rate of QPEs for this scenario, utilizing scattering experiments and the loss-cone theory. We calculate the QPE formation rates in both a single-SMBH and a dual-SMBH system, motivated by the overrepresentation of postmerger galaxies as QPE hosts. We find that for SMBHs of mass 106–107M⊙, most QPEs formed in this scenario have periods longer than ≃ 100 days. A single-SMBH system generally produces QPEs at a negligible rate of 10‑10–10‑8 yr‑1 due to inefficient two-body relaxation. Meanwhile, in a dual-SMBH system, the QPE rate is enhanced by 3–4 orders of magnitude, mainly due to a boosted angular momentum evolution under tidal perturbation from the companion SMBH (galaxy). The QPE rate in a postmerger galactic nucleus hosting two equal-mass SMBHs separated by a few parsecs could reach 10‑6–10‑5 yr‑1. Our results suggest that a nonnegligible fraction (≃10%–90%) of long-period QPEs should come from postmerger galaxies.

Keywords: Supermassive black holes, Binary stars, Tidal disruption, X-ray transient sources, Ultraviolet transient sources