Sazuna/UAT_keywords huggingface dataset:
Quasiperiodic Oscillations and Reflection Feature Evolution in 4U 1630-47 Observed with Insight-HXMT. The Galactic black hole X-ray binary 4U 1630–47 went into a new outburst in 2021 after ∼600 days from its 2020 outburst. We perform a detailed analysis of quasiperiodic oscillations and spectral evolutions during its 2021 outburst based on Insight-HXMT observations. The main science aims to study the reflection features and evolution of this accreting black hole using the observations of detecting quasiperiodic oscillations (QPOs) and quasi-regular modulations (QRMs). The QPOs frequencies evolve from ∼1.6 to 3.6 Hz, and QRMs have low frequencies around 0.05–0.07 Hz. The reflection fraction varies during the outburst and has a positive correlation with the hardness ratio when QPOs are detected. The centroid frequency of QPOs is anticorrelated to the reflection fraction. This is consistent with the prediction of the precessing inner flow model and provides evidence for a geometrical origin of QPOs. The centroid frequency of QRMs also shows an anticorrelation to the reflection fraction, but the hardness ratio shows no relation to the reflection fraction during the period. We suggest that QRMs may have a different origin from QPOs and be caused by instabilities in the corona.

Keywords: Stellar accretion disks, Black hole physics, X-ray binary stars
Unveiling the Cosmic Dance of Repeated Nuclear Transient ASASSN-14ko: Insights from Multiwavelength Observations. ASASSN-14ko is a periodically repeating nuclear transient. We conducted high-cadence, multiwavelength observations of this source, revealing several recurrent early bumps and rebrightenings in its UV/optical light curves. The energy released during these bumps and rebrightenings shows a diminishing trend in recent UV/optical outbursts, which we monitored through multiwavelength observations. These features can be ascribed to the interaction between stream debris and the expanded disk in the repeated partial tidal disruption event. The X-ray light curve exhibits an inverse pattern compared to the UV/optical bands, displaying sporadic outbursts. Furthermore, our observations demonstrate that the blackbody temperature and radius in each outburst increase with the UV/optical luminosity, and such evolution resembles that observed in X-ray quasiperiodic eruptions, distinguishing it from typical tidal disruption events.

Keywords: Black hole physics, Supermassive black holes, Tidal disruption, Accretion
Unified Weak Lensing Constraints on the Evolution of the Mass–X-Ray Luminosity Relation for Galaxy Clusters. Scaling relations between galaxy cluster properties are crucial for understanding cosmology and baryonic physics. Rigorous calibration of the M–LX relation, employing weak lensing mass and consistent statistical methodology, is challenging due to heterogeneous cluster samples. The release of LEGACY imaging data introduced the possibility of unifying the cluster selection. We present the all-sky extension of the CODEX catalog based on LEGACY data and introduce a Bayesian framework for calibrating the X-ray luminosity–mass relation, derived for 100 clusters with weak lensing mass measurements. Using the X-ray luminosity estimates for those clusters from ROSAT All-Sky Survey (RASS) data, we perform a power-law fit to the M–LX relation. Furthermore, taking advantage of the recently released eROSITA data (eRASS1), we assess the impact of point source contamination on cluster fluxes for 42 clusters in the eRASS1 footprint. The RASS fit yields a slope of β = 0.75 ± 0.09, 1.7σ lower than the best self-similar prediction, with marginal evidence for the redshift evolution of the normalization (γ = 0.65 ± 0.43). As for the eRASS1 analysis, the slope is substantially steeper, β = 1.11 ± 0.15, and in further agreement with the prediction of self-similarity. No additional evolution is also seen (γ = 0.004 ± 0.790). While our results provide the practical means for cosmological studies of both RASS and eRASS data, the link to cluster physics is much cleaner after the cluster flux contamination is reduced. We also analyzed the impact of the selection function on calibration, finding that its full modeling is essential.

Keywords: Galaxy clusters, Gravitational lensing, X-ray astronomy, Weak gravitational lensing
What Causes Errors in Wang─Sheeley─Arge Solar Wind Modeling at L1?. Previous ambient solar wind (SW) validation studies have reported on discrepancies between modeled and observed SW conditions at L1. They indicated that a major source of discrepancies stems from how we model the solar corona. Thus, enhancing predictive capabilities demands a thorough examination of coronal modeling. The Wang─Sheeley─Arge (WSA) model has been a workhorse model that provides the near-Sun SW conditions. An important component of it is the potential field source surface model. This study analyzes 15 different Carrington rotations (CRs), and presents a detailed analysis of CR 2052 to identify WSA model settings that lead to successful and erroneous SW predictions at Earth. For the events studied, we show that increasing the model's grid resolution improves the open─close boundary identification. This results in better predicting the onset and duration of high-speed streams (HSSs). In addition, we find an optimized source surface height (Rss) (lying between 1.8 and 3.1 R⊙) further enhances HSS prediction accuracy for the studied events. A detailed analysis shows that changes in Rss (a) change the great circle angular distance maps (at the solar surface) of the associated coronal holes and (b) change the foot-point locations of the magnetic connectivities to the sub-Earth locations. These factors change the near-Sun SW speed, which eventually leads to uncertainties in speeds near Earth. We also investigate the usefulness of coronal hole observations in constraining Rss and SW solutions at Earth, and highlight their underutilized value in guiding the selection of magnetic maps for improved ambient solar wind modeling at L1.

Keywords: Solar wind
Investigating the Physical Properties of Dusty Star-forming Galaxies at z ≳ 1.5 in the GOODS-South Field Using JWST. We investigated how well the physical properties of progenitors of present-day massive spheroidal galaxies (protospheroids) can be constrained by the JWST Advanced Deep Extragalactic Survey (JADES) in the GOODS-South field, which benefits from extensive photometric and spectroscopic data, including those from the Hubble, Spitzer, and Herschel. We adopted a physical model for the evolution of protospheroidal galaxies, which form the bulk of dusty star-forming galaxies (DSFGs) at z ≳ 1.5 and confirmed its consistency with recent mid-infrared high-z galaxy luminosity functions. Using the model and the JADES survey strategy, we simulated a sample of protospheroids over 87.5 arcmin2, matching the JADES/GOODS-S survey area. Photometric redshifts estimated from simulated JWST photometry showed ≳95% accuracy and were used in spectral energy distribution fittings with Code Investigating GALaxy Emission (CIGALE). We demonstrated that JWST will provide reliable stellar mass estimates up to 0.1 dex for the majority of protospheroids at z ≳ 1.5 and can detect low-mass systems during cosmic noon that were inaccessible in the pre-JWST era. Focusing on the active star-forming phase of the protospheroid evolution, we defined a subsample flux limited at 250 μm (DSFG sample) and derived star formation rate, dust luminosity, and dust mass complementing the JWST photometry with that from Spitzer/MIPS and Herschel. We also constructed a JWST-selected DSFG catalog from ASTRODEEP data using NIRCam color criteria and demonstrated strong consistency between the observed and simulated DSFG populations.

Keywords: Starburst galaxies, Galaxy photometry, Galaxy evolution, Spectral energy distribution, Stellar masses, High-redshift galaxies, Galaxies
The Mass of the Vela Pulsar Progenitor and the Age of the Vela-Puppis Complex. The association of the Vela Pulsar with the Vela Supernova Remnant has long supported the hypothesis that core-collapse supernovae yield neutron stars, but its surrounding stellar population now offers new insights into progenitor evolution. By age-dating stars within 150 pc of the Vela Pulsar, we infer properties of its progenitor. These stars belong to the Vela-Puppis complex, revealing the region's star formation history. While stellar population models with standard assumptions suggest a likely progenitor age and mass, these predictions are internally inconsistent with the observed population, indicating that something is missing in the standard modeling approach. With those assumptions, there is very weak support for a ≲10 Myr old population, moderate support for a 40 Myr old population, and strong support for an intermediate-age population around 65–100 Myr old. The ≲10 Myr signal hinges on two peculiar O stars, which are unlike any others in the Vela-Puppis complex and imply nearly three times more main-sequence (MS) stars than are observed. The 40 Myr old population is supported by six red supergiants and several Be stars, but this population is again marginally inconsistent with the observed distribution of MS stars. The red giant and MS distributions are consistent with a 65–100 Myr old population. We discuss several possible resolutions, emphasizing how binary evolution and/or very rapid rotation could resolve these discrepancies. Gaia parallaxes and Stellar Ages enable these results; Stellar Ages is a novel stellar population modeling algorithm that combines individual and population-level age inferences.

Keywords: Stellar associations, Multiple star evolution, Core-collapse supernovae, Pulsars
Magnetic Field Variability as a Consistent Predictor of Solar Flares. Solar flares are intense bursts of electromagnetic radiation that occur due to a rapid destabilization and reconnection of the magnetic field. While preflare signatures and trends have been investigated from magnetic observations prior to flares for decades, analysis that characterizes the variability of the magnetic field in the hours prior to flare onset has not been included in the literature. Here, the 3D magnetic field is modeled using a nonlinear force-free field extrapolation for 6 hr before and 1 hr after 18 on-disk solar flares and flare quiet windows for each active region. Parameters are calculated directly from the magnetic field from two field isolation methods: the "active region field," which isolates field lines where the photospheric field magnitude is ≥200 Gauss, and the "high current region," which isolates field lines in the 3D field where the current, nonpotential field, twist, and shear exceed predefined thresholds. For this small pool of clean events, there is a significant increase in variation starting 2–4 hr before flare onset for the current, twist, shear, and free energy, and the variation continues to increase through the flare start time. The current, twist, shear, and free energy are also significantly stronger through the lower corona and their separation from flare quiet height curves scales with flare strength. Methods are proposed to combine variation of the magnetic fields with variation of other data products prior to flare onset, suggesting a new potential flare prediction capability.

Keywords: Solar flares, Solar physics, Solar coronal mass ejections, Solar corona, Active solar corona
Dynamical Dark Energy in the Crosshairs: A Joint Analysis with DESI, Type Ia Supernovae, and TDCOSMO Constraints. In this work, we perform a comprehensive joint analysis of three representative dark energy models—ΛCDM, the Chevallier─Polarski─Linder (CPL) parameterization, and the Generalized Emergent Dark Energy (GEDE) model—using the latest observational data sets: baryon acoustic oscillation measurements from Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) and 2 (DR2), Type Ia supernovae, and time-delay cosmography from Time-Delay COSMOgraphy (TDCOSMO) lensing. The CPL model yields a statistically significant improvement over ΛCDM, with ∆AIC = −0.54 for DESI DR2+Dark Energy Survey Y5+TDCOSMO, favoring a quintessence-like behavior ( w0=−0.82−0.05+0.05 ,  wa=−0.43−0.31+0.32  at 1σ confidence level). The GEDE model also exhibits slightly favoring than ΛCDM with observations, yielding ∆AIC = −2.15. The captured potential dark energy evolution transition parameter ∆ in GEDE model is constrained to  −0.52−0.20+0.22  (DR1) and  −0.50−0.17+0.18  (DR2), showing a 2.4σ and 2.9σ deviation from zero, respectively. This more than 2σ statistically significant of nonzero value of ∆ provides evidence against a pure cosmological constant scenario. The negative sign indicates quintessence-like behavior (w &gt; −1) in the late universe. Notably, the GEDE constraints show a more than 3σ tension with the ∆ = 1 (Phenomenological Emergent Dark Energy model) predictions. This significant discrepancy implies that while both models belong to the emergent dark energy family, their fundamentally different transition mechanisms lead to distinct cosmological implications. Our results collectively suggest that GEDE provides a phenomenologically viable alternative to ΛCDM.

Keywords: Dark energy, Baryon acoustic oscillations, Cosmological parameters
NuSTAR Analysis of the 2024 Periastron Passage of TeV Binary PSR B1259-63. PSR B1259-63 is a well-studied TeV binary, with an energetic pulsar in orbit around a Be star. Using Nuclear Spectroscopic Telescope Array observations during the 2024 passage of the pulsar through the circumstellar disk, we find the spectrum to be the most energetic (Γ = 1.5) around 27 days after periastron, during the first of two variable, short-term emission episodes of a contemporaneous GeV flare. We discuss the variability in the X-ray flux and the hardening of the spectrum with time, and in the context of previous observations and what that means for the competing energy loss and acceleration timescales.

Keywords: Binary stars, High energy astrophysics, Rotation powered pulsars, Non-thermal radiation sources, Magnetic fields
Synchrotron-limited Particle Acceleration in Relativistic Shearing Flows. Fermi-type shear particle acceleration is a promising mechanism for sustaining ultrarelativistic particles along the kiloparsec scale jets in active galactic nuclei. We explore the possibility of synchrotron-limited electron acceleration in mildly relativistic shearing flows and present numerical solutions to the corresponding particle transport equation. We compare our findings with analytical calculations to infer an effective electron cutoff energy, and discuss the relationship to a simplified box model treatment. The results show that mildly relativistic large-scale jets offer a suitable environment for distributed electron acceleration beyond Lorentz factors of γe ∼ 108.

Keywords: Active galactic nuclei, Relativistic jets, Non-thermal radiation sources, High energy astrophysics
Environmental Evidence for Overly Massive Black Holes in Low-mass Galaxies and a Black Hole–Halo Mass Relation at z ∼ 5. JWST observations have unveiled faint active galactic nuclei (AGNs) at high redshift that provide insights into the formation of supermassive black holes (SMBHs). However, disentangling their stellar from AGN light is challenging. Here, we use an empirical approach to infer the average stellar mass of five faint broad-line (BL) Hα emitters at z = 4–5 with BH masses ≈6 × 106 M⊙, with a method independent of their spectral energy distribution (SED). We use the deep JWST/NIRcam grism survey "All the Little Things" to measure the overdensities around BL-Hα emitters and around a spectroscopic reference sample of ∼300 galaxies. In our reference sample, we find that megaparsec-scale overdensity correlates with stellar mass. Their large-scale environments suggest that BL-Hα emitters are hosted by galaxies with stellar masses ≈5 × 107 M⊙, ≈40 times lower than those inferred from galaxy-only SED fits. Adding measurements around more luminous z ≈ 6 AGNs, we find tentative correlations between line width, BH mass, and the overdensity, suggestive of a steep BH to halo mass relation. The main implications are (1) when BH masses are taken at face value, we confirm extremely high BH to stellar mass ratios of ≈10%, (2) the galaxies of low stellar mass that host growing SMBHs are in tension with typical hydrodynamical simulations, except those without feedback, (3) a 1% duty cycle implied by the host mass hints at super-Eddington accretion, (4) the masses are at odds with an interpretation of the line broadening in terms of high stellar density, (5) our results imply a luminosity-dependent diversity of galaxy masses, environments, and SEDs among AGN samples.

Keywords: AGN host galaxies, Early universe, Quasars, Emission line galaxies, High-redshift galaxies, Galaxies
Tidal Inflation is Stronger for Misaligned Neptune-sized Planets Than Aligned Ones. Recent observations have revealed an intriguing abundance of polar-orbiting Neptune-sized planets, many of which exhibit unusually inflated radii. While such misaligned orbits point to a complex dynamical history, the connection between their orbital orientations and planetary structures remains poorly understood. In this study, we analyze a sample of 12 misaligned and 12 aligned planets using structure models that incorporate tidal heating. We use various statistical tests to demonstrate—with at least 90% confidence—that misaligned planets experience more tidally induced radius inflation compared to aligned planets. This inflation likely stems from their dynamically active histories, which often place them in close-in, eccentric, and highly inclined orbits. We further present a case study of WASP-107 b, an exceptionally inflated polar Neptune, and model its history using a simple coupled orbital and radius evolution approach. Our results place constraints on the planet's tidal quality factor that agree with recent JWST observations.

Keywords: Exoplanet dynamics, Hot Neptunes, Exoplanet tides, Exoplanets
The Coupling and Evolution of Kelvin–Helmholtz and Rayleigh–Taylor Instabilities in the Heliosheath. The shape and structure of the heliosphere remain subjects of ongoing debate, with current models differing on how far the heliospheric jets that form the two-lobe structure extend down the heliotail and whether the surrounding interstellar medium can penetrate the region between the lobes. Rayleigh–Taylor (RT) and Kelvin–Helmholtz (KH) instabilities along the axis of the heliospheric jets have been proposed as key drivers of turbulence in the heliosheath (HS). In this work, we present results from 225 yr MHD simulations that reveal periodic variations in solar wind speed and magnetic field within the HS, coinciding with the cyclic growth of RT and KH instabilities. At the onset of each cycle, the instabilities initially develop simultaneously in the direction normal to the plane of the heliospheric jet, with an average timescale of ∼4.2 yr. As the system evolves over ∼11.1 yr, RT and KH modes decouple, with KH modes subsequently dominating beyond the high-density region and leading to a reduced growth rate, corresponding to a timescale of ∼12.9 yr. These findings suggest that RT and KH instabilities can coevolve and reoccur periodically, contributing to turbulence generation in the HS. Their nonlinear development may play a fundamental role in shaping the large-scale structure of the heliosphere, particularly in the formation and evolution of the open heliospheric tail.

Keywords: Hydrodynamics, Magnetohydrodynamics, Solar wind, Heliosphere
Truncations in the X-Ray Halos of Early-type Galaxies as a Tracer of Feedback and Mergers. The morphology of X-ray halos in early-type galaxies depends on key structure assembly processes, such as feedback and mergers. However, the signatures of these processes are difficult to characterize due to their faint and amorphous nature. We demonstrate that the truncation in the temperature profile of X-ray halos, defined by the radial location of the peak temperature, is significantly more impacted by recent mergers or galaxy interactions than feedback processes. At a fixed stellar mass, a highly asymmetric X-ray halo can be nearly a factor of 10 more truncated than a relaxed one. This analysis led to a discovery of previously unknown asymmetric features in the optical and X-ray halos of three massive galaxies. We detect the intra-group star light and a large ∼45 kpc size stellar stream connected to NGC 0383, suggesting that a recent stellar accretion event has triggered its active galactic nuclei to emit a powerful radio jet. While the disturbed X-ray halo of NGC 1600 is also related to a galaxy-satellite tidal interaction detected in optical imaging, the X-ray shape and asymmetry of NGC 4555 are highly unusual for a galaxy in a low-density environment, requiring further investigation. These results highlight the importance of truncations and deep imaging techniques for untangling the formation of X-ray halos in massive galaxies.

Keywords: Galaxy environments, Scaling relations, Galaxy mergers, Circumgalactic medium, Intracluster medium, Early-type galaxies, Galaxy radii
Figuring Out Gas and Galaxies in Enzo (FOGGIE). IX. The Angular Momentum Evolution of Milky Way─like Galaxies and Their Circumgalactic Gas. We investigate the coevolution of the angular momentum of Milky Way─like galaxies, their circumgalactic gas, and their dark matter halos using zoom-in simulations from the Figuring Out Gas and Galaxies in Enzo suite. We examine how the magnitude and orientation of the angular momentum vary over time within the halo and between the components of mass. From z ∼ 2 to today, and in general across the simulated halos, the specific angular momenta of the central galaxies and the cool gas in their circumgalactic media (T &lt; 105 K) increase together. Over that same period, the specific angular momenta of the hot (&gt;106 K) and dark components of the halo change minimally. By z ∼ 1, the central galaxies have generally lost association with the angular momentum of their full dark matter halo, both in magnitude and orientation. We find a wide distribution of angular momentum orientations in the halo, varying by up to 180° over small (∼tens of kiloparsecs) scales and between the different components of mass. The net angular momenta of the galaxies, their circumgalactic gas, and their dark matter halos are generally misaligned with one another at all cosmic times. The present-day orientation of the central galaxies is established at late times (after z = 1), after the rates of cosmic accretion and mergers decline and the disks are able to settle and stabilize their orientation.

Keywords: Circumgalactic medium
Dust in the Smith Cloud? A UV Investigation into the Smith Cloud's Gas-phase Abundance Patterns. The Smith Cloud is a high-velocity cloud (HVC) on its final approach to the Milky Way that shows evidence of interaction with the Galaxy's disk. We investigate the metallicity and gas-phase chemical depletion patterns in this HVC using UV absorption-line observations toward two background QSOs taken with the Hubble Space Telescope/Cosmic Origin Spectrograph and H I 21 cm emission-line observations taken with Green Bank Telescope. We find evidence of silicon gas-phase depletion with [Si/S] =  −0.72−0.26+0.24  and [Si/O]3σ ≲ −0.05, implying the presence of dust within the Smith Cloud. Because dust is galactic in origin, this HVC could trace the return leg of a Galactic fountain or a dwarf galaxy that passed through the Galactic plane.

Keywords: Interstellar dust, High-velocity clouds, Chemical abundances, Ultraviolet astronomy, Circumgalactic medium