Sazuna/UAT_keywords huggingface dataset:
Characteristics of Inertial Range Turbulent Cascade Rates in the Interplanetary Coronal Mass Ejection. Interplanetary coronal mass ejections (ICMEs) are different from the typical solar wind in their compressibility and levels of fluctuations in magnetic field, proton velocity, density, and temperature, making them a unique environment for studying turbulence properties. However, the difference between cascade rates in the ICMEs and typical solar wind, the comparison between cascade rates estimated by compressible and incompressible models, and how cascade rates in the ICMEs evolve with the radial distance from the Sun are still unclear. Using the data of 33 ICMEs observed between 0.305 au and 1.015 au by Parker Solar Probe and Solar Orbiter, we statistically investigated the incompressible and compressible inertial range turbulent cascade rates (ϵi and ϵc) in and around ICMEs. ϵi and ϵc in the sheaths and ejecta of ICMEs are always larger than in the upstream solar wind before them. ϵi and ϵc in the downstream solar wind behind ICMEs can be amplified after the ICMEs pass. ϵc is always larger than ϵi in all ICME subregions, indicating the amplifying effects of compressibility and levels of fluctuations in proton density, velocity, and temperature on the cascade rates of ICMEs. ϵi and ϵc in all ICME subregions decrease with the increase of the radial distance. These results shed light on our understanding of turbulent cascade rates and their radial evolution in ICMEs.

Keywords: Interplanetary turbulence, Solar wind, Solar coronal mass ejections
A New Hybrid Machine Learning Method for Stellar Parameter Inference. The advent of machine learning (ML) is revolutionary to numerous scientific disciplines, with a growing number of examples in astronomical spectroscopic inference, as ML is more powerful than traditional techniques. Here we introduce a hybrid ML (HML) method combining automatic differentiation, interpolation, and Bayesian optimization to infer stellar parameters of stellar spectra. We study Teff,  , and [Fe/H], but this method could be extended to other parameters such as [α/Fe] (alpha element abundance), C/O (carbon–oxygen ratio), and fsed (sedimentation efficiency). We first use blase to semiempirically recast spectra into sets of Voigt profiles. blase is run on 1314 synthetic spectra from a rectilinear subset of the PHOENIX model grid (Teff: [2300, 12,000] K,  : [2, 6], [Fe/H]: [–0.5, 0], λ: [8038, 12849] Å). For 128,723 detected features, we map stellar parameters to spectral line parameters using linear interpolation. This creates the PHOENIX generator, enabling parallelized spectral synthesis. Gaussian process minimization is used to infer stellar parameters by minimizing a rms loss function. Testing 210 noise-free models (Teff: [3000, 11,000] K,  : [2, 6], [Fe/H]: [‑0.5, 0]), we find inference errors: Teff: 93 K,  : 0.24, and [Fe/H]: 0.056 for Teff &lt; 7000 K, and Teff: 347 K,  : 0.26, and [Fe/H]: 0.16 for Teff ≥ 7000 K. We also upload online an archive of blase models of the PHOENIX subset. This proof-of-concept study shows that semiempirical HML is a viable alternative to traditional approaches in spectroscopic inference.

Keywords: Fundamental parameters of stars, Stellar spectral lines, Stellar atmospheres
X-Ray Polarization Variability during a Few Hz Quasiperiodic Oscillations in Swift J1727.8-1613 Observed with IXPE. We report the polarization properties of low-frequency quasiperiodic oscillations (LFQPOs) observed in Swift J1727.8‑1613 with the Imaging X-ray Polarimetry Explorer (IXPE). LFQPOs have been observed in various objects, but their mechanisms remain unclear despite multiple proposed models. In order to understand the origin of the quasiperiodic oscillation mechanism, we investigated the short time variability of polarized X-rays. We analyzed three data sets of Swift J1727.8‑1613, which were observed during the bright outburst and exhibited the LFQPO by IXPE. We employed a stacking analysis to understand the time variability of polarization during LFQPOs. We found evidence that the polarization degree is higher in the high-flux phase than in the low-flux phase. In addition, the polarization angle during the high-flux phase differed from that during the low-flux phase, although the trend was not entirely the same across the three observations. The variations in spectral hardness and polarization degree correlated with the intensity of LFQPO suggest geometrical changes in the Comptonization region or the involvement of complex Comptonization processes. X-ray polarization observation in wide band provides further understanding of the geometry and magnetic field structure of the accretion flows near the black hole.

Keywords: Low-mass x-ray binary stars, Accretion, Polarimetry, Astrophysical black holes
Mid-infrared Ensemble Variability of Broad-line and Narrow-line Seyfert 1 Galaxies. We utilized multiepoch archival data from the Wide-field Infrared Survey Explorer to compare the variability at 3.4 μm (W1 band) and 4.6 μm (W2 band) of broad-line Seyfert 1 (BLSy1) galaxies and narrow-line Seyfert 1 (NLSy1) galaxies by employing the ensemble structure function (SF). Additionally, we investigated the dependence of mid-infrared (MIR) ensemble SF on common active galactic nucleus parameters. The main results are as follows. (1) The ensemble SF of BLSy1 galaxies is larger than that of NLSy1 galaxies at long rest-frame time lags. (2) The ensemble SFs of BLSy1 galaxies, NLSy1 galaxies, and the combined sample are negatively correlated with the 5100 Å luminosity. The single power-law slope of the ensemble SF is proportional to luminosity. (3) The ensemble SFs of BLSy1 galaxies, NLSy1 galaxies, and the combined sample are negatively correlated with the Eddington ratio and the intensity of the Fe II emission line. The MIR variability of the combined sample is positively correlated with black hole mass and the FWHM of the Hβ emission line at long rest-frame time lags. (4) The long-term MIR variability of the combined sample may be mainly driven by the Eddington ratio. (5) For BLSy1 galaxies, the MIR variability of radio-detected sources is greater than that of radio-undetected sources, whereas for NLSy1 galaxies, the opposite is true.

Keywords: Seyfert galaxies, Active galactic nuclei, Infrared Astronomical Satellite, Infrared photometry
Oligarchic Growth of Protoplanets in Planetesimal Rings. In the standard planet formation scenario, planetesimals are assumed to form throughout the protoplanetary disk and to be smoothly distributed in the radial direction except for the snowline. Planetesimal growth has been investigated using this assumption, and the oligarchic growth model is widely accepted. However, recent simulations of gas and dust evolution have shown that planetesimals form only in radially limited locations, such as at gas pressure bumps and snowlines, and are concentrated in ring-like regions. When planetesimals are distributed in a ring-like region, scattered ones leak from the ring edge, resulting in planetesimal diffusion. To investigate protoplanet growth in expanding planetesimal rings, we perform a series of N-body simulations. In all the simulations, protoplanet growth is well explained by oligarchic growth, while the ring width expands due to planetesimal scattering by the protoplanets. Massive protoplanets tend to form near the ring center, and protoplanets that form far from the ring center are less massive than those in the center. The scaled orbital separations depend on neither the initial ring width nor the total mass, and they are consistent with estimates based on the oligarchic growth model and the diffused planetesimal distribution. The width of the expanded planetesimal ring does not depend on its initial width, but it does depend on its total mass. The maximum mass of protoplanets depends strongly on the total ring mass and weakly on the ring's initial width.

Keywords: Planetary system formation, N-body simulations, Planetesimals, Planetary dynamics, Planet formation
XUE: Thermochemical Modeling Suggests a Compact and Gas-depleted Structure for a Distant, Irradiated Protoplanetary Disk. Unveiling the physical structure of protoplanetary disks is crucial for interpreting the diversity of the exoplanet population. Until recently, the census of the physical properties of protoplanetary disks probed by mid-infrared observations was limited to the solar neighborhood (d ≲ 250 pc). However, nearby star-forming regions (SFRs) such as Taurus—where no O-type stars reside—are not representative of the environments where the majority of the planet formation occurs in the Galaxy. The James Webb Space Telescope (JWST) now enables observations of disks in distant high-mass SFRs, where strong external far-ultraviolet radiation is expected to impact those disks. Nevertheless, a detailed characterization of the population of externally irradiated disks is still lacking. We use the thermochemical code ProDiMo to model JWST/MIRI spectroscopy and archival visual/near-infrared photometry aiming to constrain the physical structure of the irradiated disk around the solar-mass star XUE 1 in NGC 6357 (d ≈ 1690 pc). Our findings are as follows. (1) Mid-infrared dust emission features are explained by amorphous and crystalline silicates with compositions similar to nearby disks. (2) The molecular features detected with MIRI originate within the first ∼1 au, consistent with results from slab models. (3) Our model favors a disk truncated at 10 au with a gas-to-dust ratio of unity in the outskirts. (4) Comparing models of the same disk structure under different irradiation levels, we find that strong external irradiation raises gas temperature tenfold and boosts water abundance beyond 10 au by a factor of 100.

Keywords: Infrared spectroscopy, Star forming regions, Protoplanetary disks, Radiative transfer simulations, Planet formation
Investigating Bidirectional Flows in a Quiescent Prominence Using MAST Ca II 8542 Å Line Scan Observations. Quiescent prominences are large magnetic structures hosting cool plasma in surrounding million-degree solar coronae. Prominences host different flows that may distort magnetic field lines, which may lead to magnetic reconnection inside the prominence body. In this study, we investigate bidirectional flow patches in a quiescent prominence. The investigation included the analysis of velocities in the line of sight (LOS) and the plane of sky (POS) of the prominence, complemented with intensity at different spectral positions of the Ca II 8542 Å line. The LOS velocities were obtained using Gaussian fitting to the observed Ca II spectra, whereas the POS velocities were derived from a position‑time diagram along a vertical slit in the region of interest (ROI). Complementary to Ca II 8542 Å line scans, EUV intensity images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory were analyzed to investigate the multithermal nature of the observed bidirectional flows. Out of two ROIs, in the first ROI, a large central patch of bidirectional flow was present initially that merged with other patches and disappeared approximately 30 minutes from the beginning, followed by the generation of another set of patches. Cospatial with diverging LOS motions of order 10 km s‑1 associated with patch dynamics, POS motions of similar order were also observed in the ROI. Diverging intensity enhancements in different AIA channels, indicating a multithermal nature of bidirectional flows, were observed cospatially with diverging flows in the POS. Similar dynamics were observed in the second ROI. Bidirectional flow patches and the associated dynamics in LOS and POS may be related to magnetic reconnection inside the prominence.

Keywords: Solar magnetic fields, Stellar spectral lines, Quiescent solar prominence, Solar magnetic reconnection
Implications of Fermionic Dark Matter Interactions on Anisotropic Neutron Stars. The presence of dark matter (DM) within a neutron star (NS) can substantially influence the macroscopic properties. It is commonly assumed that the pressure inside an NS is isotropic, but in reality, pressure is locally anisotropic. This study explores the properties of anisotropic NS with a subfraction of DM (isotropic) trapped inside. Implementing a two-fluid formalism with three distinct classes of equation of state: AP3 (a realistic nucleon─nucleon interaction model), BSk22 (modeling atomic nuclei and neutron matter), and MPA1 (considering relativistic effects in nuclear interactions). The properties of NS, such as mass (M), radius (R), and dimensionless tidal deformability (Λ), for various DM-anisotropic configurations, have been rigorously tested against observational constraints. These constraints include data from the binary NS merger GW170817, NICER X-ray measurements, and pulsar mass─radius observations. We observe that with increasing DM subfraction, higher anisotropies could also satisfy the observational constraints for Yukawa coupling strength g = 10−5, which satisfies the DM self-interaction cross-section (σ) i.e 0.1─10 cm−2 g−1. Furthermore, increasing the coupling (g) between DM and its mediator leads to the formation of a core─halo structure, with a DM halo surrounding the baryonic matter. Specifically, for coupling values of g = 10−4, 10−3.7, and 10−3.5, we observe that the maximum radius (Rmax) decreases with increasing anisotropy, which contrasts with the behavior at g = 10−5 and in scenarios with no DM. Our analysis indicates that binary pulsar systems could potentially constrain the extent of admixed anisotropic NS or, more optimistically, provide evidence for the existence of DM-admixed anisotropic NS.

Keywords: Neutron stars, Dark matter, Compact objects
Investigating the Variable Continuum Lags in PG 2130+099. Broadband photometric reverberation mapping (RM) provides a measure of the size of the continuum-emitting region in active galactic nuclei (AGN). Previous monitoring campaigns of PG 2130+099 disagree as to whether the continuum-emitting region size is consistent with that predicted for a standard optically thick and geometrically thin accretion disk. We present ∼6 months of observations from several robotic telescopes, providing the highest-cadence and widest-wavelength coverage photometric RM study of PG 2130+099 to date. Our results indicate that the inferred size of the continuum-emitting region in PG 2130+099, like many recently observed AGN, is larger than the simplest predictions for an irradiated geometrically thin, optically thick accretion disk. We also perform a flux–flux analysis, finding a variable spectrum broadly consistent with a disk, and a constant component with enhanced i-band emission, potentially due to Hα. We find some evidence of increasing lag with luminosity, but previous lag measurements are too uncertain to be definitive.

Keywords: Supermassive black holes, Reverberation mapping, Active galactic nuclei, Time domain astronomy, Automated telescopes
Properties of Interstellar Medium in the S0 Galaxy NGC 1222: Evidence for Shock-enhanced Line Emission. In this paper, we present a comprehensive study on the properties of the interstellar medium in NGC 1222, a star-forming early-type merging galaxy that forms a triple system, using optical and far-infrared spectroscopic, and multiband photometric data. The fit to the spectral energy distribution reveals a high dust content in the galaxy, with a dust-to-stellar mass ratio of Mdust/M⋆ ∼ 3.3 × 10‑3 that is 40–90 times larger than the mean value of local S0 galaxies. By comparing the observed optical emission line ratios to shock models, we suggest that a merger-induced shock, which is further supported by the higher-than-average [O I] 63 μm- and [C II] 158 μm-to-PAH ratios, plays a role in heating the gas in NGC 1222. We also show evidence for gas inflow by analyzing the kinematic properties of NGC 1222.

Keywords: Early-type galaxies, Interstellar medium, Infrared observatories
Late-time Evolution and Instabilities of Tidal Disruption Disks. Observations of tidal disruption events on timescales of years after the main flare show evidence of continued activity in the form of optical/UV emission, quasiperiodic eruptions, and delayed radio flares. Motivated by this, we explore the time evolution of these disks, using semi-analytic models to follow the changing disk properties and feeding rate to the central black hole. We find that thermal instabilities typically begin ∼100 days after the TDE, causing the disk to cycle between high and low accretion states for up to ∼10 yr. The high state is super-Eddington, which may be associated with outflows that eject ∼10‑3–10‑1 M⊙ over ∼1–2 days, with a range of velocities ∼0.03–0.3c. Collisions between these mass ejections may cause radio flares. In the low state, the accretion rate slowly grows over months to years, as continued fallback accretion builds the disk's mass. In this phase, the disk has a luminosity of ∼1041–1042 erg s‑1 in the optical/UV, as seen in some late-time observations. Although the accretion cycles we find occur for a typical α-disk, in nature, the disk could be stabilized by other effects, such as the disk's magnetic field or heating from fallback accretion, the latter of which we explore. Thus, higher-cadence optical/UV observations along with joint radio monitoring will be key for following the disk state and testing these models.

Keywords: Accretion, Supermassive black holes, Tidal disruption, Transient sources
Gravity-selected Cluster Samples: A New Take on the Compton-y–Mass Relation. We investigate the scaling relation between the Compton-y parameter and mass in a gravity-selected sample of galaxy clusters, selected based on their gravitational lensing effects on background galaxies. Unlike intracluster medium (ICM)‑selected samples, gravity-selected clusters do not require corrections for selection biases in ICM properties, such as Compton-y, since these properties are not used for selection. Our sample consists of 13 gravity-selected clusters with weak-lensing signal-to-noise ratios greater than 7 and redshifts in the range 0.1 &lt; z &lt; 0.4, drawn from the peak catalog of shear-selected clusters in M. Oguri et al. We determined spectroscopic redshifts using Sloan Digital Sky Survey spectroscopy, derived tangential radial profiles from Hyper Suprime-Cam shear data, and calculated cluster masses by fitting a Navarro, Frenk, &amp; White profile. Compton-y measurements were obtained from Atacama Cosmology Telescope maps. Our sample reveals a broader scatter in the Compton-y–mass scaling relation compared to ICM-selected samples, even after accounting for selection effects and mass bias of the latter, which we find to be (1 ‑ b) = 0.72 ± 0.09. Additionally, we identify a second population of clusters with unusually small Compton-y for their mass, which is absent in ICM-selected samples. This second population composes  % of the entire sample, with O19 currently being the only secure representative.

Keywords: Galaxy clusters, Intracluster medium, Sky surveys
Recovering Pulsar Braking Index from a Population of Millisecond Pulsars. The braking index, n, of a pulsar is a measure of its angular momentum loss and the value it takes to correspond to different spin-down mechanisms. For a pulsar spinning down due to gravitational-wave emission from the principal mass quadrupole mode alone, the braking index would equal exactly 5. Unfortunately, for millisecond pulsars, it can be hard to measure observationally due to the extremely small second time derivative of the rotation frequency,  . This paper aims to examine whether it could be possible to extract the distribution of n for a whole population of pulsars rather than measuring the values individually. We use simulated data with an injected n = 5 signal for 47 ms pulsars and extract the distribution using hierarchical Bayesian inference methods. We find that while possible, observation times of over 20 yr and rms noise of the order of 10‑5 ms are needed, which can be compared to the mean noise value of 3 × 10‑4 ms for the recent wide-band 12.5 yr NANOGrav sample, which provided the pulsar timing data used in this paper.

Keywords: Neutron stars, Millisecond pulsars, Gravitational wave sources, Pulsars, Gravitational waves, Compact objects, Stellar remnants
The BoRG-JWST Survey: Abundance and Mass-to-light Ratio of Luminous z = 7─9 Galaxies from Independent Sight Lines with NIRSpec. We present new results on the rest-frame UV luminosity function (UVLF) and stellar mass-to-light (M/L) ratio of bright (MUV ≲ −20 mag) spectroscopically confirmed galaxies at z = 7─9 derived from the BoRG-JWST survey, a unique data set of NIRSpec prism follow-up of Hubble Space Telescope (HST)─selected sources from random-pointing imaging. By selecting galaxies from over 300 independent sight lines, the survey minimizes cosmic variance, ensuring a statistically robust sample of the bright-galaxy population during the epoch of reionization. The data are used to constrain, for the first time, the bright end of the UVLF at z = 7─9 from spectroscopically confirmed galaxies over eight independent fields. We find that the bright end of the UVLF is higher than found using imaging over JWST legacy fields, suggesting that the latter may be significantly affected by cosmic variance, and thus reducing the tension with recent findings from JWST at z &gt; 10 and comparable to models invoking little dust attenuation and bursty star formation. Additionally, we use the galaxies' JWST spectra to infer their stellar masses and M/L ratios relative to other HST and JWST studies. We show that the stellar mass scales almost linearly with UV luminosity (M ), albeit with large (∼0.5 dex) intrinsic scatter, consistent with stochastic bursts of star formation in early galaxy formation.

Keywords: Cosmology, Observational astronomy, Star formation, Reionization, High-redshift galaxies
Virgo Filaments. V. Disrupting the Baryon Cycle in the NGC 5364 Galaxy Group. The Virgo Filament Survey (VFS) is a comprehensive study of galaxies that reside in the extended filamentary structures surrounding the Virgo Cluster, out to 12 virial radii. The primary goal is to characterize all of the dominant baryonic components within galaxies and to understand whether and how they are affected by the filament environment. A key constituent of VFS is a narrowband Hα imaging survey of over 600 galaxies, VFS-Hα. The Hα images reveal detailed, resolved maps of the ionized gas and massive star formation. This imaging is particularly powerful as a probe of environmentally induced quenching because different physical processes affect the spatial distribution of star formation in different ways. In this paper, we present the first results from the VFS-Hα for the NGC 5364 group, a low-mass ( ) system located at the western edge of the Virgo III filament. We combine Hα imaging with resolved H I observations from MeerKAT for eight group members. These galaxies exhibit peculiar morphologies, including strong distortions in the stars and the gas, truncated H I and Hα disks, H I tails, extraplanar Hα emission, and off-center Hα emission. These signatures are suggestive of environmental processing such as tidal interactions, ram pressure stripping, and starvation. We quantify the role of ram pressure stripping expected in this group, and find that it can explain the cases of H I tails and truncated Hα for all but one of the disk-dominated galaxies. Our observations indicate that multiple physical mechanisms are disrupting the baryon cycle in these group galaxies.

Keywords: Large-scale structure of the universe, Galaxy environments, Cosmic web, Galaxy groups, Galaxy quenching