Sazuna/UAT_keywords huggingface dataset:
A Drag-force Analysis of Solar Wind White-light Tracers in the Inner Heliosphere. We studied the propagation of blobs, which are a subset of density mesoscale structures observed in the solar corona. The detection of blobs in white-light data was performed during Solar Cycle 23. Blobs are tracers of the solar wind and an important source of its variability. We analyzed the deprojected blob radial elongation and kinematics as they evolved in the inner heliosphere using a dynamical "drag-force" model. We characterized 13 blob-like structures detected by Large Angle Spectrometric Coronagraph and SECCHI coronagraphs aboard Solar and Heliospheric Observatory and Solar TErrestrial RElations Observatory, respectively. We applied, for the first time, analysis techniques that were typically used for coronal mass ejections to these compact plasma blobs that seem to propagate "passively" with the solar wind. This is the first time that the mass of blobs has been reported, with a mean value of 3.32 ± 0.19 × 1012 g. In addition, blobs show a mean radial expansion rate of 1.10 ± 0.96 × 10−1 R⊙ hr−1. We assumed that the blob movement is governed by a force that is active at a heliocentric distance ∼5 R⊙, "dragging" blobs near the Sun outward until they reached a mean final velocity of 427 ± 55 km s−1 at ∼15 R⊙. According to the physical parameters involved in this "drag-force" model, the best estimate of the dynamic viscosity of the ambient solar wind is 1.27 ± 0.98 × 10−4 g cm−1 s−1. This is also the first time that this crucial parameter for aerodynamical studies has been reported close to the Sun.

Keywords: Space plasmas, Solar coronal transients, Solar K corona, Hydrodynamics, Solar wind, Solar physics, Solar coronal streamers
The Response of Planetary Atmospheres to the Impact of Icy Comets. II. Exo-Earth Analogs. The orbital regime of a terrestrial planet plays a significant role in shaping its atmospheric dynamics, climate, and hence potential habitability. The orbit is also likely to play a role in shaping the response of a planetary atmosphere to the influx of material from an icy cometary impact. To investigate this response, we model the impact of an icy cometary body with an Earth-analog exoplanet (i.e., an Earth-like planet orbiting a Sun-like star with a diurnal cycle) using a cometary impact and breakup model coupled with the 3D Earth system model WACCM6/CESM2. To quantify the role that the atmospheric dynamics play in setting the response to a cometary impact, we compare our results with a previous study investigating an impact with a tidally locked terrestrial exoplanet. We find that the circulation regime of the planet plays a key role in shaping the response of the atmosphere to an icy cometary impact. The weak multicelled circulation structure that forms on Earth-like planets is efficient at mixing material horizontally but not vertically, limiting the transport of water from the deep breakup site to higher altitudes. In turn, this limits the rate of water photodissociation at low pressures, reducing the magnitude of postimpact changes to composition. It also reduces the potential observability of an impact due to weakened cloud ice formation, and hence scattering, at low pressures. Despite this, small changes to the overall composition of the planet persist to a quasi steady state, reinforcing the idea that ongoing bombardment may help to shape the composition/habitability of terrestrial worlds.

Keywords: Exoplanet atmospheric composition , Exoplanet atmospheric dynamics, Planetary atmospheres, Computational methods, Atmospheric composition, Atmospheric dynamics, Exoplanet atmospheres
Invisible Accretion: Ionized Envelopes of TNG50 HVCs Can Sustain Star Formation. Galactic high-velocity clouds (HVCs) are known to be complex, multiphase systems consisting of neutral and/or ionized gas moving at high velocities relative to the rotation of the disk. In this work, we investigate Milky Way–like galaxies from the TNG50 simulation to characterize the properties, morphology, and accretion rates of the warm and hot ionized material comoving with neutral HVCs visible in H I. We find that the ionized gas forms an envelope around the neutral material, and in most cases (73% of the HVCs), it is prolate in morphology. We also find that the ionized mass is ∼6 times greater than the neutral mass, which leads to significantly more accretion being possible from the ionized gas ( Ṁion ) than the neutral gas ( Ṁneut ), consistent with estimates made from observations of our own Galaxy. We investigate the accretion rates from both phases of HVCs around 47 Milky Way–like galaxies, finding that  Ṁion  scales with  Ṁneut  and both scale with the star formation rate of the galaxy. Finally, we find that, on average,  Ṁion  could account for 81% of the galactic star formation rate (assuming the material can sufficiently cool and condense), while  Ṁneut  can only balance 11%. Thus, the diffuse, ionized, high-velocity circumgalactic medium plays a defining role in the evolution and growth of galaxies at low redshift.

Keywords: High-velocity clouds, Milky Way Galaxy, Astronomical simulations, Circumgalactic medium
GrAviPaSt's Lens to the Past: Unveiling the Evolution of Filamentary Structures. This paper examines the evolution of cosmic filaments across redshifts 1, 0.5, and 0 using the IllustrisTNG100-1 magnetohydrodynamical simulation. To achieve this, we introduce GrAviPaSt, a simple, efficient, and parameter-free filament identification method that leverages gravitational potential, an A*-like pathfinding algorithm, and spanning trees. Applying this method to galaxy distributions at different redshifts allows us to analyze various filament properties, including their length, thickness, mass density contrast, and radial profile. Additionally, we investigate dynamic characteristics such as the mean distance of filament galaxies from the skeleton, their weighted mean velocity, and velocity trends normalized by their positions within the filaments. Our findings reveal the evolution of cosmic filaments from redshift 1–0, highlighting key differences across classifications. In particular, we examine the mass density contrast radial profile of filaments connecting two galaxy groups and those linking two galaxy clusters, identifying distinct differences in profile shape between these categories. Furthermore, in the context of weighted mean velocity, we analyze cosmic filaments exhibiting either negative or positive weighted mean velocity, demonstrating their differing evolutionary trends in terms of the mean distance of filament galaxies from the skeleton.

Keywords: Galaxy environments, Computational methods, Cosmic web, Large-scale structure of the universe
The Astrid Simulation: Evolution of Black Holes and Galaxies to z = 0.5 and Different Evolution Pathways for Galaxy Quenching. We present new results from the ASTRID simulation from z = 3 to z = 0.5, covering the epoch of cosmic noon. The galaxy stellar mass function, as well as the black hole mass and luminosity functions in ASTRID, exhibit good agreement with recent observational constraints. We study the MBH─M*scaling relation and its connections to active galactic nucleus (AGN) luminosity, galaxy color, and star formation rate, demonstrating that AGN feedback plays a crucial role in the quenching of massive galaxies (M* &gt; 1010.5 M⊙). Although AGN feedback ultimately suppresses star formation through quenching, AGN-host galaxies can still exhibit statistically higher star formation rates than inactive ones, reflecting a positive correlation driven by their shared dependence on a common cold gas reservoir. The fraction of quiescent galaxies in ASTRID increases with both galaxy mass and redshift evolution, aligning well with observational trends. We find that different quenching mechanisms can leave distinct morphological imprints on quenched galaxies. Massive, compact quiescent galaxies typically experience shorter quenching timescales, have younger central regions, and host overmassive black holes. This is usually due to a compaction-like quenching mechanism that funnels gas into the galactic center, leading to starbursts and triggering AGN kinetic feedback. In contrast, quiescent galaxies with more diffuse morphologies generally experience "inside-out" quenching, which is characterized by older central regions compared to the outskirts. These galaxies typically experience longer quenching timescales due to quenching processes operating on a larger halo scale, which gradually deplete the galactic star-forming gas. Data of the ASTRID simulation down to z = 0.5 is available at https://astrid.psc.edu.

Keywords: AGN host galaxies, Hydrodynamical simulations, Supermassive black holes
Tracing Magnetic Signatures through the Solar Atmosphere in Seven Eruptive Active Regions. This case study focuses on the pre-eruptive conditions of active regions that produced either low-energy flares accompanied by major CMEs (AR 12371 and AR 11692) or major X-class flares also associated with significant CMEs (AR 12673, AR 12158, AR 11520, AR 11429, and AR 13664). The study examines the evolution of 10 morphological parameters that serve as indicators of pre-eruptive conditions—not only at the photosphere but also in higher layers of the solar atmosphere. We found that active regions with a greater number of parameters exceeding their threshold values at higher altitudes tend to exhibit a higher eruptive potential. Specifically, in active regions associated with X-class flares and fast CMEs, at least 8 out of 10 parameters exceeded their thresholds at elevated layers, whereas in the 2 active regions linked to M-class flares and fast CMEs, fewer than 7 parameters did so. These results suggest that assessing the height-dependent behavior of pre-eruptive proxy parameters could significantly improve the identification and prediction of eruptive active regions. Future studies should extend this approach to a larger data set to better determine the maximum atmospheric height at which the predictive thresholds of different parameters are met, thereby enhancing the accuracy of solar eruption prediction.

Keywords: Solar flares
Application of Physics-informed Neural Networks in Removing Telescope Beam Effects. This study introduces PI-AstroDeconv, a physics-informed semi-supervised learning method specifically designed for removing beam effects in astronomical telescope observation systems. The method utilizes an encoder–decoder network architecture and combines the telescope's point-spread function or beam as prior information, while integrating Fast Fourier Transform–accelerated convolution techniques into the deep learning network. This enables the effective removal of beam effects from astronomical observation images. PI-AstroDeconv can handle multiple point-spread functions or beams, tolerate imprecise measurements to some extent, and significantly improve the efficiency and accuracy of image deconvolution. Therefore, this architecture is particularly suitable for astronomical data processing that does not rely on annotated data. To validate the reliability of the architecture, we used the Square Kilometre Array Science Data Challenge 3a data sets and compared it with the CLEAN deconvolution method at the 21 cm power spectrum level. The results demonstrate that our algorithm not only restores details and reduces blurriness in celestial images at the pixel level, but also more accurately recovers the true neutral hydrogen power spectrum at the power spectrum level.

Keywords: Observational cosmology, Convolutional neural networks, Radio telescopes, H I line emission
Early-type Galaxies on the Star Formation Main Sequence: Internal Star Formation Geometries Revealed with MaNGA and Their Environmental Origin. Star-forming galaxies on the main sequence (MS) are often regarded as a uniform population characterized by similar global star formation properties. However, there exists a diversity in galaxy morphologies at a fixed stellar mass and star formation rate. In this study, using spatially resolved properties from the MaNGA final data release, we classify MS galaxies into late type (MS-late) and early type (MS-early). In addition, we further divide the MS-early galaxies into two distinct subgroups based on their internal star formation and stellar mass distributions within the galaxies. The first group—"MS-early_SF"—shows centrally concentrated star formation without prominent stellar bulges and resides preferentially in dense environments, suggesting environmentally driven evolution. The second group—"MS-early_stellar"—exhibits significant stellar bulges with suppressed central star formation, maintains disk-like star formation patterns, and inhabits environments similar to those of late-type galaxies, indicating evolution through internal secular processes. Our findings demonstrate that spatially resolved observations play critical roles in revealing the diverse evolutionary pathways hidden within galaxies that share similar global properties.

Keywords: Late-type galaxies, Early-type galaxies, Galaxy environments
Tidal Synchronization of TESS Eclipsing Binaries. Tidal synchronization plays a fundamental role in the evolution of binary star systems. However, key details such as the timescale of synchronization, efficiency of tidal dissipation, rotation period, and dependence on stellar mass are not well constrained. We present a catalog of rotation periods, orbital periods, and eccentricities from eclipsing binaries (EBs) that can be used to study the role of tides in the rotational evolution of low-mass dwarf (FGKM spectral type) binaries. This study presents the largest catalog of EB orbital and rotational periods (Porb and Prot) measured from the Transiting Exoplanet Satellite Survey (TESS). We first classify 4584 light curves from the TESS EB catalog according to out-of-eclipse stellar variability type: starspot modulation, ellipsoidal variability, nonperiodic variability, and "other" variability (e.g., pulsations). We then manually validate each light curve's classification, resulting in a sample of 1039 candidates with 584 high-confidence EBs that exhibit detectable starspot modulation. From there, we measure and compare the rotation period of each starspot-modulated EB using three methods: a Lomb─Scargle periodogram, autocorrelation function, and phase dispersion minimization. We find that our period distributions are consistent with previous work that used a sample of 816 starspot EBs from Kepler to identify two populations: a synchronous population (with Porb ≍ Prot), and a subsynchronous population (with 8Porb ≍ 7Prot). Using Bayesian model comparison, we find that a bimodal distribution is a significantly better fit than a unimodal distribution for the Kepler and TESS samples, both individually or combined, confirming that the subsynchronous population is statistically significant.

Keywords: Starspots, Late-type stars, Close binary stars, Eclipsing binary stars, Stellar rotation
The R-process Alliance: Enrichment of r-process Elements in a Simulated Milky Way─like Galaxy. We study the formation of stars with varying amounts of heavy elements synthesized by the rapid neutron-capture process (r-process) based on our detailed cosmological zoom-in simulation of a Milky Way─like galaxy with an N-body/smoothed particle hydrodynamics code, ASURA. Most stars with no overabundance in r-process elements, as well as the strongly r-process-enhanced (RPE) r-II stars ([Eu/Fe] &gt; +0.7), are formed in dwarf galaxies accreted by the Milky Way within the 6 Gyr after the Big Bang. In contrast, over half of the moderately enhanced r-I stars (+0.3 &lt; [Eu/Fe] ≤ +0.7) are formed in the main in situ disk after 6 Gyr. Our results suggest that the fraction of r-I and r-II stars formed in disrupted dwarf galaxies is larger the higher their [Eu/Fe] is. Accordingly, the most strongly enhanced r-III stars ([Eu/Fe] &gt; +2.0) are formed in accreted components. These results suggest that non-r-process-enhanced stars and r-II stars are mainly formed in low-mass dwarf galaxies that hosted either none or a single neutron star merger, while the r-I stars tend to form in the well-mixed in situ disk. We compare our findings with high-resolution spectroscopic observations of RPE metal-poor stars in the halo and dwarf galaxies, including those collected by the R-Process Alliance. We conclude that observed [Eu/Fe] and [Eu/Mg] ratios can be employed in chemical tagging of the Milky Way's accretion history.

Keywords: Chemical enrichment, Galactic archaeology, Milky Way Galaxy, R-process
The Shape of AGN-driven Winds in the Seyfert Galaxy NGC 3516. Active galactic nuclei (AGN) are known to drive ionized gas into their host galaxies, which may affect the evolution of both the central supermassive black holes and their hosts. In the case of NGC 3516, a nearby Seyfert 1 galaxy, these AGN winds have historically proven difficult to disentangle from galactic rotation. Using long-slit spectroscopy at multiple position angles from Hubble Space Telescope's Space Telescope Imaging Spectrograph and Apache Point Observatory's Kitt Peak Ohio State Multi-Object Spectrograph, we separate these kinematic components by fitting multiple Gaussians to the Hα, [N II], Hβ, and [O III] emission lines along the slits. We present a biconical outflow model that agrees well with the observed kinematics of the outflowing gas in the narrow-line region (NLR). Our results indicate that the structure of the [O III] emission is explained by dusty gas spirals in the galactic disk that are illuminated by the ionizing bicone, which is viewed along one edge, resulting in the complex nuclear kinematics. Our view into the bicone edge is consistent with the multiple, deep components of ionized absorption lines seen in UV and X-ray spectra of NGC 3516. The observed turnover in the velocity of the NLR clouds matches that from a simple dynamical model of radiative acceleration by the AGN and gravitational deceleration by the AGN and galaxy, indicating they are the principal forces at work on the gas clouds. Finally, the model launch radii indicate that the outflowing clouds originate primarily from the inner dusty spirals near the AGN.

Keywords: AGN host galaxies, Supermassive black holes, Emission line galaxies, Low-luminosity active galactic nuclei, Seyfert galaxies, Galaxy winds, Galaxy kinematics
The Outskirt Stellar Mass of Low-redshift Massive Galaxies Is an Excellent Halo Mass Proxy in Illustris/IllustrisTNG Simulations. Recent observations suggest that the extended stellar halos of low-redshift massive galaxies are tightly connected to the assembly of their dark matter halos. In this paper, we use the Illustris, IllustrisTNG100, and IllustrisTNG300 simulations to compare how different stellar aperture masses trace halo mass. For massive central galaxies (M⋆ ≥ 1011.2 M⊙), we find that a 2D outskirt stellar mass measured between 50 and 100 kpc (M⋆,[50,100]) consistently outperforms other aperture-based stellar masses. We further show that M⋆,[50,100] correlates better with halo mass than the total mass of accreted stars (the ex situ mass), which suggests that not all accreted stars connect to halo assembly equally. While the galaxy formation recipes differ between Illustris and IllustrisTNG100, the two simulations yield consistent ex situ outskirt fractions for massive galaxies (∼70% in M⋆,[50,100]). These results demonstrate the potential of using the outskirt stellar mass to deepen our understanding of the galaxy–halo connection in massive dark matter halos and to trace dark matter halos better.

Keywords: Galaxy dark matter halos, Galaxy formation, Hydrodynamical simulations, Galaxy physics, Galaxy structure, Galaxy stellar halos
The Parallel Diffusion Coefficient of Energetic Particles in a Spatially Varying Magnetic Field. In the theory of energetic particle transport, the spatial variation of large-scale magnetic fields gives rise to a so-called adiabatic focusing term in the pitch-angle-dependent transport equation. This focusing term leads to the effect of convection, but it also alters the parallel spatial diffusion coefficient. Over the past few decades researchers have tried to derive analytical forms for the parallel diffusion coefficient as a function of the focusing length. Two different results have been derived contradicting each other. In the current paper we revisit this problem and provide the final solution. We combine previously developed numerical methods such as the subspace approach, allowing us to compute the parallel diffusion coefficient as a function of the focusing length with very high precision within a very short computational time. Most importantly, we derive an exact formula for the diffusion coefficient by employing analytical theory. The new formula agrees perfectly with the numerically obtained results proofing its validity.

Keywords: Solar energetic particles, Galactic cosmic rays
Effect of Positronium on the γ-Ray Spectra and Energy Deposition in Type Ia Supernovae. Type Ia supernovae (SNe Ia) are powered by the radioactive decay of isotopes such as 56Ni and 56Co, making their γ-ray spectra useful probes of the explosion mechanism and ejecta structure. Accurate interpretation of γ-ray observables, including line ratios and continuum fluxes, requires a detailed understanding of the microphysical processes that shape the spectra. One such process is positronium formation during electron–positron annihilation, which can redistribute flux from the 511 keV line into the surrounding continuum. To assess the impact of positronium on the emergent spectra, we developed a new open-source module, TARDIS-HE, for time-dependent three-dimensional γ-ray transport, integrated into the radiative transfer code TARDIS. The code simulates γ-ray spectra and light curves from one-dimensional supernova ejecta models and allows for flexible incorporation of decay chains and opacity treatments. Using TARDIS-HE, we explore the effect of positronium formation by varying the positronium fraction from 0% to 100%, and assuming an extreme case where 75% of positronium decays result in three-photon emission. We find that full positronium formation can reduce the 511 keV line flux by ≈70% and modestly enhance energy deposition by up to 2% at around 100 days postexplosion, compared to models without positronium. These results demonstrate that, while the effect is not dominant, positronium formation introduces measurable changes to γ-ray observables. Future observations with missions such as the Compton Spectrometer and Imager may offer constraints on positronium formation in SNe Ia and help refine models of their radioactive energy transport.

Keywords: Gamma-ray transient sources, Supernovae, Nucleosynthesis, Gamma-rays