Sazuna/UAT_keywords huggingface dataset:
Galaxies Caught in Transition: The Role of Group Environment in Shaping the Mass─Size Relation in the Local Universe. The stellar mass─size relation is a sensitive probe of how environment shapes galaxy structure. We analyse this relation in the local Universe for galaxies in compact groups (CGs), low-mass groups (Mvir ≤ 1013 M⊙), and high-mass groups, comparing them to field galaxies using data from the Southern Photometric Local Universe Survey. Galaxies are classified as early-type galaxies (ETGs; n ≥ 2.5, (u − r)0 ≥ 2.2), late-type galaxies (LTGs; n &lt; 2.5, (u − r)0 &lt;2.2), transition galaxies (TGs; n &lt; 2.5, (u − r)0 ≥ 2.2), and other galaxies (OGs; n ≥ 2.5, (u − r)0 &lt;2.2). We find that ETGs and OGs show no significant environmental dependence: their mass─size slopes and intercepts are statistically consistent across CGs, groups, and the field. LTGs also follow similar relations in the field and in most groups, with only a modest tendency for LTGs in CGs to be smaller at fixed stellar mass. By contrast, TGs display a clear environmental signal: in groups the slope steepens to α ∼ 0.4 (versus α ∼ 0.2 in the field) and their sizes are smaller than in the field, with nonoverlapping 95% posterior intervals. These trends suggest that TGs in denser environments are more structurally evolved, likely owing to enhanced bulge prominence and fading of the outer disk, consistent with the Sérsic-index distributions, which show an excess of TGs with nr ≳ 1.5 in groups and CGs. Our findings highlight TGs as an environmentally sensitive population, providing insight into the structural transformation of galaxies in group environments.

Keywords: Galaxy evolution, Galaxy interactions, Galaxy groups, Galaxy environments
Tilt Angles of Sunspot Groups in Different Latitude Bands and the Amplitude of the Next Solar Cycle. In the Babcock─Leighton and Parker dynamo models, the tilt angle of a sunspot group (SG) and the turbulence in the solar convection zone (one widely accepted generation mechanism responsible for the scatter of the tilt angles of SGs around the mean), respectively, are thought to represent the source of the poloidal field, which serves as the seed field for the toroidal field forming SGs during the next solar cycle (SC). We analyse the sunspot data from the Kodaikanal observatory to investigate the relationships of the mean tilt angles and the tilt-angle scatters (the standard deviations of the tilt angles) in different latitude bands with the amplitude of the next/same SC. The two main findings of our analysis are as follows. (1) The mean tilt angle at low latitudes (≤10∘) has a significant positive correlation with the amplitude of the next SC; however, the mean tilt angle at high latitudes (&gt;20∘) shows a significant anticorrelation with the amplitude of the next SC. (2) The tilt-angle scatter at low latitudes exhibits a significant anticorrelation with the amplitude of the next SC, while the tilt-angle scatter at high latitudes has a significant positive correlation with the amplitude of the same SC. These findings suggest that the tilt angles of SGs in different latitude bands play different roles in regulating SC variability.

Keywords: Solar cycle, Sunspot groups, Solar dynamo
The Progenitor of the S147 Supernova Remnant. The supernova remnant (SNR) S147 contains the pulsar PSR J0538+2817 and a likely unbound binary companion, HD 37424. It is the only good Galactic candidate for a binary unbound by a core-collapse supernova. Using Gaia DR3 parallaxes and photometry, we select the stars local to SNR S147 ( ϖS147=0.73−0.05+0.04mas ) in a cylinder with a projected radius of 100 pc and a parallax range of 0.614 &lt; ϖ &lt; 0.787 mas (a length of ≃360 pc). We individually model the most luminous of these stars. The two most luminous single stars are the unbound binary companion, HD 37424, and HD 37367, with estimated masses of (13.51 ± 0.05) M⊙ and (14.30 ± 0.09) M⊙, respectively. The two most luminous binary systems are the spectroscopic binary HD 37366 and the eclipsing binary ET Tau, which have primary masses of (20.9 ± 0.12) and (16.7 ± 0.09) M⊙, respectively. We model the Gaia color─magnitude diagram of this local stellar population using both single stars and a model consisting of noninteracting binaries using solar metallicity PARSEC v2.0 isochrones. For both models, the estimated age distributions of the 439 MG &lt; 0 mag stars favor a high-mass progenitor of 21.5─41.1 M⊙ for the supernova.

Keywords: Supernovae, Core-collapse supernovae
Improving the Shock Propagation Model of SPM3 by Incorporating the Solar Energetic Particle Flux and the Principal Component Analysis Method. Coronal mass ejections (CMEs), as one of the most destructive solar activity phenomena, are the primary driver of extreme space weather events. Accurately predicting the probability and arrival time of the corresponding interplanetary CMEs and their associated shocks is crucial in space weather forecasting. Currently, the primary shock propagation prediction models mainly input the initial kinematic parameters of CMEs near the Sun. The physics-based Shock Propagation Model Version 3 (SPM3) has demonstrated a good forecasting performance for the CME/shock events from 2013 January to 2023 July. To further improve the prediction accuracy, this study incorporates the flux of solar energetic particles (SEPs). A composite index (I), constructed using principal component analysis, quantifies the combined influence of SEP and CME's source longitude. The analysis reveals that SPM3 systematically underestimates the shock's transit times when the I &lt; 0.2 and VCME &lt; 650 km s−1. For the events identified by these criteria, an empirical velocity-based bias correction is applied. Notably, the SEP flux data are specifically used to flag events where the correction is applied, rather than entering as a continuous predictor. The revised version SPM3v2 achieves a total prediction success rate of 61%, with mean absolute error and root mean square error reduced to 8.27 and 10.65 hr, outperforming the original SPM3.

Keywords: Interplanetary shocks, Solar energetic particles, Space weather, Solar coronal mass ejections, Solar-terrestrial interactions
Early Results from the Coma Legacy IFU Survey (CLIFS): Ram Pressure Induced Shocks and Ionization in Jellyfish Tails. Jellyfish galaxies, which exhibit tails of gas opposite to their direction of motion, are a galaxy population showcasing the most extreme effects of ram pressure stripping (RPS). We present the emission line properties of a preliminary sample of five jellyfish galaxies in the Coma cluster, observed with the WEAVE Large-IFU as part of the Coma Legacy IFU Survey (CLIFS). When complete, CLIFS will form a sample of 29 jellyfish galaxies in Coma, selected based on the presence of one-sided tails in the radio continuum, enabling a comprehensive picture of the effects of ram pressure on galaxies in the Coma cluster. We extract emission line properties and confirm consistency between disk fluxes measured from WEAVE and MaNGA for galaxies with overlapping disk coverage between surveys. Comparing resolved radio and Hα-based star formation rates, we find that, in contrast to the disk, the dominant source of tail emission is not star formation. We find evidence for diffuse ionized gas excited by RPS-driven shocks in the tails, as indicated by: (1) LINER-like tail emission with the [O I]/Hα Baldwin-Phillips-Terlevich diagnostic; (2) enhanced [O II]/Hα ratios in the tails relative to the disks; and (3) similarly elevated emission line velocities and velocity dispersions in the tails with respect to the disks. These results demonstrate that ram pressure driven shocks dominate the ionized emission in jellyfish galaxy tails.

Keywords: Galaxy clusters, Galaxy environments, Galaxy infall, Galaxy evolution, Galaxies
Statistical Patterns in the Time Evolution of Interface Region Imaging Spectrograph Bright Points. Interface Region Imaging Spectrograph bright points (IBPs) are ubiquitous, small-scale energetic events with a multithermal nature, typically observed in the chromosphere or transition region and closely linked to photospheric structure and coronal composition. Their evolution is shaped by various physical processes, including plasma dynamics and magnetic interactions. This paper explores IBP evolution through a large statistical sample, focusing on when maximum values of attributes occur, and examines whether statistical differences exist between "Active Quiet Sun" (AQS; above the network) and "True Quiet Sun" (TQS; above the internetwork) IBPs. The attributes analyzed are maximum brightness, plane-of-sky (POS) speed, POS travel distance, POS acceleration, and apparent size (POS area). IBPs can reach peak brightness/size at any point during their lifetimes, likely due to complex chromospheric interactions. AQS and TQS IBPs are similar in most attributes and tend to reach maximum POS speed around halfway through their lifetimes. Acceleration typically occurs early in their lifetime, with deceleration more common toward the end. Preliminary findings indicate two distinct IBP regimes with differing relationships between POS speed, brightness, and area. This study provides strong statistical evidence that IBPs—whether representing plasma motion or propagating heating events—follow arched trajectories along small magnetic loops. In this interpretation, the midpoint of an IBP's lifetime corresponds to the crest of the arch, coinciding with the highest POS travel speeds. Magnetic reconnection likely initiates at photospheric footpoints, after which IBPs travel along loops, eventually returning to another footpoint. Deviations from loop-like evolution reflect complexity, asymmetry, and variability of loops.

Keywords: Solar magnetic reconnection, Quiet solar chromosphere, Quiet sun, Solar magnetic fields, Solar magnetic bright points
Spectroscopy and Photochemistry of the Astrochemical Molecules SiCP and AlCP. Through characterization of the electronic excited-state topology, linear-SiCP is predicted to be photostable in the UV region, whereas linear-AlCP is predicted to undergo photodissociation to form Al+CP products after absorption of light in the 200─250 nm range, representing a catalytic process for freeing aluminum molecules from a solid dust grain. Both SiCP and AlCP are predicted to have electronic transitions with large absorption cross sections (∼10─17 cm2) and to undergo fluorescence from bound excited states. The total electronic absorption spectrum is provided to inform electronic spectroscopy experiments. Silicon (SiC) and aluminum (Al2O3) dust grains are ubiquitous in the interstellar medium, and are especially prominent in the circumstellar envelopes of evolved stars such as VY CMa and IRC+10216. These regions of space are hotbeds for chemical activity, where reactions can occur on the surfaces of these dust grains to form new species. One such reaction that has been theorized involves the CP radical interacting with dust grain surfaces to produce the triatomic molecules SiCP and AlCP. To motivate and facilitate experimental and observational searches for AlCP, its ground-state spectroscopic properties (rotational and vibrational) have been investigated. The small permanent dipole moment (∼0.1 D) is expected to make radioastronomical observation difficult, although experimental detection may be feasible if a sufficiently large molecular number density can be achieved.

Keywords: Computational methods, Molecular spectroscopy, Astrochemistry
Searching for White Dwarf Candidates Formed Through Binary Evolution in Star Clusters. White dwarfs (WDs), the evolutionary endpoints of most stars, can form through both single-star and binary channels. While single-star evolutionary models enable reliable WD age estimates, binary evolution introduces interactions that can accelerate WD formation and result in a variety of exotic WDs, which may exhibit strong magnetic fields, rapid rotation, or even serve as potential gravitational wave sources. Such systems offer valuable insights into magnetic field generation, angular momentum evolution, and compact object physics. Star clusters, with their approximately coeval populations, allow precise age determination of member WDs. If a WD's total age derived from single-star evolution exceeds that of its host cluster, it likely indicates a binary origin. In this study, we use Gaia 5D astrometry to identify 439 WD candidates in 117 open clusters, with 244 likely formed via binary evolution. We discuss the possibility of dynamical ejection for WDs meeting only 2D (proper motion space) membership criteria. Spectroscopic observations further reveal a subset with strong magnetic fields and rapid rotation, supporting their binary evolutionary origin.

Keywords: Close binary stars, Open star clusters, White dwarf stars
Search for Ultra-high-energy Neutrons from Galactic Sources with the Pierre Auger Observatory. Deflections in the propagation of charged ultra-high-energy cosmic rays (UHECRs) caused by magnetic fields make the identification of their sources challenging. On the other hand, the arrival directions at Earth of neutrons point directly to their origin. The emission of UHECRs from a source is expected to be accompanied by the production of neutrons in its vicinity through interactions with ambient matter and radiation. Since free neutrons travel a mean distance d kpc−1 = 9.2 (E EeV−1) before decaying, a neutron flux in the EeV range could be detected on Earth from sources of UHECRs in our Galaxy. Using cosmic-ray data from Phase I of the Surface Detector of the Pierre Auger Observatory, we search for neutron fluxes from Galactic candidate sources. We select more than 1000 objects of astrophysical interest, stacking them into target sets. The targets all have decl. within the exposure of the Observatory, ranging from −90° up to +45° for energies above 1 EeV (and up to +20° for energies down to 0.1 EeV). Given that a neutron air shower is indistinguishable from a proton one, there is a significant background due to cosmic rays. A neutron flux from the direction of a candidate source would be identified by a celestial density of events that significantly exceeds the expected density of cosmic rays for that direction. No significant excess is found at any tested target direction, and an upper limit on the neutron flux is calculated for each candidate source.

Keywords: Galactic cosmic rays, High energy astrophysics, Ultra-high-energy cosmic radiation, Cosmic rays
Transverse Oscillations and Wave Propagation in the Magnetically Dominated M87 Jet. We present an in-depth analysis of the transverse oscillations in the M87 jet, as identified in our previous study, which reported oscillatory patterns with a characteristic period of ∼1 yr in the edge-brightened jet structure extending up to 12 mas from the core. This work is based on high-cadence KaVA 22 GHz observations conducted from 2013 December to 2016 June. By analyzing the transverse velocity profiles and the spatial evolution of the oscillations, we find that the oscillations propagate downstream along the jet, with a wavelength of ∼9─10 mas. A single-mode sinusoidal wave model applied to the ridgelines successfully reproduces the observed transverse oscillations and yields superluminal wave speeds of ∼2.7─2.9c, consistent with the bulk jet velocity in this region. These findings suggest that the transverse oscillations may be interpreted either as transverse MHD waves—possibly excited by jet precession, nutation, or quasiperiodic magnetic flux eruptions near the central engine—or as manifestations of jet instabilities, such as current-driven instabilities. Further investigation is required to distinguish between these scenarios and to clarify the dominant physical mechanism.

Keywords: Supermassive black holes, Magnetohydrodynamics, Very long baseline interferometry, Relativistic jets, Radio continuum emission, Radio active galactic nuclei
Modeling the Time-variable Broadband Emission and Correlation Study of FSRQ S5 1044+71. We present a detailed temporal and spectral analysis of the blazar S5 1044+71 using multiwavelength data obtained from the Fermi-LAT and Swift-XRT/UVOT telescopes. Applying the Bayesian block algorithm to the 3-day binned γ-ray light curve, we identify pronounced variability, including four major outbursts marked by significant flux enhancements. The highest flux recorded was (1.1 ± 0.2) × 10−6 photons cm−2 s−1 on 57868.5 MJD. Each outburst comprises multiple components, and light-curve profile analysis indicates predominantly symmetric temporal structures. The shortest variability timescale of 4.5 hr constrains the emission region to be located within 0.03 pc of the central engine, likely near the broad-line region (BLR). Additionally, two highest-energy photons were detected with energies of 46.4 GeV (on 57739.6 MJD) and 42.5 GeV (on 59161.9 MJD), observed outside the peak flaring activity. The fractional variability shows an overall increasing trend from UV/optical to γ-ray bands, with a noticeable dip in the X-ray range, consistent with the shape of the broadband spectral energy distribution (SED). The flux distributions during flares exhibit lognormal or double-lognormal behavior, suggesting multiplicative variability processes and evolving emission zones. Cross-correlation analysis reveals a strong positive correlation between the γ-ray and X-ray bands, with X-rays lagging by 42.5 days. Broadband SED modeling across different flux states supports a one-zone leptonic scenario, with γ-ray emission produced via external Compton scattering of IR and BLR photons. High flux states show harder electron spectra, elevated break energies, and reduced magnetic fields—features consistent with efficient particle acceleration and Compton dominance.

Keywords: Blazars, Active galaxies, Non-thermal radiation sources, Relativistic jets
Deep-learning-based Identification of Solar Magnetic Tornadoes and Their Spatial Properties during Solar Minimum and Maximum. Solar magnetic tornadoes are dynamic, spiral-shaped plasma structures characterized by helical magnetic fields and rotating plasma flows in the solar atmosphere. They play a significant role in the transport of energy and mass within the solar environment. Identifying and analyzing solar magnetic tornadoes is challenging due to their transient nature and complex morphology and the large volume of associated observational data. We propose two automated methods for detecting these magnetoplasma structures using modern deep learning techniques. Our models search for twisted prominences in the solar corona visible at the solar limb. Our approach involves analyzing the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å images using convolutional and recurrent neural networks. By applying established techniques, the methods proposed can detect previously unknown magnetic tornadoes alongside those documented in the literature. The models are trained on 10,294 instances, which corresponds to detection of ∼100 tornadoes with high precision and recall. Identification of 1,476,885 new instances is performed. The resulting database allows for the first comparative analysis of magnetic tornadoes' spatial distributions across solar cycle phases. We find that tornadoes can serve as tracers of environments prone to reconnection. During solar minimum, these structures occur at the boundaries of coronal holes with strong current sheets and at the edges of polar conic current sheets. During solar maximum, they appear at the footpoints of magnetic loops and are associated with polarity inversion lines.

Keywords: Solar atmosphere, Interdisciplinary astronomy, Computational astronomy, Solar prominences
Numerical Exploration of a B-Class Flare Using the Synergy between XSM, GOES, AIA, and HMI. Solar flares are sudden, explosive events on the Sun in which magnetic energy, ranging from 1023 to 1032 erg, is released in the form of heat and acceleration of charged particles, along with a rearrangement of magnetic field lines by magnetic reconnection. Energetically large flares affect the near-Earth space weather and have been extensively studied. In contrast, microflares and nanoflares are relatively less explored, since their detection requires more sensitive observations. However, a systematic and holistic study of these flares can contribute to the physics of small-scale energy release events and to their role in research problems related to both chromospheric and coronal heating. Consequently, this paper investigates magnetic reconnection in a Geostationary Operational Environmental Satellite (GOES) B-class flare, loosely classified as a microflare, using multi-instrument data and 3D data-constrained magnetohydrodynamics (MHD) simulations. Light curves of the Solar X-ray Monitor (XSM) and GOES are compared, showing that preflare (phase-1) and impulsive phases (phase-2) of the flare are better resolved by XSM. Non-force-free field extrapolations of the host active region (AR12759) reveal two hyperbolic flux tubes (HFTs). To understand the reconnection details of phase 1 and phase 2, data-constrained MHD simulations are carried out using the extrapolated data as input to the MHD code—EULAG-MHD, identifying one of the HFTs as the reconnection site of the observed flare. Furthermore, a comparison of the two phases is made, suggesting a near similarity in terms of the reconnection mechanism and dynamics of reconnected field lines; however, details of energetics—particularly dissipation and the conversion of magnetic energy to kinetic energy—are different.

Keywords: Solar flares, Solar magnetic reconnection, Magnetohydrodynamical simulations
In-depth Analysis of Bar Formation Mechanisms of Disk Galaxies in Halos of Different Concentrations. We use N-body simulations to investigate the distinct bar formation processes in disks residing in halos of various concentrations. In a highly concentrated halo, the bar development is limited by the dominant multiarm modes as a result of the swing amplification in the early stage. After the multiarm modes decay, the bar growth proceeds mechanically owing to the particle trapping in continuation of that bar seed. In this scheme, the corotation resonance of the bar modes does not come into play at all, justified by a low amount of disk─halo angular momentum transfer and a modestly decreasing bar pattern speed. On the other hand, although reducing the halo concentration suggests the reduction of the preferred swing-amplified modes to be bisymmetric, the bar formation in a low-concentration halo does not involve the swing amplification at all. Rather, the fast-growing linearly unstable bar modes of a single uniform frequency are the sole governing factor, attributed to a mild shearing. The bar modes have triggered the corotation resonance since the beginning, and such resonance is maintained until the end, which leads to a high amount of angular momentum transfer and a fast slowdown. For the intermediate halo concentration, the kinematical analyses of multiple nonaxisymmetric modes suggest that the linear modes, the swing amplification, and the particle trapping are all present in the evolution chronology. To specify bars formed in the different halo concentrations, full analyses of the isophotal shape, the radial Fourier amplitude, and the resonance diagram can be of use.

Keywords: Galaxy dynamics, Galaxy evolution, Barred spiral galaxies, N-body simulations, Galactic bar