Sazuna/UAT_keywords huggingface dataset:
Environmental Effects and Size─Mass Relations of Red Disk Galaxies at 0.1 &lt; z &lt; 0.5. Red disk galaxies (RDGs), as a minority population in the process of galaxy evolution, have attracted considerable attention, due to the decoupling between color and morphological evolution. From the DESI Legacy Imaging Surveys, we construct an RDG sample of 75,170 galaxies and a control sample of ∼2.6 million blue disk galaxies (BDGs) at 0.1&lt; z &lt; 0.5. The RDGs exhibit a more compact structure, with a smaller size at a fixed stellar mass, manifested in the size─mass relation as a significant difference in the intercept between BDGs and RDGs. Additionally, we obtain a BDG subsample with similar mass distribution to the RDG sample through a mass-matching algorithm, and their size─mass relations exhibit similar slopes, implying that the RDGs and BDGs may have similar mass growth histories. Our analysis of the size─mass relations in cluster and field environments at 0.1 &lt; z &lt; 0.3 reveals significant environmental differences, supporting a scenario where RDG formation is driven by environmental mechanisms like ram pressure and tidal stripping. This is consistent with the observed higher RDG abundance in clusters. Overall, our results suggest that RDGs may be descendants of massive BDGs. The evolution of BDGs into RDGs is primarily driven by the asynchrony between color transformation and morphological evolution, a process accelerated by mergers, "downsizing," ram pressure, and tidal interactions.

Keywords: Disk galaxies, Galaxy environments, Galaxy evolution, Stellar masses, Galaxies
Magnetic Field Configuration of a Quiescent Prominence Revealed by Large-amplitude Longitudinal Oscillations in End-view Observations. Prominence seismology, applied to large-amplitude longitudinal oscillations, is used to indirectly diagnose the geometry and strength of the magnetic fields inside the prominence. In this paper, combining imaging and spectroscopic data, the magnetic field configuration of a quiescent prominence is revealed by large-amplitude longitudinal oscillations observed in end view on 2023 December 4. In particular, the prominence oscillation involved blueshift velocities in Dopplergrams and horizontal motions in extreme-ultraviolet images. Originally, the prominence oscillation was triggered by the collision and heating of an adjoining hot structure associated with two coronal jets. The oscillation involved two groups of signals with similar oscillatory parameters, a three-dimensional (3D) initial amplitude of ∼40 Mm and a 3D velocity amplitude of ∼48 km s−1, both lasting for ∼4 cycles with a period of ∼77 minutes, with a phase difference of ∼π/8. The angle between the 3D velocities and the prominence axis ranges from 10∘ to 30∘. Two methods, utilizing time─distance diagrams and velocity fields, are employed to calculate the curvature radius of magnetic dips supporting the prominence materials. Both methods yield similar value ranges and trends from the bottom to the top of magnetic dips, with the curvature radius increasing from ∼90 Mm to ∼220 Mm, then decreasing to ∼10 Mm, with transverse magnetic field strength ≥25 Gauss. From this, the realistic 3D geometry of the prominence magnetic dips is determined to be sinusoidal. To the best of our knowledge, we present the first accurate calculation of the 3D curvature radius and geometry of the prominence magnetic dips based on longitudinal oscillatory motions.

Keywords: Solar activity, Quiescent solar prominence, Solar prominences, Solar oscillations
3D Non-equilibrium Ionization and Spectroscopic Modeling of Coronal Mass Ejections. II. CME Energy Budget. Coronal mass ejections (CMEs) release between ≍1030 and 1033 erg of energy into the corona; however, their detailed energy budget is difficult to constrain. In the first paper of the series, we used a magnetohydrodynamics (MHD) model to simulate the 2008 April 9 CME ("Cartwheel CME") and its Hinode/Extreme ultraviolet Imaging Spectrometer observations at 1.1 R⊙, performing a detailed analysis of the thermodynamic evolution during the initial acceleration period. This is the first global MHD simulation of a CME to include self-consistent prediction of charge states and nonequilibrium ionization spectra. In this second paper, we extend the results to investigate the energy budget evolution during the Cartwheel CME's initial acceleration period by analyzing the 3D global structure and tracking multiple plasma parcels to examine their energy evolution. Early in the eruption, 70% of the magnetic energy stored in the flux rope either dissipates to the thermal or is converted to kinetic energy, while about 30% of the energy is lost primarily to radiation. The protons are preferentially heated in the sheath by increased Alfvén wave energy dissipation. An extended current sheet forms out to 1.6 R⊙, resulting in reconnection, which drives a hot jet along the backside of the flux rope. The prominence material remains cold beyond 10 R⊙, due to large radiative cooling rates.

Keywords: Magnetohydrodynamics, Solar coronal mass ejections
Shooting for the Stars: Jet-mode Feedback and AGN Jet Deceleration from Stellar Mass Loading. Active Galactic Nucleus (AGN) jets are thought to be vital ingredients in galaxy evolution through the action of kinetic feedback; however, how narrow, relativistic outflows couple to galaxies remains an open question. Jet deceleration, which is often attributed to the entrainment of material, such as stellar winds, is thought to be necessary for efficient coupling. We present a simple model of jet deceleration due to stellar mass-loading to investigate the energy budget of direct jet feedback in the local Universe. To this end, we produce models of stellar mass loss, including deriving a prescription for main-sequence mass-loss rates as a function of stellar population age. We pair this mass-loss data with a parametric fit for radio AGN incidence, predicting that a majority of jets are decelerated within their hosts, and generally replicate the expected FR-II fraction in LERGs. We calculate that ≳25% of the jet power in the local Universe is efficiently decelerated and available for direct feedback within galaxies for any stellar population age. This fraction is largely invariant to the shape of the radio AGN incidence function at low jet Eddington fractions. The stellar mass-loss rate evolves significantly over time, approximately following τ−1.1, leading to corresponding decreases in decelerated jet power in older stellar populations. Although asymptotic giant branch stars dominate mass loss at all ages, we find that their stochasticity is important in low-mass galaxies, and derive a critical jet power below which main-sequence stars alone are sufficient to decelerate the jet.

Keywords: Active galaxies, Galaxy jets, Stellar mass loss
Continuous Gravitational Waves from Magnetized White Dwarfs: Quantifying the Detection Plausibility by LISA. White dwarfs (WDs) are frequently observed to have strong magnetic fields up to 109 G and expected to have a possible internal field as high as ∼1014 G. High internal fields can significantly deform a WD's equilibrium structure, generating a quadrupole moment. If the rotation axis is misaligned with the magnetic axis, the deformation can lead to the emission of continuous gravitational waves (CGWs). We examine the potential for detecting CGWs from magnetized WDs with future space-based detectors such as LISA, ALIA, DECIGO, Deci-Hz, the Big Bang Observer, and TianQin. We model the field-induced deformation and compute the resulting GW strain, incorporating amplitude decay due to angular momentum loss from electromagnetic and gravitational radiation. This sets a timescale for detection—an "active timescale" of 105−106 yr, requiring observation while the object remains sufficiently young. Our results suggest that LISA could detect a few dozen highly magnetized WDs across the Galaxy during its mission. As a specific case, we investigate ZTF J1901+1458—a compact, massive, fast-rotating, and strongly magnetized WD with spin period ∼416 s and inferred surface field ∼109 G. We find that this object would be detectable by LISA with 4 yr of continuous data. This highlights the potential of CGW observations to probe magnetic field structure in WDs and their role in Type Ia supernova progenitors.

Keywords: Stellar structures, White dwarf stars, Stellar magnetic fields, Gravitational wave sources, Astronomical simulations, Astronomical radiation sources
Molecular Gas in Major Mergers Hosting Dual and Single AGNs at &lt;10 kpc Nuclear Separations. We present high-resolution (∼50─100 pc) Atacama Large Millimeter/submillimeter Array observations of 12CO(2─1) or 12CO(1─0) emission in seven local (z ≲ 0.05) major mergers—five of which are dual active galactic nucleus (AGN) systems, and two of which are single AGN systems. We model the molecular gas kinematics through rotating disk profiles using a Bayesian Markov Chain Monte Carlo approach. The residuals were then used to isolate nonrotating components of the molecular gas—the most likely contributor to future supermassive black hole (SMBH) growth. We find that more-massive SMBHs have higher surface densities of nonrotating molecular gas within their sphere of influence. This potential molecular gas supply, however, does not correlate with the current accretion efficiency of the SMBHs, suggesting that only a fraction of the observed nonrotating gas is currently reaching the SMBH. Finally, we tentatively find no significant differences in the nuclear molecular gas masses of single-AGN and dual-AGN hosts, both within the SMBH sphere of influence and within the central kiloparsec. Our results indicate that the probability of occurrence of the dual AGN phenomenon is likely dependent on AGN variability and/or obscuration rather than the availability of molecular gas in the nuclear regions.

Keywords: Molecular gas, Active galaxies, Galaxy interactions, Active galactic nuclei, Galaxy mergers
Turbulence in Core-collapse Supernovae. It is understood in a general sense that turbulent fluid motion below the shock front in a core-collapse supernova stiffens the effective equation of state of the fluid and aids in the revival of the explosion. However, when one wishes to be precise and quantify the amount of turbulence in a supernova simulation, one immediately encounters the problem that turbulence is difficult to define and measure. Using the 3D magnetohydrodynamic code ELEPHANT, we study how different definitions of turbulence change one's conclusions about the amount of turbulence in a supernova and the extent to which it helps the explosion. We find that, while all the definitions of turbulence we use lead to a qualitatively similar growth pattern over time of the turbulent kinetic energy in the gain region, the total amount of turbulent kinetic energy, and especially the ratios of turbulent to total kinetic energy, distinguish them. Some of the definitions appear to indicate turbulence is a necessary contributor to the explosion, and others indicate it is not. The different definitions also produce turbulence maps with different correlations with maps of the enstrophy, a quantity widely regarded as also indicating the presence of turbulence. We also compute the turbulent adiabatic index and observe that, in regions of low enstrophy, this quantity is sensitive to the definition used. As a consequence, the effective adiabatic index depends upon the method used to measure the turbulence, and thus it alters one's conclusions regarding the impact of turbulence within the supernova.

Keywords: Computational astronomy, Supernova dynamics, Core-collapse supernovae
On the Frequency of Multiple Galaxy Mergers in ΛCDM Cosmological Simulations. Mergers are believed to play a pivotal role in galaxy evolution, and measuring the galaxy merger fraction is a longstanding goal of both observational and theoretical studies. In this work, we extend the consideration of the merger fraction from the standard measure of binary mergers, namely those comprising two merging galaxies, to multiple mergers, namely mergers involving three or more galaxies. We use the Illustris and IllustrisTNG cosmological hydrodynamical simulations to provide a theoretical prediction for the fraction of galaxy systems that are involved in a multiple merger as a function of various parameters, with a focus on the relationship between the multiple merger fraction fm and the total merger fraction ft. We generally find that binary mergers dominate the total fraction and that  fm≍(0.5−0.7)ft5/3 , a prediction that can be tested observationally. We further compare the empirical simulation results with toy models where mergers occur, on the evolution timeline of a galaxy, either at constant intervals or as a Poisson process at a constant rate. From these comparisons, where the toy models typically produce lower multiple merger fractions, we conclude that in cosmological simulations, mergers are more strongly clustered in time than in these toy scenarios, likely reflecting the hierarchical nature of cosmological structure formation.

Keywords: Hydrodynamical simulations, Galaxy collisions, Large-scale structure of the universe, Galaxy mergers, N-body simulations
The ALMA-ATOMS-QUARKS Survey: Resolving a Chemically Rich Massive Protostellar Outflow. We present a comprehensive study on the physical and chemical structures of a chemically rich bipolar outflow in a high-mass star-forming region IRAS 16272−4837 (SDC335), utilizing high-resolution spectral line data at 1.3 and 3 mm dual bands from the Atacama Large Millimeter/submillimeter Array, ATOMS, and QUARKS surveys. The high-velocity jet is enveloped by a lower-velocity outflow cavity, containing bright knots that show enhanced molecular intensities and elevated excitation temperatures. Along the outflow, we have identified 35 transitions from 22 molecular species. By analyzing the spatial distribution and kinematics of these molecular lines, we find that the molecular inventory in the outflow is regulated by three processes: (i) direct entrainment from the natal molecular core by the outflow; (ii) shock-induced release of molecules or atoms from dust grains; and (iii) thermal desorption and gas-phase reactions driven by shock heating. These results confirm that outflows are not only dynamical structures but also active chemical factories, where entrainment, shocks, and thermal processing jointly enrich the molecular content. Our findings confirmed that outflow chemistry has a multiorigin nature, and provide critical insights into chemical evolution during high-mass star formation.

Keywords: Stellar jets, Star forming regions, Astrochemistry, Star formation, Protostars
Magnetically Driven Retrograde Precession in Misaligned Black Hole Accretion Flows. Observations of accreting black hole (BH) systems, such as microquasars and supermassive BHs, often reveal a precessing jet with changing directions, indicating a misaligned accretion flow relative to the BH spin. The precession is commonly attributed to the Lense─Thirring (LT) effect, which arises from the BH's rotation twisting the surrounding spacetime and accretion flow. In the strongly magnetized regime, characteristics of low-luminosity active galactic nuclei and other systems that launch powerful jets, the large-scale magnetic field can significantly influence the flow dynamics. Here, we perform large-scale three-dimensional general relativistic magnetohydrodynamic simulations of tilted accretion onto a rotating BH and find a never-seen-before new retrograde precession. This precession arises from a magnetic torque on the disk generated by the poloidal magnetic field aligned with the BH's rotation, opposing the LT torque. This finding highlights the unique property of highly magnetized accretion flows around BHs and provides a new interpretation of jet precession observed in many systems.

Keywords: Accretion, Jets, Magnetic fields, Astrophysical black holes, Magnetohydrodynamical simulations
Fast Inflowing Ionized Absorber Tracing the Gas Dynamics at Subparsec Scale around Mrk 3. Accretion onto a supermassive black hole can release energy via radiation, jets, or winds, providing feedback effects on the circumnuclear gas environment. However, not all active galactic nuclei exhibit clear signatures of such feedback, and the dynamics of accreting gas on the inner subparsec scales remains poorly understood. Using high-resolution Chandra X-ray grating spectra of Mrk 3, we detect a fast inflowing ionized absorber characterized by redshifted Fe XXV and Fe XXVI absorption lines with confidence level in the 94%─99.6% range. Photoionization modeling reveals the inflowing absorber is located at ≲0.04─0.74 pc, with redshifted velocity decreasing from 6.1 ± 0.5 × 103 km s−1 to 3.4 ± 0.3 × 103 km s−1 over 11 yr. Only ∼0.6%─3% of the inflowing material is estimated to reach the event horizon. This direct evidence of subparsec scale fueling inflow bridges the gap between the torus and the outer accretion disk. Additionally, a 0.86 keV gas component with subsolar metallicity (Z ∼ 0.22), outflowing at a velocity of ∼330 km s−1, is detected in the soft X-ray band with the XMM-Newton Reflection Grating Spectrometer, probably corresponding to a shocked interstellar medium in the narrow-line region (NLR). The simultaneous presence of the apparent decelerating subparsec inflow and the NLR outflow favors a coherent scenario where a putative disk wind or broad-line region clouds may impede or even eject the accretion material, although other possibilities cannot be fully excluded.

Keywords: Accretion, Photoionization, X-ray active galactic nuclei, High energy astrophysics
Theoretical Models for the Late Thermal Pulse in Post-asymptotic Giant Branch Stars: The Case of DY Cen. We present theoretical predictions of the born-again scenario for post-asymptotic giant branch stars. An extensive model grid for born-again objects has been constructed, particularly including models for the very late thermal pulse with and without convective overshooting and also including models for the late thermal pulse. We constructed a large parameter space to analyze the dependencies of the born-again model on core mass, hydrogen-envelope mass, and overshoot parameters, and we analyzed how changes in these parameters affect the models' evolution. We applied our grid of models to interpret observations of DY Cen, a star exhibiting characteristics similar to confirmed born-again stars. We compared DY Cen with models from multiple aspects, including heating rate, evolutionary tracks, and surface abundances. Ultimately, we concluded that none of our born-again models could match all of the observed properties of DY Cen, especially its surface chemistry; DY Cen is therefore an unlikely born-again star.

Keywords: Post-asymptotic giant branch stars, Stellar evolutionary models, Asymptotic giant branch stars, Nonstandard evolution, Stellar evolution
Bouncing Grains Keep Protoplanetary Disks Bright. Protoplanetary disks display the so-called size─luminosity relation, where their millimeter wavelength fluxes scale linearly with their emitting areas. This suggests that these disks are optically thick in millimeter band, an interpretation further supported by their near-blackbody spectral indexes. Such characteristics are seen not only among disks in very young star-forming regions like Lupus (1─3 Myr), but, as we demonstrate here, also among disks in the much older Upper Scorpius region (5─11 Myr). How can disks shine brightly for so long, when grain growth and subsequent radial drift should have quickly depleted their solid reservoir? Here, we suggest that the "bouncing barrier" provides the answer. Even colliding at very low speeds (below 1 cm s−1), grains already fail to stick to each other but instead bounce off in elastically. This barrier stalls grain growth at a near-universal size of ∼100 μm. These small grains experience much reduced radial drift, and so are able to keep the disks bright for millions of years. They are also tightly coupled to gas, offering poor prospects for processes like streaming instability or pebble accretion. We speculate briefly on how planetesimals can arise in such a bath of 100 μm grains.

Keywords: Dust physics, Protoplanetary disks
Molecular Hydrogen in High-redshift Damped Lyα Absorbers. Simulations predict that circumgalactic hydrogen gas surrounding massive ( Mhaloz=1=1012−1013M⊙ ) galaxies at z ∼ 4 may be predominantly neutral and could produce damped Lyα absorbers (DLAs) along sight lines to background quasars. A circumgalactic medium (CGM) origin for DLAs naturally explains H I absorption-selected galaxy detections at z ∼ 4 with physical separations much greater than the likely extents of the galaxy disks. These H I column densities observed in z ∼ 4 DLA are large and comparable to interstellar (ISM) gas columns at which substantial molecular hydrogen (H2) abundances occur. We therefore investigate the possible molecular content of high-redshift CGM gas and its potential detectability via (rest-frame) far-ultraviolet (UV) absorption-line studies. For this purpose, we develop an analytic subgrid model for H I-to-H2 transitions and incorporate the model with zoom-in FIRE-2 simulations of evolving high-z galaxies. We include dust absorption and scattering computations for the transfer of photodissociating Lyman─Werner-band radiation. We find that the typical extents of detectable H2 sightlines are ≍0.1 Rvir, independent of redshift from z = 2.5 to 5. We argue that a CGM origin for DLAs naturally explains the low detection rates of H2 in DLA observations, as the low CGM densities and relatively strong far-UV fields lead to molecular fractions much lower than observed in the ISM at comparable H I columns.

Keywords: Hydrodynamical simulations, Damped Lyman-alpha systems, Astrochemistry, Galaxy evolution, Circumgalactic medium
Disentangling Thermal and Abundance Characteristics in a Solar Flare Using SDO/AIA, Hinode/XRT, and MinXSS-1 Observations. We investigate the thermal properties of a solar flare by the observations of the soft X-ray Telescope on board Hinode and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. Our analysis reveals a tenuous but hot plasma cloud located above the flare loops. The flare loops and plasma cloud exhibit independent temperature profiles as a function of time, implying that different heating mechanisms are present in these structures. We interpret the plasma cloud as an eruptive filament directly heated in the corona via magnetic reconnection that occurs when a rising filament interacts with this eruptive filament. Previous disk-integrated solar soft X-ray spectral measurements of this flare using the Miniature X-ray Solar Spectrometer CubeSat-1 (MinXSS-1) inferred coronal abundances at the flare peak. However, MinXSS synthetic spectra from AIA observations show that the plasma cloud is too tenuous to be detected in MinXSS-1; thus, the coronal abundances of low first ionization potential elements must be in emission from the flare loops. Furthermore, we demonstrate the nonnegligible differences in differential emission measures between coronal and photospheric abundance models. These results highlight the importance of instruments capable of simultaneous spectral and spatial diagnostics during large-scale solar events. Such coordinated measurements would enable more accurate thermal and compositional analyses and deeper insight into the underlying physical mechanisms.

Keywords: Solar flares, Solar abundances, Solar corona, Solar filament eruptions, Solar activity