Sazuna/UAT_keywords huggingface dataset:
The Rotation Dip in the Envelope─Disk Transition of HH 111: Evidence for Magnetic Braking. Magnetic braking can drive angular momentum loss in star formation and influence disk evolution. A previous study of HH 111 VLA 1 suggested a decrease in rotation velocity in a region between the infalling envelope and rotating disk. Using Atacama Large Millimeter/submillimeter Array C18O (J = 2─1) data, we analyzed the gas motion within 6000 au and found clear deviations from the simplest expectations of freefall toward the central star with conserved angular momentum in the transition region between the envelope and disk (from ∼5200 to 160 au). The region can be further divided into three zones: (1) outer region with a significant decrease in infall velocity, dropping to approximately 60% of the freefall velocity and 70% of conservation of angular momentum and energy; (2) middle region with a sharp drop in angular momentum and thus rotation velocity and an increase in infall velocity; and (3) inner region with rotation velocity increasing inward to connect to that of the Keplerian disk and infall velocity decreasing to zero. Comparison with nonideal MHD simulations suggests that the reduced infall velocity in the outer region can be due to magnetic tension by the pinched magnetic field lines, the sharp drop of angular momentum in the middle region can be due to magnetic braking as the field lines pileup, and the rapid increase in rotation velocity in the inner region might result from weaker magnetic braking due to ambipolar diffusion of the field lines. The resulting dip in the rotation profile supports magnetic braking.

Keywords: Circumstellar envelopes, Star formation, Stellar accretion disks, Protostars, Radio astronomy
Galaxy Spin Alignment with Tidal Fields in the SDSS-IV MaNGA Survey. The tidal torque theory (TTT) predicts that galaxy spins are correlated with the surrounding tidal field, reflecting how angular momentum is acquired during structure formation. We present a new observational test of this prediction using the final data release of the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory integral field spectroscopy survey, which enables direct spin measurements from stellar and ionized gas kinematics for a sample of 6325 disk galaxies. We utilize the three-dimensional tidal field reconstructed from the galaxy distribution, providing a physically defined reference frame for the analysis. We find that massive galaxies tend to align their spins parallel to the intermediate axis of the tidal field, consistent with the prediction of the TTT, while also showing a tendency to align perpendicular to the major axis. In contrast, low-mass galaxies exhibit the opposite trend, with a transition mass of M* ∼ 1010─1010.5 M⊙. No significant alignment is detected with respect to the minor axis across all stellar masses. We further examine the dependence on morphology and environment, finding that S0 and early-type spiral galaxies exhibit stronger alignment signals than late-type spirals. The alignment trend becomes particularly pronounced in regions of high tidal anisotropy and high overdensity. A mutual information analysis identifies these environmental factors as the dominant drivers of the observed trends. Our results provide new empirical evidence for the connection between galaxy spins and the cosmic tidal field.

Keywords: Galaxy kinematics, Large-scale structure of the universe
The Cosmic Dance: Observational Detection of Coherent Spin in Galaxy Clusters. The spin of galaxy clusters encodes key information about their formation, dynamics, and the influence of large-scale structure. However, whether clusters possess statistically significant spin and how to measure it observationally remain open questions. Here, we present the first observational, statistical detection of coherent spin in galaxy clusters, using two samples of 2170 and 1329 systems with M &gt; 1014 M⊙, selected from two publicly available group catalogs constructed with two different algorithms and but both based primarily on Sloan Digital Sky Survey galaxies. Cluster spin is quantified by identifying the orientation in the projected plane that maximizes the redshift difference ( ∆Zmax ) between member galaxies in two regions divided by a trial axis. We find compelling statistical evidence for coherent rotation, as the observed  ∆Zmax  distribution departs markedly from the randomized controls, exhibiting pronounced deviations near 380 km s−1. Stacked visualizations confirm the spatial segregation of redshifted and blueshifted galaxies across the rotation axis. The radial profile of the rotational velocity indicates that it increases as a function of radius. The cluster rotation speed increases with mass, from ∼360 km s−1 at 1014M⊙ to ∼693 km s−1 at 1015M⊙. Additionally, cluster spin tends to align parallel with the central galaxy spin and perpendicular to the nearest cosmic filament, particularly in richer systems. These results reveal significant coherent spin in galaxy clusters, shaped by both internal dynamics and large-scale structure.

Keywords: Galaxy clusters, Astrostatistics, Large-scale structure of the universe
Chemically Primitive Dwarf Accretion Reignites the Inner Disk Assembly of Malin 1. We present a detailed kinematic and stellar population analysis of the inner disk of Malin 1, a giant low surface brightness galaxy with a prominent SB 0-type central morphology. AstroSat far-ultraviolet (FUV) imaging reveals clumpy emission features indicating recent star formation. Using MUSE integral field spectroscopy, we identify four star-forming complexes (SFCs) within the inner 10 kpc, each associated with localized ionized gas emission in distinct Hα velocity channels. Two of the SFCs, including a FUV clump, appear on the blueshifted side (VHα = −230 km s−1), while the other two are redshifted. The FUV clump shows a strong velocity offset (∼150 km s−1) and high gas dispersion (∼250 km s−1), indicating that it is kinematically decoupled from the rotating disk. The spatial and velocity isolation of these features in the channel map confirms they do not follow regular disk rotation. The FUV clump hosts young (250─500 Myr), extremely metal-poor ([M/H] ≃ −1.69) and α-enriched ([α/Fe] ∼ 0.5) stellar populations, sharply contrasting with the surrounding supersolar gas-phase metallicity. The young stellar populations in each SFC are chemically distinct (similar to the FUV clump) from the enriched central interstellar medium (ISM), indicating rapid, local star formation from primitive gas before efficient mixing with the enriched ISM. Their spatial and velocity segregation, age synchronicity, and chemical homogeneity suggest an origin of gas delivered by a disrupted, gas-rich dwarf on a high-inclination (off-plane) orbit. These results suggest that the central HSB within ∼9″ (14 kpc) radius component of Malin 1 has grown through discrete, externally driven accretion, contributing to its complex, hybrid disk morphology.

Keywords: Disk galaxies, Galaxy chemical evolution, Galactic archaeology, Galaxy kinematics, Low surface brightness galaxies
A Remote Brightening from Interactions between an Extreme-ultraviolet Jet and a Magnetic Null. Remote brightening (RB) refers to brightening at a footpoint of magnetic loops in the solar atmosphere, which is passively triggered by an eruption occurring at the other footpoint. Here, we present observations of an RB event driven by an extreme-ultraviolet (EUV) jet. The leading front of the jet exhibits flows exceeding the characteristic sound speed, and it triggers RBs at two remote sites that are connected by coronal loops. We focus on the RB that occurred at one of the footpoints, in which the magnetic structure is characterized by a dome-like feature with magnetic null points. When the jet propagates to this footpoint, the brightening displays a distinct inverted-Y-shaped structure. Bidirectional flows with a velocity of about 30 km s−1 are detected in any two branches of this structure, which are suggestive of the occurrence of magnetic reconnection at this footpoint. To investigate the physics of the interaction between the jet and the remote magnetic null point, we conducted a 2D MHD simulation with adaptive mesh refinement. We find that the collapse of the magnetic null point is induced by a fast-mode wave, and the flow associated with the jet elongates the current sheet, thereby triggering plasmoid instability. Subsequent magnetic reconnection not only forms the bright inverted-Y-shaped structure but also drives bidirectional flows along the structures, being consistent with the observational findings. This study provides new insights into the dynamic interaction between EUV jets and remote magnetic nulls in the solar atmosphere, and helps understand the diverse natures of RBs.

Keywords: Solar atmosphere, Solar magnetic reconnection, Plasma jets, Solar coronal heating, Solar coronal waves, Solar corona, Magnetohydrodynamical simulations
A XRISM View of Relativistic Reflection in Cygnus X-1. We present the first high-resolution XRISM/Resolve view of the relativistically broadened Fe K line in Cygnus X-1. The data clearly separate the relativistic broad line from the underlying continuum and from narrow emission and absorption features in the Fe band. The unprecedented spectral resolution in the Fe K band clearly demonstrates that the flux excess can be attributed to a single, broad feature, as opposed to a superposition of previously unresolved narrow features. This broad feature can be best interpreted as emission consistent with an origin near the innermost stable circular orbit around a rapidly rotating black hole. By modeling the shape of the broad line, we find a black hole spin of a ≃ 0.98 and an inclination of the inner accretion disk of θ ≃ 63∘. The spin is consistent with prior reflection studies, reaffirming the robustness of past spin measurements using the relativistic reflection method. The measured inclination provides reinforcing evidence of a disk-orbit misalignment in Cygnus X-1. These results highlight the unique abilities of XRISM in separating overlapping spectral features and providing constraints on the geometry of accretion in X-ray binaries.

Keywords: X-ray binary stars, Black holes, Kerr black holes, High mass x-ray binary stars, Stellar mass black holes, Rotating black holes, Astrophysical black holes
Dynamical Simulation of the Interstellar Comet 3I/ATLAS. Comet 3I/ATLAS, also known as C/2025 N1, was discovered on 2025 July 1 UT by NASA Asteroid Terrestrial-impact Last Alert System (ATLAS), with a v∞ ∼ 58 km s−1. This is the fastest among the three interstellar objects discovered so far. In this work, we study the interaction of 3I/ATLAS with Mars preperihelion, and Jupiter postperihelion. We also present the results of the dynamical simulations of the orbital evolution of the comet for 100 yr in the past and future. For our analysis, we have used REBOUND, an N-body simulation package, to study these situations. We use the adaptive size mathematical integrator IAS15, with a 1 day time step for long-term integration, and a 1 hr time step to study the effect of the planets on this body during the close encounters. We have seen an effect of Jupiter on the orbital parameters of the comet, which affects its postperijove trajectory significantly. The impact of Mars on this comet is minimal compared to the effect of Jupiter. This is consistent with the point that the comet moves well past Mars's Hill radius but very close to Jupiter's Hill radius at the respective close approaches. However, the effect of nongravitational forces will alter the results. Since the nongravitational forces are not yet known, we predict the variation of the orbital parameters considering a range of possible magnitudes of the nongravitational acceleration.

Keywords: Comets, Comet dynamics, Interstellar objects, N-body simulations
XRISM Spectroscopy of the Stellar-mass Black Hole GRS 1915+105. GRS 1915+105 was the stellar-mass black hole that best reproduced key phenomena that are also observed in type 1 active galactic nuclei (AGNs). In recent years, however, it has evolved to resemble a type 2 or Compton-thick AGN. Herein we report on the first XRISM observation of GRS 1915+105. The high-resolution Resolve calorimeter spectrum reveals that a sub-Eddington central engine is covered by a layer of warm, Compton-thick gas. With the obscuration acting as a coronagraph, numerous strong, narrow emission lines from He-like and H-like charge states of Si, S, Ar, Ca, Cr, Mn, Fe, and Ni dominate the spectrum. Radiative recombination continuum (RRC) features are also observed, signaling that much of the emitting gas is photoionized. The line spectrum can be fit by three photoionized emission zones, with broadening and bulk velocities suggestive of an origin in the outer disk atmosphere and/or a slow wind at r ≃ 106GM/c2. The Fe XXV Heα and Fe XXVI Lyα lines have a broad base that may indicate some emission from r ∼ 3 × 103GM/c2. These results broadly support a picture wherein the current state in GRS 1915+105 is due to obscuration by the irradiated outer disk. This could arise through disk thickening if the Eddington fraction is higher than inferred, but it is more likely due to a warped, precessing disk that has brought the outer disk into the line of sight. We discuss the strengths and weaknesses of this interpretation and our modeling, as well as possible explanations of some potentially novel spectral features.

Keywords: X-ray binary stars, Black holes, High energy astrophysics, Stellar mass black holes, Low-mass x-ray binary stars
ATLAS Photometry of Interstellar Object 3I/ATLAS. We present calibrated Asteroid Terrestrial-impact Last Alert System (ATLAS) photometry of the interstellar comet 3I/ATLAS (C/2025 N1) from March 28 through 2025 August 29, obtained with the five-site, robotic ATLAS network in the c (420─650 nm), o (560─820 nm), and Teide w (420─720 nm) bands. Stacked difference images yield reliable light curves measured in four fixed apertures that capture the evolving coma. We observe 3I/ATLAS transitioning in color from red (c − o) ≍ 0.7 before MJD 60860 to near-solar (c − o) ≍ 0.3 after MJD 60870, coincident with the appearance of a prominent antisolar tail. The absolute magnitude curve H(t) shows a slope break near MJD 60890 at r ∼ 3.3 au from −0.035 to −0.012 mag day−1, or in terms of coma cross section as a function of heliocentric distance, r−3.9 to r−1.1. We release the aperture photometry with geometry and uncertainties to enable cross-instrument synthesis of 3I/ATLAS activity and color evolution.

Keywords: Interstellar objects
GRB 240715A: Revealing a Novel Intrinsic Mechanism by Different Individual Pulses. The Space-based multiband astronomical Variable Objects Monitor (SVOM) detected its first short gamma-ray burst (GRB), GRB 240715A, in flight, which was jointly observed by Fermi. Based on observational data of SVOM/GRM and Fermi/GBM, we perform a comprehensive temporal and spectral analysis of individual pulses in the prompt emission of this burst, and novel characteristics are revealed. First, opposite evolutions of spectral lag are found in the first and third pulse of this burst. Second, the large negative lag of the first pulse is an outlier in the short GRB sample, especially when the pulse duration is considered. Spectral analysis shows that the negative lag of the first pulse is caused by the evolution of the spectrum index and is irrelevant to Epeak, which is inconsistent with the previous study. The intrinsic mechanism is probably attributed to electron cooling in the decaying magnetic field, which leads to the continuous hardening of the spectrum index and results in negative lag. Furthermore, spectral analysis also shows that the third pulse is more likely to be described by a quasi-thermal spectrum, indicating the existence of photospheric emission. It is difficult to explain how the synchrotron radiation appears before photospheric emission in a single GRB, and some assumptions are discussed.

Keywords: Gamma-ray bursts
Discovery of SN 2025wny: A Strongly Gravitationally Lensed Superluminous Supernova at z = 2.01. We present the discovery of SN 2025wny (ZTF25abnjznp/GOTO25gqt) and spectroscopic classification of this event as the first gravitationally lensed Type I superluminous supernova (SLSN-I). Deep ground-based follow-up observations resolve four images of the supernova with  ∼1.″7  angular separation from the main lens galaxy, each coincident with the lensed images of a background galaxy seen in archival imaging of the field. Spectroscopy of the brightest image shows narrow features matching absorption lines at a redshift of z = 2.010 and broad features matching those seen in superluminous SNe with far-UV coverage. We infer a magnification factor of μ ∼ 20─50 for the brightest image in the system, based on photometric and spectroscopic comparisons to other SLSNe-I. SN 2025wny demonstrates that gravitationally lensed SNe are in reach of ground-based facilities out to redshifts far higher than previously assumed, and provide a unique window into studying distant supernovae and the internal properties of dwarf galaxies, as well as for time-delay cosmography.

Keywords: Gravitational lensing, Supernovae
GWTC-4.0: An Introduction to Version 4.0 of the Gravitational-Wave Transient Catalog. The Gravitational-Wave Transient Catalog (GWTC) is a collection of short-duration (transient) gravitational-wave signals identified by the LIGO─Virgo─KAGRA Collaboration in gravitational-wave data produced by the eponymous detectors. The catalog provides information about the identified candidates, such as the arrival time and amplitude of the signal and properties of the signal's source as inferred from the observational data. GWTC is the data release of this dataset, and version 4.0 extends the catalog to include observations made during the first part of the fourth LIGO─Virgo─KAGRA observing run up until 2024 January 31. This Letter marks an introduction to a collection of articles related to this version of the catalog, GWTC-4.0. The collection of articles accompanying the catalog provides documentation of the methods used to analyze the data, summaries of the catalog of events, observational measurements drawn from the population, and detailed discussions of selected candidates.

Keywords: Neutron stars, Gravitational wave detectors, Stellar mass black holes, Gravitational wave sources, Gravitational wave astronomy
The Dynamical Interaction between Low-mass Planets and Dust Coagulation. We investigate the impact of a low-mass planet on dust coagulation, and its consequent feedback on planetary migration, using a linear analysis of the coupled dust─gas hydrodynamic equations. Dust coagulation is incorporated via a single-size approximation. In the co-orbital region of the planet, we find that the growth of dust size is significantly suppressed by planet-induced coagulation modes (CMs). These effects are less pronounced with smaller stopping times, stronger gaseous turbulence, or imperfect sticking. Regarding planetary migration, we find that CMs make outward migration require τ ≳ 0.3 (τ is dimensionless stopping time) with typical turbulent strength and dust coagulation efficiency. We demonstrate that the torque variations are reasonable and arise from phase shifts between the density and stopping time perturbations in the coagulation modes.

Keywords: Planetary-disk interactions, Hydrodynamics, Protoplanetary disks, Planetary migration, Planet formation
Ocean Circulation on Tide-locked Lava Worlds: 3D Modeling with a Simple Boundary Iteration Method. Tide-locked lava worlds are surface-melted rocky planets under a 1:1 tidally locked orbit (i.e., synchronously rotating) with orbital period being equal to rotation period and with permanent hot dayside and cold nightside. Previous studies on this type of planets employed scaling analyses and two-dimensional (2D) simulations. This work is a continuation of the previous research but including the effect of the Coriolis force, and the simulation domain is extended to a 3D global sphere. We find that under the condition with thermal-only forcing (without surface wind stresses), the area-mean ocean depth is about 50─300 m (depending on vertical diffusivity) and the area-mean effect of horizontal ocean heat transport (in the order of 103─104 W m−2) is significantly smaller than stellar radiation (in the order of 106 W m−2 at the substellar region), being consistent with previous results. Different from 2D results, due to the effect of the Coriolis force, large-scale horizontal gyres form on the dayside; ocean currents near the west boundaries are much stronger than those near the east boundaries (called "western intensification"); the deepest ocean is not right at the substellar point but in the middle latitudes as the vertical diffusivity is moderate or large; and meanwhile, there exists significant asymmetry between the west and the east of the substellar point. These results establish the first picture of the 3D thermal-driven ocean circulation and confirm that the lava ocean should be shallow on tide-locked lava worlds.

Keywords: Exoplanet dynamics, Exoplanet surfaces, Exoplanets
Evolution of the Lithium─Rotation Correlation in Open Cluster F Dwarfs and a New Age Indicator. The Lithium Dip is a severe nonstandard depletion of surface Li in F dwarfs that occurs during the main sequence. We present Li and  vsini  measurements from WIYN/Hydra and CTIO/Hydra spectra of four open clusters whose ages span the range between that of the Pleiades (∼100 Myr), which shows little if any depletion, and that of the Hyades (∼650 Myr), where the dip was first detected. Restricting this study to include only single members for all six clusters plus Praesepe and M48 and using refined membership data such as those from Gaia DR2 lead to the following conclusions. The development of the Li dip is clearly seen. Each cluster shows a correlation between Li and  vsini  with little scatter. The slope of this correlation increases steadily with age, suggesting that the Li depletion and spin-down of these stars are related. This evolution of the lithium─rotation correlation suggests a new method for determining ages of Li-dip stars, which we explore. *This is Paper 96 of the WIYN Open Cluster Study.

Keywords: Stellar processes, Stellar ages, Stellar properties, Stellar abundances, Open star clusters, Stellar rotation, Stellar evolution