Sazuna/UAT_keywords huggingface dataset:
Consistent Modeling of Nonequilibrium Dust Sublimation and the Interactions with Dust Evolution in the Inner Regions of Protoplanetary Disks. The inner regions of protoplanetary disks are host to the sublimation of dust grains, a process traditionally modeled using equilibrium thermodynamics. We demonstrate through ab initio density functional theory and kinetic Monte Carlo simulations that silicate dust sublimation is inherently a nonequilibrium kinetic process. The binding energies and vibrational frequencies governing desorption, calculated for MgSiO3 and other compositions, reveal that sublimation timescales far exceed local dynamical times, allowing grains to persist in a superheated state. This kinetic inhibition results in a broad, dynamic sublimation front whose location and morphology are strongly regulated by radial advection and dust coagulation. Our coupled simulations, integrating sublimation with advection and grain evolution, show that the front varies radially by a factor of four with accretion rate and exhibits a vertically stratified, bowl-shaped structure. These findings imply that the inner disk's dust distribution, thermal structure, and subsequent planet formation are profoundly influenced by the kinematics and kinetics of dust grains, necessitating a departure from equilibrium prescriptions in disk models and interpretations of inner rim observations.

Keywords: Interstellar dust, Dust physics, Dust destruction, Astrophysical dust processes, Protoplanetary disks, Exoplanet formation
Ultradiffuse Galaxies in the EAGLE Simulation. We use the highest-resolution EAGLE simulation, Recal-L025N0752, to study the properties and formation of ultradiffuse galaxies (UDGs). We identify 181 UDGs at z = 0 and find their properties are consistent with observations. The total masses of the EAGLE UDGs range from ∼5 × 108 M⊙ to ∼2 × 1011 M⊙, indicating that they are dwarf galaxies rather than failed L⋆ galaxies. The EAGLE UDGs are not a distinct population, but rather a subset of dwarf galaxies, as their properties generally form a continuous distribution with those of normal dwarf galaxies. Unlike most of the situations in previous studies, the extended sizes of the field UDGs in EAGLE are not driven by high halo spins or by supernova-induced stellar expansion, but instead largely arise from high spins in their star-forming gas and thus the newly formed stars at large radii. We hypothesize that this might be attributed to galactic fountains, via which star-forming gas is launched to large halocentric distances and acquires additional angular momentum through interactions with the circumgalactic medium. For satellite UDGs, ∼60% of them were already UDGs before falling into the host galaxy, while the remaining ∼40% were normal galaxies prior to infall and subsequently transformed into UDGs due to tidal effects after infall.

Keywords: Hydrodynamical simulations, Galaxy formation, Dwarf galaxies, Low surface brightness galaxies
Ubiquity of Methanol and Its Related Chemical Segregation in Orion Starless Cores: The ALMASOP Sample. Complex organic molecules (COMs) in starless cores provide critical insights into the early stages of star formation and prebiotic chemistry. We present a chemical survey of 16 starless cores (including five prestellar cores) in the Orion A and B molecular clouds, targeting CH3OH, N2H+, CCS, and c-C3HD, using the Atacama Compact Array (ACA) and the Yebes 40 m telescope. CH3OH was detected toward all targets, confirming its ubiquity in starless cores, consistent with previous surveys in Taurus and Perseus. ACA imaging shows that CH3OH, CCS, and c-C3HD generally trace the outer layers of the dense cores outlined by N2H+, each exhibiting distinct spatial distributions. Meanwhile, comparison with Yebes data reveals an extended, flattened CH3OH component. CCS and c-C3HD tend to be detected or nondetected together across cores, while cores near dust-rich regions on a large scale often lack both, suggesting environmental influences linked to the interstellar radiation field. Within individual cores, CCS typically resides in an outer layer relative to c-C3HD. Our findings underscore the importance of high-resolution studies for understanding the origins and spatial differentiation of COMs and carbon-chain molecules in cold, quiescent environments.

Keywords: Star formation, Molecular clouds, Interstellar medium, Astrochemistry
Aspherical Remnants of Triple and Quadruple Detonations in Binary White Dwarfs. White dwarfs which explode by the double-detonation mechanism may have a binary white dwarf donor which is subsequently ignited by its collision with the ejecta. This results in the destruction of the donor via either the triple- or quadruple-detonation mechanism, adding significant mass to the resulting ejecta as well as modifying its structure and composition. We simulate the evolution of supernova remnants resulting from such detonations in a variety of binary progenitors and compare them against a double detonation with a surviving donor. Because of the time delay between the detonations of the two white dwarfs, high-velocity ejecta from the first explosion govern the first few centuries of remnant evolution, whereas at later times the dense core resulting from the donor detonation drives both the forward and reverse shocks to larger radii. The collision between the highest-velocity ejecta of the primary explosion and the donor carves a conical wake into the ejecta, which persists into the remnant phase regardless of whether or not the donor detonates. Our suite of simulated remnants is found to exhibit multiple distinguishing features of the explosion properties: a distinct X-ray morphology in the thermal emission and iron lines for triple detonations and smaller remnants with centrally concentrated emission for double detonations. The remnants are also varied in their elemental abundances and distributions, particularly for lighter elements, but these have limited observational utility and are sensitive to the properties of the progenitor binary.

Keywords: Supernova remnants, Type Ia supernovae, Hydrodynamics
MrMARTIAN: A Multiresolution Mass Reconstruction Algorithm Combining Free-form and Analytic Components. We present Multi-resolution MAximum-entropy Reconstruction Technique Integrating Analytic Node (MrMARTIAN), a new hybrid strong lensing (SL) modeling algorithm. By incorporating physically motivated analytic nodes into the free-form method MARS, MrMARTIAN enables stable and flexible mass reconstructions while mitigating oversmoothing in the inner mass profile. Its multiresolution framework increases the degrees of freedom in regions with denser SL constraints, thereby enhancing computational efficiency for a fixed number of free parameters. We evaluate the performance of MrMARTIAN using publicly available simulated SL data and find that it consistently outperforms MARS in recovering both mass and magnification. In particular, it delivers significantly more stable reconstructions when multiple images are sparsely distributed. Finally, we apply MrMARTIAN to the galaxy cluster MACS J0416.1─2403, incorporating two analytic nodes centered on the northeastern and southwestern brightest cluster galaxies. Our mass model, constrained by 412 multiple images, achieves an image-plane rms scatter of  ∼0.″11 , the smallest to date for this dataset.

Keywords: Galaxy clusters, Strong gravitational lensing, Dark matter distribution, Dark matter
Discovering High-z BL Lacs Using Swift/UVOT and SARA Observations with the Dropout Technique. Measuring spectroscopic redshifts for BL Lacertae (BL Lac) objects, a class of blazars, is challenging because their optical spectrum lacks, or has weak, emission lines (equivalent width ≤5 Å). In this situation, alternative techniques are necessary for the estimation of distances to these sources. In this paper, we estimate the redshift by the photometric dropout technique for a sample of 64 blazars (59 BL Lacs and 5 blazar candidates of uncertain type). Two telescopes are utilized to observe the sample. The Ultraviolet/Optical Telescope on board Swift observes sources in uvw2, uvm2, uvw1, u, b, and v filters, while the ground-based SARA telescopes at Roque de los Muchachos, La Palma, Spain and Cerro Tololo, Chile observed sources in  g',r,'i',z'  filters. We fit the photometric data with the LePHARE package and report four new high-z (z &gt; 1.3) BL Lacs at  2.03−0.05+0.07 ,  1.84−0.03+0.10 ,  2.04−0.14+0.16 , and  2.93−0.04+0.01  as well as upper limits for 50 sources. This work increased the number of high-z BL Lacs found by this method up to 23. The high-z sources are discussed in the context of the cosmic gamma-ray horizon, blazar sequence, Fermi blazar divide, and masquerading BL Lacs.

Keywords: Blazars, Active galactic nuclei, High energy astrophysics, BL Lacertae objects
The Calibration of Short-wavelength Polycyclic Aromatic Hydrocarbon Emission as Star Formation Rate Indicators with JWST. We use JWST/NIRCam and MIRI imaging acquired by the Feedback in Emerging extrAgalactic Star clusTers (or FEAST) program along with archival Hubble Space Telescope imaging to map ionized gas (Paα, Brα, and Hα) and polycyclic aromatic hydrocarbon (PAH) emission (3.3 and 7.7 μm) across a sample of four nearby galaxies (NGC 5194, 5236, 628, and 4449). These maps are utilized to calibrate the PAH features as star formation rate (SFR) indicators in 40 pc-size regions around massive emerging young star clusters. We find a tight, sublinear (power-law exponent α ∼ 0.8) relation between the PAH luminosities (3.3 and 7.7 μm) and SFR (extinction-corrected Paα) in near-solar-metallicity environments. PAH destruction in more intense ionizing environments and/or variations in the age of our sources may drive the deviation from a linear relation. In the metal-poor environment of NGC 4449 (∼1/3 Z⊙), we see substantial deficits in the PAH feature strengths at fixed SFR and significantly higher scatter in the PAH─SFR relations. We determine that the 3.3/7.7 μm PAH luminosity ratio increases towards lower-metallicity environments. This is interpreted as a result of a shift in the size distribution towards smaller PAHs at lower metallicities, possibly due to inhibited grain growth. Focusing on the regions in NGC 4449, we observe a decreasing 3.3/7.7 μm ratio towards higher SFR, which could indicate that small PAHs are preferentially destroyed relative to larger PAHs in significantly subsolar-metallicity conditions. We estimate that ∼two-thirds of the PAH emission in typical local star-forming galaxies is excited by older stars and unrelated to recent (&lt;10 Myr) star formation.

Keywords: Interstellar dust, Polycyclic aromatic hydrocarbons, Star forming regions, Young star clusters, James Webb Space Telescope, Star formation, Interstellar medium, H II regions, Galaxies
Mirror-mode Structures in Coronal Mass Ejection Sheaths. Coronal mass ejections (CMEs) compress the upstream solar wind as they travel through interplanetary space, forming sheath regions and preceding shocks rich in plasma dynamics. In this study, we identify an abundance of mirror-mode structures within the CME-driven sheath, spanning spatial scales from magnetohydrodynamic to the ion gyroradius. These structures preferentially emerge downstream of quasi-parallel shocks, rather than quasi-perpendicular ones, where elevated ion temperature, anisotropy, and beta provide favorable conditions for their excitation. Unlike planetary magnetosheaths—where mirror modes gradually evolve downstream of bow shocks from wave-like form into nonlinear peak- and hole-like forms—mirror modes in CME-driven sheaths are dominated by magnetic holes, with wave- and peak-like forms rarely present, indicating a rapid instability saturation process. These magnetic holes exhibit larger spatial scales and amplitudes than wave- and peak-like forms and remain stable within the plasma flow, indicating a fully developed state. Multispacecraft observations reveal that they are convected with the sheath plasma flow, suggesting they may constitute the early-stage counterparts of magnetic holes later observed in the solar wind. Our findings highlight the plasma processes triggered by CMEs and help advance understanding of the microphysics of CME-driven disturbances in interplanetary space, including plasma instability excitation, nonlinear evolution, and energy conversion.

Keywords: Space plasmas, Solar wind, Planetary bow shocks, Solar coronal mass ejections, Solar-terrestrial interactions, Planetary magnetospheres
AGN STORM 2. XI. Spectroscopic Reverberation Mapping of the Hot Dust in Mrk 817. The AGN Space Telescope and Optical Reverberation Mapping (STORM) 2 campaign targeted Mrk 817 with intensive multiwavelength monitoring and found its soft X-ray emission to be strongly absorbed. We present results from 157 near-IR spectra with an average cadence of a few days. Whereas the hot dust reverberation signal as tracked by the continuum flux does not have a clear response, we recover a dust reverberation radius of ∼90 lt-days from the blackbody dust temperature light curve. This radius is consistent with previous photometric reverberation mapping results when Mrk 817 was in an unobscured state. The heating/cooling process we observe indicates that the inner limit of the dusty torus is set by a process other than sublimation, rendering it a luminosity-invariant "dusty wall" of a carbonaceous composition. Assuming thermal equilibrium for dust optically thick to the incident radiation, we derive a luminosity of ∼6 × 1044 erg s−1 for the source heating it. This luminosity is similar to that of the obscured spectral energy distribution, assuming a disk with an Eddington accretion rate of  ṁ∼0.2 . Alternatively, the dust is illuminated by an unobscured lower luminosity disk with  ṁ∼0.1 , which permits the UV─optical continuum lags in the high-obscuration state to be dominated by diffuse emission from the broad-line region. Finally, we find hot dust extended on scales ≳ 140─350 pc, associated with the rotating disk of ionised gas we observe in spatially resolved [S III] λ9531 images. Its likely origin is in the compact bulge of the barred spiral host galaxy, where it is heated by a nuclear starburst.

Keywords: Dust physics, Quasars, Dust continuum emission, Active galactic nuclei, Near infrared astronomy
Scylla. V. Constraints on the Spatial and Temporal Distribution of Bursts and the Interaction History of the Magellanic Clouds from Their Resolved Stellar Populations. We measure the star formation histories (SFHs) from the Scylla survey in ∼98,000 pc2 and ∼75,000 pc2 of the Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC), respectively, using deep Hubble Space Telescope imaging (80% complete to &gt; 1 mag below the ancient main-sequence turnoff, ∼25.1 and 26.0 mag in F475W and F814W) from 74 pointings. We group the fields into eight subregions in the SMC and seven in the LMC. We use the birth rate parameter to identify bursts of star formation and measure their properties in each subregion. Our methodology provides a standardized framework for burst identification and reveals both broad and fine burst characteristics. We identify global and local bursts, defined as those occurring in ≥half or &lt;half of a galaxy's subregions, respectively. In the SMC, we find two global (∼5 and 1.5 Gyr ago) and one local burst (∼3 Gyr ago). In the LMC, we find one global burst (∼3 Gyr ago). Comparing these findings with dynamical models of the LMC and SMC orbital histories, we find that when models predict a shared dynamical trigger for bursts across both galaxies, the burst begins earlier in the SMC with a greater enhancement in star formation rate than in the LMC. Finally, using age─metallicity relations and cumulative SFHs, we report that the Wing/Bridge region in the SMC resembles the southwestern LMC both chemically and in stellar mass assembly over the last ∼7 Gyr, possibly due to stellar material stripped from the LMC during their last interaction.

Keywords: Dwarf galaxies, Small Magellanic Cloud, Large Magellanic Cloud, Magellanic Clouds, Star formation, Interacting galaxies
Multifaceted Emission Properties of PSR J2129+4119 Observed with FAST. We present a detailed single-pulse study of the long-period pulsar PSR J2129+4119 using high-sensitivity Five-hundred-meter Aperture Spherical Radio Telescope (FAST) observations. Despite locating well below the traditional death line, the pulsar exhibits sustained and multimodal emission behavior, including nulls, weak pulses, regular emission, and occasional bright pulses. The nulling fraction is measured to be 8.13% ± 0.51%, with null durations typically under four pulse periods. Fluctuation spectral analysis reveals both phase-modulated subpulse drifting and intermittent beatlike modulation. At the same time, polarization profiles show high linear polarization and stable polarization position angle swings consistent with a near-tangential sight line geometry. Quasiperiodic microstructures are detected in 11.54% of regular pulses, with a mean periodicity and width of 4.57 and 4.30 ms, respectively. A well-defined scintillation arc in the secondary spectrum confirms the presence of a localized scattering screen. These results indicate that PSR J2129+4119 remains magnetospherically active and coherently emitting despite its low energy loss rate, offering key insights into pulsar emission physics near the death line.

Keywords: Pulsars, Radio pulsars
General Relativity and the Bulk-flow Puzzle. Bulk peculiar flows are commonplace in the Universe, with many surveys reporting their presence on scales spanning between few hundred and several hundred Mpc. However, the sizes and the speeds of some of these bulk flows are well in excess of those theoretically anticipated, which has made them a potentially serious problem for the ΛCDM model. Having said that, essentially all the available theoretical studies are Newtonian, or quasi-Newtonian, in nature, and both bypass a key feature of peculiar motions, namely the gravitational contribution of the peculiar flux. To begin with, recall that bulk flows are matter in motion and that moving matter means nonzero energy flux. In relativity energy fluxes gravitate, but the gravitational input of the peculiar flux has been largely bypassed. As we will show here, when the flux contribution to the gravitational field is accounted for, linear peculiar velocities grow considerably faster than in the Newtonian/quasi-Newtonian studies. Therefore, general relativity could naturally relax the current ΛCDM limits to accommodate the reported fast bulk flows.

Keywords: Cosmology, Large-scale structure of the universe
Hyperons in Neutron Stars across the Observed Mass Range: Insights from ΛN and ΛΛ Interactions within a Microscopic Framework. We investigate the equation of state (EOS) and macroscopic properties of neutron stars (NSs) and hyperonic stars within the framework of the lowest-order constrained variational (LOCV) method, extended to include interacting Λ hyperons. The nucleon─nucleon interaction is modeled using the AV18 potential supplemented by Urbana three-body forces, while ΛN and ΛΛ interactions are described by phenomenological spin- and parity-dependent potentials calibrated to available hypernuclear data. Cold, charge-neutral, and β-equilibrated matter composed of neutrons, protons, electrons, muons, and Λ hyperons is considered. We compute particle fractions, chemical potentials, the EOS, speed of sound, tidal deformability, and stellar structure by solving the Tolman─Oppenheimer─Volkoff equations, and compare our results with recent NICER and gravitational-wave observations. The inclusion of Λ hyperons leads to EOS softening, reducing the maximum NS mass from 2.34 M⊙ to 2.07 M⊙, while keeping it consistent with the 2 M⊙ mass constraint. At 1.4 M⊙, the model satisfies observational limits on radius and tidal deformability, with the Λ onset occurring below this mass. Comparison with other microscopic and relativistic mean-field models shows that our EOS remains consistent with the allowed pressure─energy density range, while also permitting even canonical-mass NSs of about 1.4 M⊙ to accommodate hyperons. These results suggest that hyperons can appear in NSs across the observed mass range without violating current astrophysical constraints, and that the extended LOCV method provides a consistent, microscopic approach to modeling dense hypernuclear matter.

Keywords: Neutron stars, Neutron star cores
Tidally Driven Inertial Waves Enhance Eccentricity Damping and Spin Evolution in Planets and Stars. Tidal interactions influence the orbital motions of binary star systems and extrasolar planets alike. Tides also affect stellar and planetary rotation rates. We demonstrate that in addition to altering spin synchronization and pseudosynchronization, tidally driven inertial waves in the convective envelopes of low-mass stars and gas-giant planets can enhance tidal eccentricity damping. Analytically, we find that eccentricity damping by inertial waves can be orders of magnitude faster than equilibrium tides, independent of any eddy viscosity prescription. We use simplified numerical experiments to demonstrate this enhancement and to explore the effects of different mixing-length treatments of convective turbulence, as well as a spindown torque from magnetic braking. These calculations demonstrate that tidally driven inertial waves can produce an extended cool core of nearly circular binaries, helping to reconcile a longstanding discrepancy between observed and predicted main-sequence binary circularization. Our calculations additionally suggest that tidally driven inertial waves may leave identifiable signatures in the ratios of the orbital to rotation periods for stellar binaries, including synchronous and subsynchronous rotation periods reminiscent of populations identified in Kepler, TESS, and Gaia data.

Keywords: Hydrodynamics, Stellar astronomy, Exoplanet tides, Tides, Stellar oscillations, Stellar rotation
Galactokinetics. Galactic disks lie at the heart of many astrophysical puzzles. There are sophisticated kinetic theories that describe some aspects of galaxy disk dynamics, but extracting quantitative predictions from those theories has proven very difficult, meaning they have shed little light on observations and simulations of galaxies. Here, we begin to address this issue by developing a tractable theory describing fluctuations and transport in thin galactic disks. Our main conceptual advance is to split potential fluctuations into asymptotic wavelength regimes relative to the orbital guiding radius and epicyclic amplitude (similar to plasma gyrokinetics), and then to treat separately the dynamics in each regime. As an illustration, we apply our results to quasilinear theory, calculating the angular-momentum transport due to a transient spiral. At each stage we verify our formulae with numerical examples. Our approach should simplify many important calculations in galactic disk dynamics. In a follow-up paper, we apply these ideas to the theory of linear spiral structure in stellar disks.

Keywords: Spiral arms, Galaxy dynamics, Disk galaxies