Sazuna/UAT_keywords huggingface dataset:
Fractal Aggregate Aerosols in the Virga Cloud Code. II. Exploring the Effects of Key Cloud Parameters in Warm Neptune, Hot Jupiter and Brown Dwarf Atmospheres. Aerosols and clouds are expected to be ubiquitous in exoplanet and brown dwarf atmospheres, where they can have a significant impact on transmission and emission spectra. The cloud code Virga is capable of quickly modeling cloud particle sizes as a function of altitude, and has recently been updated to include functionality for aggregates (ranging from very fluffy chains to compact fractals). We analyze the effect that these aggregates have on transmission spectra for typical warm Neptune and hot Jupiter environments, as well as their effect on emission spectra for an L-type brown dwarf, over the wavelength range 0.3─15 μm. We find significant, measurable differences in spectra when particle shape is changed (particularly the shortest wavelengths, where particle morphology strongly affects the scattering slope). We provide some intuitive rules for how nonabsorbing aggregates impact spectra: When particle sizes are small compared to the wavelength of light, the most elongated and chain-like particles have the highest opacities; when particles are large, the inverse is true (the most compact shapes have the highest opacities). We present an explanation for these effects in terms of the dynamics of how the particles form and move through the atmosphere, as well as in terms of fundamental optics theory. Given the significant impact that particle shape can have on spectra, we strongly encourage the community to include shape as a free parameter in future case studies, atmospheric models, and retrievals.

Keywords: Exoplanet atmospheric composition , Exoplanets, Exoplanet atmospheric dynamics, Exoplanet atmospheres, Exoplanet atmospheric structure
Research into the Magnetic Configuration of Eruptive Filaments with a High-class Flare. Filament eruptions are the source of coronal mass ejections, and these phenomena are likely to pose a serious threat to space weather safety. The magnetic structures that carry the filament material are considered the core structures of the eruption, and they may drive the eruption through magnetohydrodynamic instabilities and magnetic reconnection. In this study, we successfully performed three-dimensional magnetic field reconstruction of the corona for 16 filament eruption events associated with strong flares (at least M-class) between 2011 and 2022, and all the magnetic structures can be strictly matched with the EUV observational morphology of the filaments. We further calculated and analyzed the parameters used to characterize the MHD instabilities and magnetic reconnection of the magnetic structures. The kink instability parameter indicated that almost all events exhibited twisted features of a magnetic flux rope before the eruption, while the torus instability parameter was generally low. On the other hand, in the map of the Q-value distribution, which describe whether the connectivity of the magnetic structure is prone to change, we found that more than 60% of the magnetic ropes exhibited obvious reconnection features. Combining this with evolutionary diagrams of the positions of the filament material, we suggest that, in the environment of strong flares, magnetic reconnection plays a more important role in triggering filament eruption events than torus instability.

Keywords: Solar flares, Solar filaments, Solar filament eruptions, Solar magnetic reconnection
The ALPINE-CRISTAL-JWST Survey: Stellar and Nebular Dust Attenuation of Main-sequence Galaxies at z ∼ 4─6. Characterizing dust attenuation is crucial for revealing the intrinsic physical properties of galaxies. We present an analysis of dust attenuation in 18 spectroscopically confirmed star-forming main-sequence galaxies at z = 4.4−5.7 observed with JWST/NIRSpec IFU and NIRCam, selected from the ALPINE and CRISTAL ALMA large programs. We fit the emission-line fluxes from NIRSpec and the broadband photometry from NIRCam with PROSPECTOR, using both spatially integrated emission and ∼0.6 kpc pixel-by-pixel measurements. We derive the stellar-to-nebular dust attenuation ratio (f = E(B − V)star/E(B − V)neb) from the SED fits and the Balmer decrement with Hα and Hβ. Although individual galaxies show large scatter, the best-fit value is  f=0.51−0.03+0.04 , slightly higher than that measured for local starburst galaxies. We find weak correlations of f with galaxy properties, increasing with higher specific star formation rates, younger stellar ages, and more recent star formation. For the range of E(B − V)star = 0.009−0.15 mag for in our sample, assuming f = 1 (often adopted in high-redshift studies) instead of f = 0.51 leads to the underestimation of line luminosities and ionizing photon production efficiency ξion by ∼3%−36% and ∼4%−46%, respectively. Finally, total stellar masses estimated from spatially integrated SED fits with delayed-τ star formation histories are systematically smaller than the sums of pixel-by-pixel SED fits by a median of ∼0.26 dex, likely because the integrated fits are biased toward luminous young stellar populations.

Keywords: Surveys, High-redshift galaxies, Galaxy evolution, Interstellar dust extinction
Deep Chandra Observations of the z = 1.16 Relaxed, Cool-core Galaxy Cluster SPT-CL J2215-3537. Galaxy clusters serve as a unique and valuable laboratory for probing cosmological models and understanding astrophysics at the high-mass limit of structure formation. Clusters that are dynamically relaxed are especially useful targets of study because of their morphological and dynamical simplicity. However, at redshifts z &gt; 1, very few such clusters have been identified. We present results from new Chandra observations of the cluster SPT-CL J2215-3537 (hereafter SPT J2215), at z = 1.16, the second-most distant, relaxed, cool-core cluster identified to date. We place constraints on the cluster's total mass profile and investigate its thermodynamic profiles, scaling relations (gas mass, average temperature, and X-ray luminosity), and metal enrichment, resolving the cool core and providing essential context for the massive starburst seen in its central galaxy. We contextualize the thermodynamic and cosmological properties of the cluster within a sample of well-studied, lower-redshift relaxed systems. In this way, SPT J2215 serves as a powerful high-redshift benchmark for understanding the formation of cool cores and the evolution of massive clusters of galaxies.

Keywords: Cosmology, Galaxy clusters, X-ray astronomy, Cool cores
Surrogate-accelerated Bayesian Inversion for Exoplanet Interior Characterization. Characterizing the interior structure of exoplanets is an inverse problem often solved using Bayesian inference, but this approach is hampered by the high computational cost of planetary structure models. To overcome this barrier, we present a robust framework that accelerates inference by replacing the computationally expensive physics-based forward model with a fast polynomial chaos-Kriging (PCK) surrogate directly within a Markov Chain Monte Carlo (MCMC) sampling loop. We rigorously validate our approach using a suite of tests, including a direct comparison against a benchmark MCMC inference using the full forward model, and a large-scale coverage study with 1000 synthetic test cases to demonstrate the statistical reliability of our inferred credible intervals. Our surrogate-assisted framework achieves a computational speedup of over 2 orders of magnitude (factor of ∼320), reducing single-CPU inference times from days to minutes. This efficiency is achieved with a surrogate that requires only a few hundred forward model evaluations for training for a single planet. This data efficiency provides significant flexibility for model developments and a clear advantage over common machine learning approaches, which typically demand vast training sets (&gt;106 model runs) and intensive precomputation. The PCK surrogate maintains high fidelity, with R2 &gt; 0.99 for most scenarios, and root-mean-square errors typically an order of magnitude smaller than observational uncertainties. This efficiency enables large-scale population studies while preserving statistical robustness, which is computationally impractical with traditional methods.

Keywords: Exoplanet atmospheric composition , Atmospheric structure, Structure determination, Planetary interior, Exoplanet atmospheres, Exoplanet atmospheric structure
How Is Cold Gas Loaded into Galactic Nuclear Outflows?. The origin of the multiphase gas within the Fermi/eROSITA bubbles is crucial for understanding Galactic center (GC) feedback. We use HI4PI data to investigate the kinematics and physical properties of high-velocity clouds (HVCs) toward the GC region (l = +25° to −10°). Our results reveal that the HVCs exhibit a distinct asymmetric distribution, closely associated with bar-driven tilted dust lanes and distorted overshooting streams. We propose that powerful nuclear outflows interact with these gas-rich, off-plane structures, striping and entraining cold gas from the outer Galactic regions (RGC ∼ 0.5─1.7 kpc) rather than solely from the central molecular zone (CMZ; RGC ≲ 0.3 kpc). In this scenario, as the Galactic bar drives gas inflows along the dust lanes, nuclear outflows simultaneously break through the CMZ, sweeping up and ablating cold gas from the boundary layer of these preexisting structures. This process naturally accounts for the observed high turbulence, complex spectral signatures, and anomalous spatial-kinematic gas patterns, as well as multiwavelength asymmetries of the bubbles. The HVCs are accelerated to about 230─340 km s−1 over a dynamical time of ∼3─6 Myr. When the multiphase, inhomogeneous composition of the gas is included, the estimated gas outflow rate in on the order of ∼1 M⊙ yr−1. This value is comparable to the bar-driven inflow rate, indicating a tightly coupled gas cycle in the inner Galaxy. Our research highlights the critical role of bar-driven gas dynamics and nuclear feedback in the secular evolution of the Milky Way, offering a valuable paradigm for investigating the gas outflow─inflow cycle in external galaxies.

Keywords: Galactic winds, High-velocity clouds, Molecular clouds, Interstellar medium, Milky Way Galaxy
Stellar Rotation in the First 6 Myr: Rotational Velocities and Radii Estimates of T Tauri Stars in IC 5070 and IC 348. We have acquired high-resolution optical spectroscopy for a sample of T Tauri stars (TTSs) in open clusters using Hydra on the WIYN 3.5 m telescope, and present projected rotational velocities (v sin i values) for 54 stars in IC 5070 and 99 stars in IC 348. We combine these with published values for stellar temperature, luminosity, rotation period, circumstellar disk status, and binarity; we are predominantly interested in how the last two factors may affect the rotation speeds of the stars. We find evidence to support theories that interaction with circumstellar disks may slow the rotation of TTSs compared to class III stars in both clusters. We also identify a higher fraction of slow-rotating class III stars in IC 348 compared to other clusters; we suggest that some fraction of these may be stars that recently lost their disks. We find that a higher fraction of binary stars are rapid rotators compared to single stars, although not to a statistically significant degree. We also combine our v sin i measurements with rotation periods to estimate projected stellar radii, which we compare to predictions from stellar evolution models using a maximum-likelihood method. We continue to show that models with increasing starspot coverage reduce radius inflation and align better with published age estimates than models without starspots.

Keywords: Starspots, Fundamental parameters of stars, Stellar radii, T Tauri stars, Pre-main sequence stars, Stellar rotation, Stellar evolution
Possible Evidence for Extended X-Ray Emission Surrounding PSR B0656+14 with eROSITA. Extended very-high-energy γ-ray emission from middle-aged pulsars as revealed recently by several ground-based γ-ray experiments has strong implication on the transport of high-energy particles in the interstellar medium surrounding those pulsars. The γ-ray emission is widely believed to be produced by high-energy electrons and positrons accelerated by the pulsar wind nebulae when scattering off the interstellar radiation field via the inverse Compton process. Consequently, multiwavelength counterparts of the γ-ray halos are expected to be present, which have not yet been detected. In this work we report the possible detection of extended X-ray emission from a ∼0 .° 2 radius region around PSR B0656+14 with eROSITA. In spite of there being uncertainties of the on-orbit point-spread function of the pointing mode, the radial profile of PSR B0656+14 is found to be broader than that of a star at similar observational conditions, indicating that emission is possibly from the expected extended halo around the pulsar. The spectrum of the emission can be described by a power-law function with an index of ∼3.7. Its surface brightness declines with radius faster than the prediction of the particle diffusion and synchrotron radiation in a uniform magnetic field, suggesting the existence of a radial gradient of the magnetic field strength as ∼r−1. The magnetic field strength in the X-ray-emitting region is constrained to be 4─10 μG.

Keywords: High energy astrophysics, Pulsars, Non-thermal radiation sources, Gamma-ray observatories, Cosmic rays
The Effect of the Fast-flavor Instability on Core-collapse Supernova Models. II. Quasi-equipartition and the Impact of Various Angular Reconstruction Methods. In this work, we explore the effects of fast-flavor conversion (FFC) in one-dimensional (1D) and two-dimensional (2D) core-collapse supernova (CCSN) simulations. In addition, we investigate the impact of various angular reconstruction methods and compare the "3-species" and "4-species" neutrino transport schemes. We find that the FFC effects are insensitive to the different methods tested and that the FFC alters supernova hydrodynamics in only minor ways. We also present a "quasi-equipartition" approximation that can be used to estimate the FFC-altered neutrino properties by postprocessing the neutrino signals extracted from no-oscillation CCSN simulations. The relative errors in neutrino number and energy luminosities of this phenomenological method are less than 2% for 1D models and less than 10% for 2D models. This method provides a simple way to include the effects of FFC on neutrino signals without implementing a complex and expensive FFC scheme or redoing simulations.

Keywords: Neutrino oscillations, Supernova neutrinos, Core-collapse supernovae
Discovery of a Luminosity-dependent Continuum Lag in NGC 4151 from Photometric and Spectroscopic Continuum Reverberation Mapping. Accretion onto supermassive black holes (SMBHs) powers active galactic nuclei (AGNs) and drives feedback that shapes galaxy evolution. Constraining AGN accretion disk structure is therefore essential for understanding black hole growth and feedback processes. However, direct constraints on disk size remain rare—particularly from long-term, multiseason spectroscopic reverberation mapping (RM), which is critical for isolating the intrinsic disk response from the broad-line region (BLR). We present results from an intensive multiwavelength RM campaign of NGC 4151 during its brightest state in nearly two decades. This represents the third high-cadence monitoring over the past decade, capturing accretion states spanning the transitional regime between thin and thick disks, making NGC 4151 the only AGN with continuum RM observations across such a wide range in accretion states. Combining spectroscopy from the Lijiang 2.4 m telescope with coordinated Swift UV/X-ray monitoring, we measure interband continuum lags from UV to optical. The wavelength-dependent lags follow a tight τ ∝ λ4/3 relation, consistent with reprocessing in a thin disk, but exceed theoretical predictions by a factor of 6.6. Our lag spectrum reveals clear excesses near the Balmer and possibly Paschen jumps, confirming diffuse continuum (DC) contamination from the BLR. By comparing the three campaigns, we discover a nonmonotonic lag─luminosity trend (&gt;3σ), which cannot be explained by DC emission alone. We propose that the lags reflect combined disk and BLR contributions, and present the first evidence that the DC component follows an intrinsic Baldwin effect. These results offer new insights into SMBH mass measurements and theoretical models of AGN inner structure.

Keywords: Accretion, Supermassive black holes, Reverberation mapping, Active galactic nuclei
Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not. In this work, we investigate the dynamical survival of short-period inner planets during the high-eccentricity tidal migration of companion exterior giant planets. Using a combination of analytic arguments and N-body simulations, including equilibrium tides and general relativistic precession, we find the boundary in parameter space where an inner companion can remain dynamically stable. We find that survival requires a periastron separation exceeding roughly 14 mutual Hill radii at closest approach. Below this threshold, secular eccentricity exchange, orbit crossing, and/or tidal evolution can lead to the destruction of the inner planet. We apply our methodology to the current exoplanet sample and find that none of the known systems containing a short-period giant and an inner companion could have assembled via high-eccentricity tidal migration. However, warm Jupiters with larger periastron distances (qout ∼ 0.05─0.08 au, corresponding to final observed semimajor axis values aout ∼ 0.10─0.16 au) can allow the survival of short-period inner planets while potentially also circularizing on ≲1 Gyr timescales. Our results provide a framework for distinguishing disk migration from tidal migration in observed multi-planet systems containing close-in gas giants.

Keywords: Exoplanet dynamics, Exoplanet migration, Exoplanet systems, Hot Jupiters
The Local Group L-band Survey: Probing Cold Atomic Gas in IC 10 with Neutral Hydrogen Absorption. We present the first localized detections of the cold neutral medium (CNM) in IC 10, offering a rare view of dense atomic gas in a low-metallicity (Z/Z⊙ ∼ 0.27) dwarf galaxy. As a low-metallicity starburst, IC 10's interstellar medium conditions could reflect small scale physics conditions that mirror those of early galaxies, providing a unique window into the heating and cooling processes that shaped the interstellar medium in early-Universe environments. Leveraging the high angular (&lt;5″ ∼ 15 pc) and spectral (0.4 km s−1) resolution of the Local Group L-band Survey, we searched for H I absorption against nine continuum radio sources and detected absorption along three sightlines corresponding to internal radio emission sources within IC 10. Using Gaussian decomposition and radiative transfer, we characterize the CNM, deriving spin temperatures of ∼30─55 K, column densities of (0.6─3.0) × 1021 cm−2, cold H I fractions of ∼21%─37%, and line widths of ∼5.6─13.6 km s−1. For each individual detection of H I absorption, we find corresponding molecular emission from 12CO (J = 1─0), HCO+ (J = 1─0), and HCN (J = 1─0) at similar velocities and with comparable line widths, indicating a well-mixed cold atomic and molecular medium. In IC 10, the CNM shows a clear kinematic connection to the high-density ISM, implying a stronger dynamical coupling with molecular gas than in the Milky Way, in line with expectations for low-metallicity environments. At the ∼15 pc scales probed by slightly extended H II regions in IC 10, unresolved CNM clouds likely contribute to line blending, so the observed broad H I line widths may partly reflect spatial and kinematic averaging.

Keywords: Interstellar absorption, Dwarf galaxies, Interstellar medium
The Hidden Story of Chemical Evolution in Local Star-forming Nuclear Rings. A Very Large Telescope/MUSE population synthesis study of metallicities in the nuclear star-forming rings of four disk galaxies (NGC 613, NGC 1097, NGC 3351, NGC 7552) is presented. Disentangling the spectral contributions of young and old stellar populations, we find a large spread of ages and metallicities of the old stars in the nuclear rings. This indicates a persistent infall of metal-poor gas and ongoing episodic star formation over many Gyr. The young stars have metallicities a factor two to three higher than solar in all galaxies except NGC 3351, where the range is from half to twice solar. Previously reported detections of extremely metal-poor regions at young stellar age on the rings of these four galaxies are a methodological artifact of the average over all stars, young and old. In addition, it is important to include contributions of very young stars (&lt;6 Myr) in this environment. For each of the four galaxies, the extinction maps generated through our population synthesis analysis provide support for the infall scenario. They reveal dust lanes along the leading edges of the stellar bars, indicating the flow of interstellar material toward the circumnuclear zone. Prominent stellar clusters show little extinction, most likely because of the onset of stellar winds. Inside and on the nuclear rings, regions that are largely free of extinction are detected.

Keywords: Galaxy chemical evolution, Stellar populations, Galaxy circumnuclear disk, Barred spiral galaxies, Metallicity
JWST Observations of SN 2024ggi. II. NIRSpec Spectroscopy and CO Modeling at +285─385 Days past the Explosion. We present James Webb Space Telescope (JWST) Near-Infrared Spectrograph observations of SN 2024ggi, spanning wavelengths of 1.7─5.5 μm at +285.51 and +385.27 days postexplosion. These nebular spectra are dominated by asymmetric emission lines from atomic species including H, Ca, Ar, C, Mg, Ni, Co, and Fe, indicative of an aspherical explosion. The other strong features are molecular CO vibrational bands from the fundamental and first overtone. We introduce a novel, data-driven approach using non─local thermodynamic equilibrium three-dimensional (3D) radiative transfer simulations to model the CO emission with high fidelity. This method enables us to constrain the 3D CO distribution and its radial temperature structure. CO formation is found to occur prior to day +285, with subsequent evolution characterized by progressive evaporation. The CO mass decreases from approximately 8.7 to 1.3 ×10−3M⊙, while the average temperature drops from ≍2900 to ≍2500 K. Concurrently, the CO distribution transitions from nearly homogeneous to highly clumped (density contrast increasing from fc ≍ 1.2 to 2). The minimum velocity of the CO-emitting region remains nearly constant (v1 ≍ 1200 to 1100 km s−1), significantly above the receding photosphere velocity (vph ≍ 500 km s−1), suggesting the photosphere resides within Si-rich layers. However, the temperature profile indicates that only a narrow zone reaches the conditions necessary for SiO formation. Due to a lack of observational constraints, SiO clumping is not modeled, and thus, synthetic SiO profiles for mass estimates are not highlighted. We discuss the implications of these findings for dust formation processes in SN 2024ggi.

Keywords: Type II supernovae