Sazuna/UAT_keywords huggingface dataset:
On the 3D Curvature and Dynamics of the Musca Filament. Filaments are ubiquitous in the interstellar medium, yet their formation and evolution remain the topic of intense debate. In order to obtain a more comprehensive view of the 3D morphology and evolution of the Musca filament, we model the C18O(2-1) emission along the filament crest with several large-scale velocity field structures. This indicates that Musca is well described by a 3D curved cylindrical filament with longitudinal mass inflow to its center unless the filament is a transient structure with a lifetime ≲0.1 Myr. Gravitational longitudinal collapse models of filaments appear unable to explain the observed velocity field. To better understand these kinematics, we further analyze a map of the C18O(2-1) velocity field at the location of SOFIA HAWC+ dust polarization observations that trace the magnetic field in the filament. This unveils an organized magnetic field that is oriented roughly perpendicular to the filament crest. Although the velocity field is also organized, it progressively changes its orientation by more than 90° when laterally crossing the filament crest and thus appears disconnected from the magnetic field in the filament. This strong lateral change of the velocity field over the filament remains unexplained and might be associated with important longitudinal motion that can be associated to the large-scale kinematics along the filament.

Keywords: Interstellar magnetic fields, Interstellar filaments, Interstellar medium, Molecular clouds
Multiple Rings and Asymmetric Structures in the Disk of SR 21. Crescent-like asymmetric dust structures discovered in protoplanetary disks indicate dust aggregations. Thus, researching these structures helps us understand the planet formation process. Here we analyze ALMA data of the protoplanetary disk around the T-Tauri star SR 21, which has asymmetric structures that were detected in previous submillimeter observations. Imaged at ALMA Band 6 (1.3 mm) with a spatial resolution of about 0.″04, the disk is found to consist of two rings and three asymmetric structures, with two of the asymmetric structures being in the same ring. Compared to the Band 6 image, the Band 3 (2.7 mm) image also shows the three asymmetric structures, but with some clumps. The elongated asymmetric structures in the outer ring could be due to the interactions of a growing planet. Based on fitting the Band 3 and Band 6 dust continuum data, two branches of solutions for the maximum dust size in the disk are suggested: one is larger than 1 mm, and the other is smaller than 300 μm. High-resolution continuum observations at longer wavelengths as well as polarization observations can help break the degeneracy. We also suggest that the prominent spiral previously identified in VLT/SPHERE observations south of the star at 0.″25 may be the scattered-light counterpart of the inner arc, and the structure is a dust-trapping vortex in nature. The discovered features in SR 21 make it a good target for studying the evolution of asymmetric structures and planet formation.

Keywords: Protoplanetary disks, Planet formation
Nucleosynthesis of Binary-stripped Stars. The cosmic origin of the elements, the fundamental chemical building blocks of the universe, is still uncertain. Binary interactions play a key role in the evolution of many massive stars, yet their impact on chemical yields is poorly understood. Using the MESA stellar evolution code, we predict the chemical yields ejected in wind mass loss and the supernovae of single and binary-stripped stars. We do this with a large 162-isotope nuclear network at solar metallicity. We find that binary-stripped stars are more effective producers of the elements than single stars, due to their increased mass loss and an increased chance to eject their envelopes during a supernova. This increased production by binaries varies across the periodic table, with F and K being more significantly produced by binary-stripped stars than single stars. We find that the 12C/13C could be used as an indicator of the conservativeness of mass transfer, as 13C is preferentially ejected during mass transfer while 12C is preferentially ejected during wind mass loss. We identify a number of gamma-ray-emitting radioactive isotopes that may be used to help constrain progenitor and explosion models of core-collapse supernovae with next-generation gamma-ray detectors. For single stars we find that 44V and 52Mn are strong probes of the explosion model, while for binary-stripped stars it is 48Cr. Our findings highlight that binary-stripped stars are not equivalent to two single stars and that detailed stellar modeling is needed to predict their final nucleosynthetic yields.

Keywords: Explosive nucleosynthesis, Binary stars, Core-collapse supernovae, Nucleosynthesis, Massive stars
CLEAR: High-ionization [Ne V] λ3426 Emission-line Galaxies at 1.4 &lt; z &lt; 2.3. We analyze a sample of 25 [Ne V] (λ3426) emission-line galaxies at 1.4 &lt; z &lt; 2.3 using Hubble Space Telescope/Wide Field Camera 3 G102 and G141 grism observations from the CANDELS Lyα Emission at Reionization (CLEAR) survey. [Ne V] emission probes extremely energetic photoionization (creation potential of 97.11 eV) and is often attributed to energetic radiation from active galactic nuclei (AGNs), shocks from supernovae, or an otherwise very hard ionizing spectrum from the stellar continuum. In this work, we use [Ne V] in conjunction with other rest-frame UV/optical emission lines ([O II] λ λ3726, 3729, [Ne III] λ3869, Hβ, [O III] λ λ4959, 5007, Hα+[N II] λ λ6548, 6583, [S II] λ λ6716, 6731), deep (2-7 Ms) X-ray observations (from Chandra), and mid-infrared imaging (from Spitzer) to study the origin of this emission and to place constraints on the nature of the ionizing engine. The majority of the [Ne V]-detected galaxies have properties consistent with ionization from AGNs. However, for our [Ne V]-selected sample, the X-ray luminosities are consistent with local (z ≲ 0.1) X-ray-selected Seyferts, but the [Ne V] luminosities are more consistent with those from z ~ 1 X-ray-selected QSOs. The excess [Ne V] emission requires either reduced hard X-rays or a ~0.1 keV excess. We discuss possible origins of the apparent [Ne V] excess, which could be related to the "soft (X-ray) excess" observed in some QSOs and Seyferts and/or be a consequence of a complex/anisotropic geometry for the narrow-line region, combined with absorption from a warm, relativistic wind ejected from the accretion disk. We also consider implications for future studies of extreme high-ionization systems in the epoch of reionization (z ≳ 6) with the James Webb Space Telescope.

Keywords: AGN host galaxies, Photoionization, Quasars, Optical astronomy, Active galaxies, Ultraviolet spectroscopy, Seyfert galaxies, Reionization, High-redshift galaxies
Proposed Lunar Measurements of r-Process Radioisotopes to Distinguish the Origin of Deep-sea <SUP>244</SUP>Pu. 244Pu has recently been discovered in deep-sea deposits spanning the past 10 Myr, a period that includes two 60Fe pulses from nearby supernovae. 244Pu is among the heaviest r-process products, and we consider whether it was created in supernovae, which is disfavored by nucleosynthesis simulations, or in an earlier kilonova event that seeded the nearby interstellar medium with 244Pu that was subsequently swept up by the supernova debris. We discuss how these possibilities can be probed by measuring 244Pu and other r-process radioisotopes such as 129I and 182Hf, both in lunar regolith samples returned to Earth by missions such as Chang'e and Artemis, and in deep-sea deposits.

Keywords: Mass spectrometry, Lunar regolith, R-process, Compact binary stars, Supernovae
CGM<SUP>2</SUP> + CASBaH: The Mass Dependence of H I Lyα-Galaxy Clustering and the Extent of the CGM. We combine data sets from the CGM2 and CASBaH surveys to model a transition point, R cross, between circumgalactic and intergalactic media (CGM and IGM, respectively). In total, our data consist of 7244 galaxies at z &lt; 0.5 with precisely measured spectroscopic redshifts, all having impact parameters of 0.01-20 comoving Mpc from 28 QSO sightlines with high-resolution UV spectra that cover H I Lyα. Our best-fitting model is a two-component model that combines a 3D absorber-galaxy cross-correlation function with a simple Gaussian profile at inner radii to represent the CGM. By design, this model gives rise to a determination of R cross as a function of galaxy stellar mass, which can be interpreted as the boundary between the CGM and IGM. For galaxies with 108 ≤ M ⋆/M ☉ ≤ 1010.5, we find that R cross(M ⋆) ≈ 2.0 ± 0.6R vir. Additionally, we find excellent agreement between R cross(M ⋆) and the theoretically determined splashback radius for galaxies in this mass range. Overall, our results favor models of galaxy evolution at z &lt; 0.5 that distribute T ≈ 104K gas to distances beyond the virial radius.

Keywords: Astronomical models, Astronomy data modeling, Bayesian statistics, Quasar absorption line spectroscopy, Surveys, Galactic and extragalactic astronomy, Galaxy photometry, Galaxy evolution, Circumgalactic medium, Galaxy spectroscopy, Galaxies
LensWatch. I. Resolved HST Observations and Constraints on the Strongly Lensed Type Ia Supernova 2022qmx ("SN Zwicky"). Supernovae (SNe) that have been multiply imaged by gravitational lensing are rare and powerful probes for cosmology. Each detection is an opportunity to develop the critical tools and methodologies needed as the sample of lensed SNe increases by orders of magnitude with the upcoming Vera C. Rubin Observatory and Nancy Grace Roman Space Telescope. The latest such discovery is of the quadruply imaged Type Ia SN 2022qmx (aka, "SN Zwicky") at z = 0.3544. SN Zwicky was discovered by the Zwicky Transient Facility in spatially unresolved data. Here we present follow-up Hubble Space Telescope observations of SN Zwicky, the first from the multicycle "LensWatch (www.lenswatch.org)" program. We measure photometry for each of the four images of SN Zwicky, which are resolved in three WFC3/UVIS filters (F475W, F625W, and F814W) but unresolved with WFC3/IR F160W, and present an analysis of the lensing system using a variety of independent lens modeling methods. We find consistency between lens-model-predicted time delays (≲1 day), and delays estimated with the single epoch of Hubble Space Telescope colors (≲3.5 days), including the uncertainty from chromatic microlensing (~1-1.5 days). Our lens models converge to an Einstein radius of ${\theta }_{{\rm{E}}}=({0.168}_{-0.005}^{+0.009})^{\prime\prime} $ , the smallest yet seen in a lensed SN system. The "standard candle" nature of SN Zwicky provides magnification estimates independent of the lens modeling that are brighter than predicted by $\sim {1.7}_{-0.6}^{+0.8}$ mag and $\sim {0.9}_{-0.6}^{+0.8}$ mag for two of the four images, suggesting significant microlensing and/or additional substructure beyond the flexibility of our image-position mass models.

Keywords: Strong gravitational lensing, Type Ia supernovae
A Detailed View of Low-frequency Quasi-periodic Oscillation in the Broadband 0.2-200 keV with Insight-HXMT and NICER. We report the X-ray timing results of the black hole candidate MAXI J1820+070 during its 2018 outburst using the Hard X-ray Modulation Telescope (Insight-HXMT) and Neutron Star Interior Composition Explorer Mission (NICER) observations. Low-frequency quasi-periodic oscillations (LFQPOs) are detected in the low/hard state and the hard intermediate state, which lasted for ~90 days. Thanks to the large effective area of Insight-HXMT at high energies and NICER at low energies, we are able to present the energy dependence of the LFQPO characteristics and phase lags from 0.2 to 200 keV, which has never been explored by previous missions. We find that the centroid frequency of the LFQPOs does not change significantly with energy, while the full width at half maximum and fractional rms show a complex evolution with energy. The LFQPO phase lags at high energies and low energies show consistent energy-dependence relations taking the ~2 keV as reference. Our results suggest that the LFQPOs from high energy come from the LT precession of the relativistic jet, while the low-energy radiation is mainly from the perpendicular innermost regions of the accretion disk.

Keywords: Black hole physics
Hydrogen-triggered X-Ray Bursts from SAX J1808.4-3658? The Onset of Nuclear Burning. We present a study of weak, thermonuclear X-ray bursts from the accreting millisecond X-ray pulsar SAX J1808.4-3658. We focus on a burst observed with the Neutron Star Interior Composition Explorer on 2019 August 9, and describe a similar burst observed with the Rossi X-ray Timing Explorer in 2005 June. These bursts occurred soon after outburst onset, 2.9 and 1.1 days, after the first indications of fresh accretion. We measure peak burst bolometric fluxes of 6.98 ± 0.50 × 10-9 and 1.54 ± 0.10 × 10-8 erg cm-2 s-1, respectively, which are factors of ≈30 and 15 less than the peak flux of the brightest, helium-powered bursts observed from this source. From spectral modeling we estimate the accretion rates and accreted columns at the time of each burst. For the 2019 burst we estimate an accretion rate of $\dot{M}\approx 1.4\mbox{--}1.6\times {10}^{-10}$ M ⊙ yr-1, and a column in the range 3.9-5.1 × 107 g cm-2. For the 2005 event the accretion rate was similar, but the accreted column was half of that estimated for the 2019 burst. The low accretion rates, modest columns, and evidence for a cool neutron star in quiescence, suggest these bursts are triggered by thermally unstable CNO cycle hydrogen burning. The post-burst flux level in the 2019 event appears offset from the pre-burst level by an amount consistent with quasi-stable hydrogen burning due to the temperature-insensitive, hot-CNO cycle, further suggesting hydrogen burning as the primary fuel source. This provides strong observational evidence for hydrogen-triggered bursts. We discuss our results in the context of previous theoretical modeling.

Keywords: Neutron stars, X-ray binary stars, X-ray sources, X-ray bursts
The Diffuse Ionized Gas Halo of the Large Magellanic Cloud. The Large Magellanic Cloud (LMC) has an extensive Hα emission halo that traces an extended, warm ionized component of its interstellar medium. Using the Wisconsin Hα Mapper telescope, we present the first kinematic Hα survey of an extensive region around the LMC, from (ℓ, b) = (264.°5, - 45.°5) to (295.°5, - 19.°5), covering +150 ≤ v LSR ≤ + 390 km s-1. We find that ionized hydrogen exists throughout the galaxy and extends several degrees beyond detected neutral hydrogen emission $(\mathrm{log}\left({N}_{{\rm{H}}\,{\rm\small{I}}/{\mathrm{cm}}^{-2}}\right)\approx 18.3)$ as traced by 21 cm in current surveys. Using the column density structure of the neutral gas and stellar line-of-sight depths as a guide, we estimate the upper limit mass of the ionized component of the LMC to be roughly M ionized ≈ (0.6-1.8) × 109 M ☉, which is comparable to the total neutral atomic gas mass in the same region (M neutral ≈ 0.76-0.85 × 109 M ☉). Considering only the atomic phases, we find M ionized/M ionized+neutral, to be 46%-68% throughout the LMC and its extended halo. Additionally, we find an ionized gas cloud that extends off of the LMC at (ℓ, b) ≈ (285°, - 28°) into a region previously identified as the Leading Arm complex. This gas is moving at a similar line-of-sight velocity as the LMC and has M ionized/M ionized+neutral = 13%-51%. This study, combined with previous studies of the SMC and extended structures of the Magellanic Clouds, continues to suggest that warm, ionized gas is as massive and dynamically important as the neutral gas in the Magellanic System.

Keywords: Local Group, Dwarf galaxies, Large Magellanic Cloud, Warm ionized medium, Galaxy kinematics, Interstellar medium
A Flat-spectrum Radio Transient at 122 Mpc Consistent with an Emerging Pulsar Wind Nebula. We report the discovery and follow-up observations of VT 1137-0337, an unusual radio transient found in our systematic search for extragalactic explosions in the Very Large Array Sky Survey. It is located in the brightest region of a dwarf starburst galaxy at a luminosity distance of 121.6 Mpc. Its 3 GHz luminosity is comparable to luminous radio supernovae associated with dense circumstellar interaction and relativistic outflows. However, its broadband radio spectrum-proportional to ν -0.35 over a range of ≳10× in frequency and fading at a rate of 5% yr-1-cannot be directly explained by the shock of a stellar explosion. Jets launched by various classes of accreting black holes also struggle to account for VT 1137-0337's combination of observational properties. Instead, we propose that VT 1137-0337 is a decades-old pulsar wind nebula that has recently emerged from within the free-free opacity of its surrounding supernova ejecta. If the nebula is powered by spin-down, the central neutron star should have a surface dipole field of ~1013-1014 G and a present-day spin period of ~10-100 ms. Alternatively, the nebula may be powered by the release of magnetic energy from a magnetar. Magnetar nebulae have been proposed to explain the persistent radio sources associated with the repeating fast radio bursts FRB 121102 and FRB 190520B. These FRB persistent sources have not previously been observed as transients but do bear a striking resemblance to VT 1137-0337 in their radio luminosity, spectral index, and host galaxy properties.

Keywords: Neutron stars, Transient sources, Radio bursts, Time domain astronomy, Pulsar wind nebulae, Magnetars, Spectral index, Radio astronomy, Radio transient sources
3D Radiation Hydrodynamic Simulations of Gravitational Instability in AGN Accretion Disks: Effects of Radiation Pressure. We perform 3D radiation hydrodynamic local shearing-box simulations to study the outcome of gravitational instability (GI) in optically thick active galactic nuclei (AGNs) accretion disks. GI develops when the Toomre parameter Q  T  ≲ 1, and may lead to turbulent heating that balances radiative cooling. However, when radiative cooling is too efficient, the disk may undergo runaway gravitational fragmentation. In the fully gas-pressure-dominated case, we confirm the classical result that such a thermal balance holds when the Shakura-Sunyaev viscosity parameter (α) due to the gravitationally driven turbulence is ≲0.2, corresponding to dimensionless cooling times Ωt cool ≳ 5. As the fraction of support by radiation pressure increases, the disk becomes more prone to fragmentation, with a reduced (increased) critical value of α (Ωt cool). The effect is already significant when the radiation pressure exceeds 10% of the gas pressure, while fully radiation-pressure-dominated disks fragment at t cool ≲ 50 Ω-1. The latter translates to a maximum turbulence level α ≲ 0.02, comparable to that generated by magnetorotational instability. Our results suggest that gravitationally unstable (Q  T  ~ 1) outer regions of AGN disks with significant radiation pressure (likely for high/near-Eddington accretion rates) should always fragment into stars, and perhaps black holes.

Keywords: Accretion, Supermassive black holes, Gravitational instability, Galaxy accretion disks, Star formation
Understanding the Relationship between Solar Coronal Abundances and F10.7 cm Radio Emission. Sun-as-a-star coronal plasma composition, derived from full-Sun spectra, and the F10.7 radio flux (2.8 GHz) have been shown to be highly correlated (r = 0.88) during solar cycle 24. However, this correlation becomes nonlinear during increased solar magnetic activity. Here we use cotemporal, high spatial resolution, multiwavelength images of the Sun to investigate the underlying causes of the nonlinearity between coronal composition (FIP bias) and F10.7 solar index correlation. Using the Karl G. Jansky Very Large Array, Hinode/EIS (EUV Imaging Spectrometer), and the Solar Dynamics Observatory, we observed a small active region, AR 12759, throughout the solar atmosphere from the photosphere to the corona. The results of this study show that the magnetic field strength (flux density) in active regions plays an important role in the variability of coronal abundances, and it is likely the main contributing factor to this nonlinearity during increased solar activity. Coronal abundances above cool sunspots are lower than in dispersed magnetic plage regions. Strong magnetic concentrations are associated with stronger F10.7 cm gyroresonance emission. Considering that as the solar cycle moves from minimum to maximum, the sizes of sunspots and their field strength increase with the gyroresonance component, the distinctly different tendencies of radio emission and coronal abundances in the vicinity of sunspots is the likely cause of saturation of Sun-as-a-star coronal abundances during solar maximum, while the F10.7 index remains well correlated with the sunspot number and other magnetic field proxies.

Keywords: Solar abundances, Solar magnetic fields, Solar radio emission, Solar corona
Uranium Abundances and Ages of r-process Enhanced Stars with Novel U II Lines. The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an avenue to determining the ages of these stars independent from stellar-evolution models. The uranium abundance, which can be determined for metal-poor r-process enhanced (RPE) stars, has been known to constitute one of the most robust chronometers known. So far, U abundance determination has used a single U II line at λ3859 Å. Consequently, U abundance has been reliably determined for only five RPE stars. Here, we present the first homogeneous U abundance analysis of four RPE stars using two novel U II lines at λ4050 Å and λ4090 Å, in addition to the canonical λ3859 Å line. We find that the U II lines at λ4050 Å and λ4090 Å are reliable and render U abundances in agreement with the λ3859 U abundance, for all of the stars. We, thus, determine revised U abundances for RPE stars, 2MASS J09544277+5246414, RAVE J203843.2-002333, HE 1523-0901, and CS 31082-001, using multiple U II lines. We also provide nucleocosmochronometric ages of these stars based on the newly derived U, Th, and Eu abundances. The results of this study open up a new avenue to reliably and homogeneously determine U abundance for a significantly larger number of RPE stars. This will, in turn, enable robust constraints on the nucleocosmochronometric ages of RPE stars, which can be applied to understand the chemical enrichment and evolution in the early universe, especially of r-process elements. *Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Additionally, this work is based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program IDs 275.D-5028(A), 077.D-0453(A), and 165.N-0276(A). This paper also includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Stellar abundances, R-process, Population II stars, Cosmochronology, Stellar atmospheres