Sazuna/UAT_keywords huggingface dataset:
Water Ice in the Edge-on Orion Silhouette Disk 114–426 from JWST NIRCam Images. We examine images of the protoplanetary disk 114–426 with JWST/NIRCam in 12 bands. This large disk is oriented edge on with a dark midplane flanked by lobes of scattered light. The outer edges of the midplane are seen in silhouette against the Orion Nebula, providing a unique opportunity to study planet-forming material in absorption. We discover a dip in the scattered light of the disk at 3 μm—compelling evidence for the presence of water ice. The 3 μm dip is also seen in the silhouette of the disk, where we quantify the ice abundance with models of pure absorption and avoid the complications of disk scattering effects. We find grain ice-to-refractory mass ratios of up to ~0.2, maximum grain sizes of 0.25–5 μm, and a total dust plus ice mass of 0.46 M⊕ in the silhouette region. We also discover excess absorption in the NIRCam bands that include the Paα line, suggesting there may be excited atomic hydrogen in the disk. Examining the morphology of the scattered light lobes reveals that they are laterally offset from each other and exhibit a brightness asymmetry that flips with wavelength—both evidence for a tilted inner disk in this system.

Keywords: Circumstellar dust, Protoplanetary disks, Astrochemistry
The Origins of Lithium Enhancement in Polluted White Dwarfs. The bulk abundances of exoplanetesimals can be measured when they are accreted by white dwarfs. Recently, lithium from the accretion of exoplanetesimals was detected in relatively high levels in multiple white dwarfs. There are presently three proposed hypotheses to explain the detection of excess lithium in white dwarf photospheres: Big Bang and Galactic nucleosynthesis, continental crust, and an exomoon formed from spalled ring material. We present new observations of three previously known lithium-polluted white dwarfs (WD J1824+1213, WD J2317+1830, and LHS 2534), and one with metal pollution without lithium (SDSS J1636+1619). We also present atmospheric model fits to these white dwarfs. We then evaluate the abundances of these white dwarfs and two additional lithium-polluted white dwarfs that were previously fit using the same atmospheric models (WD J1644-0449 and SDSS J1330+6435) in the context of the three extant hypotheses for explaining lithium excesses in polluted white dwarfs. We find Big Bang and Galactic nucleosynthesis to be the most plausible explanation of the abundances in WD J1644-0449, WD J1824+1213, and WD J2317+1830. SDSS J1330+6435 will require stricter abundances to determine its planetesimal's origins, and LHS 2534, as presently modeled, defies all three hypotheses. We find the accretion of an exomoon formed from spalled ring material to be highly unlikely to be the explanation of the lithium excess in any of these cases.

Keywords: Nucleosynthesis, Exoplanets, White dwarf stars, DZ stars, Big Bang nucleosynthesis
Modeling High Mass X-Ray Binaries to Double Neutron Stars through Common Envelope Evolution. We present detailed evolutionary simulations of wide binary systems with high-mass (8–20 M⊙) donor stars and a 1.4 M⊙ neutron star. Mass transfer in such binaries is dynamically unstable, and common envelope (CE) evolution is followed. We use a recently developed prescription to deal with CE evolution and consider various CE ejection efficiencies varying in the range of 0.1–3.0. We focus on the evolutionary consequences of the binaries that survived CE evolution. We demonstrate that it is possible for the binaries to enter a CE decoupling phase (CEDP) when the donor stars are partially stripped, leaving a hydrogen envelope of ≲1.0–4.0 M⊙ after CE evolution. This phase is expected to last ∼104–105 yr, during which mass transfer occurs stably via Roche lobe overflow with super-Eddington rates. Identification of some X-ray binaries in a CEDP is important for the understanding of the physics of CE evolution itself, the origin of ultraluminous X-ray sources, and the recycling process of accreting pulsars. Also, we discuss the formation of double neutron stars and the occurrence of ultrastripped supernovae according to the results from our simulations. On the whole, the properties of post-CE binaries are sensitive to the options of CE ejection efficiencies.

Keywords: Neutron stars, X-ray binary stars, Binary stars, Supernovae, Stellar evolution
Failure of a Solar Filament Eruption Caused by Magnetic Reconnection with Overlying Coronal Loops. The failure of a filament eruption caused by magnetic reconnection between the erupting filament and the overlying magnetic field has been previously proposed in numerical simulations. It is, however, rarely observed. In this study, we report a reconnection between an erupting filament and its overlying coronal loops that results in the failure of the filament eruption. On 2023 September 24, a filament was located in active region 13445. It slowly rose, quickly erupted, rapidly decelerated, then finally stopped, with an untwisting motion. As a failed eruption, the event is associated with an M4.4 flare but no coronal mass ejection. During the eruption, the filament became bright, and the overlying loops appeared first in the high-temperature channels. They have average temperatures of ∼12.8 and ∼9.6 MK, respectively, indicating that both of them were heated. Two sets of new loops, separately connecting the filament endpoints and the overlying loop footpoints, then formed. Subsequently, the heated overlying loops were seen sequentially in the low-temperature channels, showing the cooling process, which is also supported by the light curves. Plasmoids formed and propagated bidirectionally along the filament and the overlying loops, indicating the presence of plasmoid instability. These results suggest that reconnection occurs between the erupting filament and the overlying loops. The erupting filament eventually disappeared, with the appearance of more newly formed loops. We propose that the reconnection between the erupting filament and the overlying loops ruins the filament completely, hence resulting in the failed eruption.

Keywords: Solar active region magnetic fields, Solar flares, Solar magnetic reconnection, Solar extreme ultraviolet emission, Solar ultraviolet emission, Plasma astrophysics, Solar corona, Solar filament eruptions
ATClean: A Novel Method for Detecting Low-luminosity Transients and Application to Pre-explosion Counterparts from SN 2023ixf. In an effort to search for faint sources of emission over arbitrary timescales, we present a novel method for analyzing forced photometry light curves in difference imaging from optical surveys. Our method "ATLAS Clean," or ATClean, utilizes the reported fluxes, uncertainties, and fits to the point-spread function (PSF) from difference images to quantify the statistical significance of individual measurements. We apply this method to control light curves across the image to determine whether any source of flux is present in the data for a range of specific timescales. From ATLAS o-band imaging at the site of the Type II supernova (SN) 2023ixf in M101 from 2015–2023, we show that this method accurately reproduces the 3σ flux limits produced from other, more computationally expensive methods. We derive limits for emission on timescales of 5 days and 80–300 days at the site of SN 2023ixf, which are 19.8 and 21.3 mag, respectively. The latter limits rule out variability for unextinguished red supergiants with initial masses &gt;22 M⊙, comparable to the most luminous predictions for the SN 2023ixf progenitor system. We also compare our limits to short-timescale outbursts, similar to those expected for Type IIn SN progenitor stars or the Type II SN 2020tlf, and rule out outburst ejecta masses of &gt;0.021 M⊙, much lower than the inferred mass of circumstellar matter around SN 2023ixf in the literature. In the future, these methods can be applied to any forced photometry on difference imaging from other surveys, such as Rubin optical imaging.

Keywords: Type II supernovae, Light curves, Circumstellar matter, Core-collapse supernovae
Data-driven Dynamics with Orbital Torus Imaging: A Flexible Model of the Vertical Phase Space of the Galaxy. The vertical kinematics of stars near the Sun can be used to measure the total mass distribution near the Galactic disk and to study out-of-equilibrium dynamics. With contemporary stellar surveys, the tracers of vertical dynamics are so numerous and so well measured that the shapes of underlying orbits are almost directly visible in the data through element abundances or even stellar density. These orbits can be used to infer a mass model for the Milky Way, enabling constraints on the dark matter distribution in the inner galaxy. Here, we present a flexible model for foliating the vertical position─velocity phase space with orbits for use in data-driven studies of dynamics. The vertical acceleration profile in the vicinity of the disk, along with the orbital actions, angles, and frequencies for individual stars, can all be derived from that orbit foliation. We show that this framework—"orbital torus imaging" (OTI)—is rigorously justified in the context of dynamical theory, and does a good job of fitting orbits to simulated stellar abundance data with varying degrees of realism. OTI (1) does not require a global model for the Milky Way mass distribution, and (2) does not require detailed modeling of the selection function of the input survey data. We discuss the approximations and limitations of the OTI framework, which currently trades dynamical interpretability for flexibility in representing the data in some regimes, and which also presently separates the vertical and radial dynamics. We release an open-source tool, torusimaging, to accompany this article.

Keywords: Orbits, Galaxy dynamics, Milky Way dynamics, Dark matter density, Celestial mechanics, Astronomical methods
Imaging and Spectral Fitting of Bright Gamma-Ray Sources with the COSI Balloon Payload. The Compton Spectrometer and Imager balloon payload (COSI-Balloon) is a wide field-of-view Compton gamma-ray telescope that operates in the 0.2–5 MeV bandpass. COSI-Balloon had a successful 46 day flight in 2016 during which the instrument observed the Crab Nebula, Cygnus X-1, and Centaurus A. Using the data collected by the COSI-Balloon instrument during this flight, we present the source flux extraction of signals from the variable balloon background environment and produce images of these background-dominated sources by performing Richardson–Lucy deconvolutions. We also present the spectra measured by the COSI-Balloon instrument, compare and combine them with measurements from other instruments, and fit the data. The Crab Nebula was observed by COSI-Balloon, and we obtain a measured flux in the energy band 325–480 keV of (4.5 ± 1.6) × 103 ph cm‑2 s‑1. The model that best fits the COSI-Balloon data combined with measurements from NuSTAR and Swift-BAT is a broken power law with a measured photon index Γ = 2.20 ± 0.02 above the 43 keV break. Cygnus X-1 was also observed during this flight, and we obtain a measured flux of (1.4 ± 0.2) × 103 ph cm‑2 s‑1 in the same energy band and a best-fit result (including data from NuSTAR, Swift-BAT, and INTEGRAL/IBIS) was a cutoff power law with a high-energy cutoff energy of 138.3 ± 1.0 keV and a photon index of Γ = 1.358 ± 0.002. Finally, we present the measured spectrum of Centaurus A and our best model fit to a power law with a photon index of Γ = 1.73 ± 0.01.

Keywords: Neutron stars, AGN host galaxies, Gamma-ray sources, Gamma-ray detectors, Gamma-ray telescopes, Gamma-ray astronomy, Gamma-rays, Astrophysical black holes
The Red Supergiant Progenitor Luminosity Problem. Analysis of pre-explosion imaging has confirmed red supergiants (RSGs) as the progenitors to Type II-P supernovae (SNe). However, extracting an RSG's luminosity requires assumptions regarding the star's temperature or spectral type and the corresponding bolometric correction, circumstellar extinction, and possible variability. The robustness of these assumptions is difficult to test since we cannot go back in time and obtain additional pre-explosion imaging. Here, we perform a simple test using the RSGs in M31, which have been well observed from optical to mid-IR. We ask the following: By treating each star as if we only had single-band photometry and making assumptions typically used in SN progenitor studies, what bolometric luminosity would we infer for each star? How close is this to the bolometric luminosity for that same star inferred from the full optical-to-IR spectral energy distribution (SED)? We find common assumptions adopted in progenitor studies systematically underestimate the bolometric luminosity by a factor of 2, typically leading to inferred progenitor masses that are systematically too low. Additionally, we find a much larger spread in luminosity derived from single-filter photometry compared to SED-derived luminosities, indicating uncertainties in progenitor luminosities are also underestimated. When these corrections and larger uncertainties are included in the analysis, even the most luminous known RSGs are not ruled out at the 3σ level, indicating there is currently no statistically significant evidence that the most luminous RSGs are missing from the observed sample of II-P progenitors. The proposed correction also alleviates the problem of having progenitors with masses below the expected lower-mass bound for core collapse.

Keywords: Type II supernovae, Massive stars, Core-collapse supernovae
The Prevalence of Star-forming Clumps as a Function of Environmental Overdensity in Local Galaxies. At the peak of cosmic star formation (1 ≲ z ≲ 2), the majority of star-forming galaxies hosted compact, star-forming clumps, which were responsible for a large fraction of cosmic star formation. By comparison, ≲5% of local star-forming galaxies host comparable clumps. In this work, we investigate the link between the environmental conditions surrounding local (z &lt; 0.04) galaxies and the prevalence of clumps in these galaxies. To obtain our clump sample, we use a Faster R-CNN object detection network trained on the catalog of clump labels provided by the Galaxy Zoo: Clump Scout project, then apply this network to detect clumps in approximately 240,000 Sloan Digital Sky Survey galaxies (originally selected for Galaxy Zoo 2). The resulting sample of 41,445 u-band bright clumps in 34,246 galaxies is the largest sample of clumps yet assembled. We then select a volume-limited sample of 9964 galaxies and estimate the density of their local environment using the distance to their projected fifth nearest neighbor. We find a robust correlation between environment and the clumpy fraction (f clumpy) for star-forming galaxies (specific star formation rate, sSFR &gt; 10‑2 Gyr‑1) but find little to no relationship when controlling for galaxies' sSFR or color. Further, f clumpy increases significantly with sSFR in local galaxies, particularly above sSFR &gt; 10‑1 Gyr‑1. We posit that a galaxy's gas fraction primarily controls the formation and lifetime of its clumps, and that environmental interactions play a smaller role.

Keywords: Starburst galaxies, Galaxy formation, Cosmological evolution, Star forming regions, Galaxy structure, Convolutional neural networks, Galaxy evolution, Galaxies
Molecular Distributions and Abundances in the Binary-shaped Outflow of V Hya. Binaries are known to play a key role in the mass loss and dynamical environments of evolved stars. Stellar and substellar companion interactions produce complex wind morphologies including rotating/expanding disks, bipolar outflows, and spiral wind patterns; however, the connection between these many structures and the gas-phase chemistry they harbor is not well constrained. To expand the sample of chemical inventories in interacting systems, we present a detailed spectroscopic case study of the binary C-rich asymptotic giant branch (AGB) star V Hya. Using spatially resolved Atacama Large Millimeter/submillimeter Array observations at Bands 3, 6, and 7, we characterize the rotational emission lines and distributions of molecules in its surrounding disk undergoing dynamical expansion (DUDE). We detect emission from over 15 molecules and isotopologues toward this source, and present resolved maps for the brightest tracers of carbonaceous chemistry (e.g., CCH, C4H, HC5N, HNC, and  ). Employing LTE and non-LTE models of emission from the DUDE, we estimate the abundance distributions for optically thin species, and compare them with prototypical carbon-rich AGB envelopes. We find that the average abundances of detected species are within a factor of ∼5 from sources with similar mass-loss rates; however, the distribution of daughter species in V Hya is much more compact, with carbon chain species (CCH, C4H, and HC3N) appearing with abundances &gt;10−7 even in the innermost sampled regions (200 au) of the disk.

Keywords: Late stellar evolution, Evolved stars, Astrochemistry, Circumstellar matter, Asymptotic giant branch stars
On the Formation of Planets in the Milky Way's Thick Disk. Exoplanet demographic surveys have revealed that close-in (≲1 au) small planets orbiting stars in the Milky Way's thick disk are ∼50% less abundant than those orbiting stars in the Galactic thin disk. One key difference between the two stellar populations is the time at which they emerged: thick-disk stars are the likely product of cosmic noon (redshift z ∼ 2), an era characterized by high star formation rate, massive and dense molecular clouds, and strong supersonic turbulence. Solving for the background radiation field in these early star-forming regions, we demonstrate that protoplanetary disks at cosmic noon experienced radiation fields up to ∼7 orders of magnitude more intense than in solar neighborhood conditions. Coupling the radiation field to a one-dimensional protoplanetary disk evolution model, we find that external UV photoevaporation destroys protoplanetary disks in just ∼0.2–0.5 Myr, limiting the timescale over which planets can assemble. Disk temperatures exceed the sublimation temperatures of common volatile species for ≳Myr timescales, predicting more spatial homogeneity in gas chemical composition. Our calculations imply that the deficit in planet occurrence around thick-disk stars should be even more pronounced for giant planets, particularly those at wide orbital separations, predicting a higher rocky-to-giant planet ratio in the Galactic thick disk versus thin disk.

Keywords: Milky Way Galaxy, Protoplanetary disks, Exoplanets
Extreme Heating of Minor Ions in Imbalanced Solar-wind Turbulence. Minor ions in the solar corona are heated to extreme temperatures, far in excess of those of the electrons and protons that comprise the bulk of the plasma. These highly nonthermal distributions make minor ions sensitive probes of the collisionless processes that heat the corona and power the solar wind. The recent discovery of the "helicity barrier" offers a mechanism in which imbalanced Alfvénic turbulence in low-β plasmas preferentially heats protons over electrons, generating high-frequency, proton-cyclotron-resonant fluctuations. We use the hybrid-kinetic particle-in-cell code Pegasus++ to drive imbalanced Alfvénic turbulence in a 3D low-β plasma with additional passive ion species, He2+ and O5+. A helicity barrier naturally develops, followed by clear phase-space signatures of oblique proton-cyclotron-wave heating and Landau-resonant heating from the imbalanced Alfvénic fluctuations. The former results in characteristically arced ion velocity distribution functions, whose non-bi-Maxwellian features are shown by linear ALPS calculations to be critical to the heating process. Additional features include a steep transition-range electromagnetic spectrum, proton-cyclotron waves propagating in the direction of the imbalance, significantly enhanced proton-to-electron heating ratios, ion temperatures that are considerably more perpendicular with respect to magnetic field, and extreme heating of heavier species in a manner consistent with mass scalings inferred from spacecraft measurements. None of these features are realized in an otherwise equivalent simulation of balanced turbulence. If seen simultaneously in the fast solar wind, these signatures of the helicity barrier would testify to the necessity of incorporating turbulence imbalance in a complete theory for the evolution of the solar wind.

Keywords: Space plasmas, Interplanetary turbulence, Solar coronal heating, Solar wind, Plasma astrophysics
Deep Searches for Radio Pulsations and Bursts from Four Magnetar and a Magnetar-like Pulsar with FAST. We report on radio observations of four magnetars SGR 0501+4516, Swift 1834.9–0846, 1E 1841–045, SGR 1900+14, and a magnetar-like pulsar PSR J1846–0258 with the Five-hundred-meter Aperture Spherical radio Telescope at 1250 MHz. Notably, PSR J1846–0258 was observed 1 month after its 2020 X-ray outburst. The data from these observations were searched for periodic emissions and single pulses. No radio emission was detected for any of our targets. After accounting for the effect of red noise, the nondetections yield stringent upper limits on the radio flux density, with S1250 ≤ 16.9 μJy for the four magnetars and the magnetar-like pulsar, along with constraints on single-pulse flux densities. Our deep radio observations suggest that these magnetars and the magnetar-like pulsar are indeed radio-quiet sources or unfavorably beamed. The resulting flux upper limits, along with previous findings, are discussed, highlighting the significance of further radio observations of radio-quiet magnetars and the high-B magnetar-like pulsar.

Keywords: Magnetars
The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge. We present measurements of the microlensing optical depth and event rate toward the Galactic bulge using the data set from the 2006 to 2014 MOA-II survey, which covers 22 bulge fields spanning ∼42 deg2 between ‑5° &lt; l &lt; 10° and ‑7° &lt; b &lt; ‑1°. In the central region with ∣l∣ &lt; 5°, we estimate an optical depth of   and an event rate of Γ = [16.08 ± 0.28] × 10‑6  using a sample consisting of 3525 microlensing events, with Einstein radius crossing times of tE &lt; 760 days and a source star magnitude of Is &lt; 21.4 mag. We confirm our results are consistent with the latest measurements from the OGLE-IV 8 yr data set. We find our result is inconsistent with a prediction based on Galactic models, especially in the central region with ∣b∣ &lt; 3°. These results can be used to improve the Galactic bulge model, and more central regions can be further elucidated by upcoming microlensing experiments, such as the PRime-focus Infrared Microlensing Experiment and Nancy Grace Roman Space Telescope.

Keywords: Galactic center, Microlensing optical depth, Gravitational microlensing, Microlensing event rate, Milky Way Galaxy