Sazuna/UAT_keywords huggingface dataset:
A Systematic Study of Ia-CSM Supernovae from the ZTF Bright Transient Survey. Among the supernovae (SNe) that show strong interaction with a circumstellar medium (CSM), there is a rare subclass of Type Ia supernovae, SNe Ia-CSM, which show strong narrow hydrogen emission lines much like SNe IIn but on top of a diluted Type Ia spectrum. The only previous systematic study of this class identified 16 SNe Ia-CSM, eight historic and eight from the Palomar Transient Factory (PTF). Now using the successor survey to PTF, the Zwicky Transient Facility (ZTF), we have classified 12 additional SNe Ia-CSM through the systematic Bright Transient Survey (BTS). Consistent with previous studies, we find these SNe to have slowly evolving optical light curves with peak absolute magnitudes between -19.1 and -21, spectra having weak Hβ and large Balmer decrements of ~7. Out of the 10 SNe from our sample observed by NEOWISE, nine have 3σ detections, with some SNe showing a reduction in the red wing of Hα, indicative of newly formed dust. We do not find our SN Ia-CSM sample to have a significantly different distribution of equivalent widths of He I λ5876 than SNe IIn as observed in Silverman et al. The hosts tend to be late-type galaxies with recent star formation. We derive a rate estimate of ${29}_{-21}^{+27}$ Gpc-3 yr-1 for SNe Ia-CSM, which is ~0.02%-0.2% of the SN Ia rate. We also identify six ambiguous SNe IIn/Ia-CSM in the BTS sample and including them gives an upper limit rate of 0.07%-0.8%. This work nearly doubles the sample of well-studied Ia-CSM objects in Silverman et al., increasing the total number to 28.

Keywords: Type Ia supernovae, Supernovae
Plausible Constraints on the Range of Bulk Terrestrial Exoplanet Compositions in the Solar Neighborhood. Rocky planet compositions regulate planetary evolution by affecting core sizes, mantle properties, and melting behaviors. Yet, quantitative treatments of this aspect of exoplanet studies remain generally underexplored. We attempt to constrain the range of potential bulk terrestrial exoplanet compositions in the solar neighborhood (&lt;200 pc). We circumscribe probable rocky exoplanet compositions based on a population analysis of stellar chemical abundances from the Hypatia and GALAH catalogs. We apply a devolatilization model to simulate compositions of hypothetical, terrestrial-type exoplanets in the habitable zones around Sun-like stars, considering elements O, S, Na, Si, Mg, Fe, Ni, Ca, and Al. We further apply core-mantle differentiation by assuming constant oxygen fugacity, and model the consequent mantle mineralogy with a Gibbs energy minimization algorithm. We report statistics on several compositional parameters and propose a reference set of (21) representative planet compositions for use as end-member compositions in imminent modeling and experimental studies. We find a strong correlation between stellar Fe/Mg and metallic-core sizes, which can vary from 18 to 35 wt%. Furthermore, stellar Mg/Si gives a first-order indication of mantle mineralogy, with high-Mg/Si stars leading to weaker, ferropericlase-rich mantles, and low-Mg/Si stars leading to mechanically stronger mantles. The element Na, which modulates crustal buoyancy and mantle clinopyroxene fraction, is affected by devolatilization the most. While we find that planetary mantles mostly consist of Fe/Mg silicates, the core sizes and relative abundances of common minerals can nevertheless vary significantly among exoplanets. These differences likely lead to different evolutionary pathways among rocky exoplanets in the solar neighborhood.

Keywords: Planetary mineralogy, Chemical abundances, Galaxy chemical evolution, Planetary geology
Nature and Nurture? Comparing Lyα Detections in UV-bright and Fainter [O III]+Hβ Emitters at z   8 with Keck/MOSFIRE. The 100% detection rate of Lyα emission in a sample of four luminous z ~ 8 galaxies with red Spitzer/IRAC colors suggests objects with unusual ionizing capabilities that created early ionized bubbles in a neutral era. Whether such bubbles reflect enhanced ionizing properties (nature) or an overdense environment (nurture), however, remains unclear. Here we aim to distinguish between these hypotheses via a search for Lyα emission in five fainter galaxies drawn from the CANDELS-GOODS fields using a similar IRAC excess and UV magnitudes that should reflect reduced clustering effects. Using Keck/MOSFIRE we tentatively detect &gt;4σ line emission in only two targets at redshifts z Lyα  = 7.1081 and 7.9622 with rest-frame EWs of 16-17 Å, ~1.5× weaker compared to their brighter counterparts. Thus, we find a reduced rate for Lyα emission of ${0.40}_{-0.25}^{+0.30}$ compared to ${1.00}_{-0.44}^{+0.00}$ for more luminous examples. The lower rate agrees with predictions from simulations of a mostly neutral intergalactic medium and an intrinsic EW0,Lyα  distribution for z ~ 6 galaxies. However, even with an extreme EW0,Lyα  model, it is challenging to match the detection rate for the luminous objects. Spectral energy distribution fitting of our fainter sample indicates young and star-forming systems, albeit with less extreme star formation rates and ionization parameters compared to their luminous counterparts. The enhanced Lyα rate in luminous galaxies is thus likely a byproduct of both extreme ionizing properties as well as environmental effects. Further studies with JWST may be required to resolve the physical nature of this puzzling population.

Keywords: Lyman-alpha galaxies, Reionization, Star formation, Galaxies
The Astrodust+PAH Model: A Unified Description of the Extinction, Emission, and Polarization from Dust in the Diffuse Interstellar Medium. We present a new model of interstellar dust in which large grains are a single composite material, "astrodust," and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a single-composition model for grains larger than ~0.02 μm most naturally explains the lack of frequency dependence in the far-infrared (FIR) polarization fraction and the characteristic ratio of optical to FIR polarization. We derive a size distribution and alignment function for 1.4:1 oblate astrodust grains that, with PAHs, reproduce the mean wavelength dependence and polarization of Galactic extinction and emission from the diffuse interstellar medium while respecting constraints on solid-phase abundances. All model data and Python-based interfaces are made publicly available.

Keywords: Dust physics, Dust composition, Interstellar dust extinction, Dust formation, Astrophysical dust processes, Starlight polarization, Dust continuum emission, Interstellar dust processes, Optical constants (Dust)
The Spherical Fast Multipole Method (sFMM) for Gravitational Lensing Simulation. In this paper, we present a spherical Fast Multipole Method (sFMM) for ray-tracing simulation of gravitational lensing on a curved sky. The sFMM is a nontrivial extension of the Fast Multiple Method to sphere ${{\mathbb{S}}}^{2}$ , and it can accurately solve the Poisson equation with time complexity of $O(N)\mathrm{log}(N)$ , where N is the number of particles. It is found that the time complexity of the sFMM is near O(N) and the computational accuracy can reach 10-10 in our test. In addition, compared with the Fast Spherical Harmonic Transform, the sFMM is not only faster but also more accurate, as it has the ability to reserve high-frequency components of the density field. These merits make the sFMM an optimum method to simulate the gravitational lensing on a curved sky, which is the case for upcoming large-area sky surveys, such as the Vera Rubin Observatory and the China Space Station Telescope.

Keywords: Gravitational lensing, Algorithms, N-body simulations
An SMA Survey of Chemistry in Disks Around Herbig AeBe Stars. Protoplanetary disks around Herbig AeBe stars are exciting targets for studying the chemical environments where giant planets form. Save for a few disks, however, much of Herbig AeBe disk chemistry is an open frontier. We present a Submillimeter Array ~213-268 GHz pilot survey of millimeter continuum CO isotopologs and other small molecules in disks around five Herbig AeBe stars (HD 34282, HD 36112, HD 38120, HD 142666, and HD 144432). We detect or tentatively detect 12CO 2-1 and 13CO 2-1 from four disks, C18O 2-1 and HCO+ 3-2 from three disks, HCN 3-2, CS 5-4, and DCO+ 3-2 from two disks, and C2H 3-2 and DCN 3-2 from one disk each. H2CO 3-2 is undetected at the sensitivity of our observations. The millimeter continuum images of HD 34282 suggest a faint, unresolved source ~5.″0 away, which could arise from a distant orbital companion or an extended spiral arm. We fold our sample into a compilation of T Tauri and Herbig AeBe/F disks from the literature. Altogether, most line fluxes generally increase with millimeter continuum flux. Line flux ratios between CO 2-1 isotopologs are nearest to unity for the Herbig AeBe/F disks. This may indicate emitting layers with relatively similar, warmer temperatures and more abundant CO relative to the disk dust mass. Lower HCO+ 3-2 flux ratios may reflect lower ionization in Herbig AeBe/F disks. Lower detection rates and flux ratios for DCO+ 3-2, DCN 3-2, and H2CO 3-2 suggest smaller regimes of cold chemistry around the luminous Herbig AeBe/F stars.

Keywords: Interferometry, Protoplanetary disks, Interstellar medium, Astrochemistry
On the Energy-specific Photodissociation Pathways of <SUP>14</SUP>N<SUB>2</SUB> and <SUP>14</SUP>N<SUP>15</SUP>N Isotopomers to N Atoms of Different Reactivity: A Quantum Dynamical Perspective. Photodissociation of the nitrogen molecule in the vacuum ultraviolet (VUV) is a major source of reactive nitrogen atoms in the upper atmosphere of Earth and throughout the solar system. Recent experimental studies have revealed strong energy dependence of the VUV photodissociation branching ratios to the N(4S3/2)+N(2D J ) and N(4S3/2)+N(2P J ) product channels, the primary dissociation pathways in the 108,000-116,000 cm-1 energy region. This produces N(2D J ) and N(2P J ) excited atoms that differ significantly in their chemical reactivity. The branching ratios oscillate with increase in the VUV excitation energy. We use high-level ab initio quantum chemistry to compute the potential curves of 17 electronic excited states and their nonadiabatic and spin-orbit couplings. The dynamics follow the sequential evolution from the optically excited but bound ${}^{1}{{\rm{\Sigma }}}_{u}^{+}$ singlets. Spin-orbit coupling enables transfer to the dissociative triplet and quintet states. We compute the photodissociation yields through the dense manifold of electronic states leading to both exit channels. The dynamical simulations accurately capture the branching oscillations and enable a detailed look into the photodissociation mechanism. The major contribution to the dissociation is through the two lowest 3Π u  states. However, for both isotopomers, at about 110,000 cm-1 there is an abnormally low dissociation rate into the N(4S3/2)+N(2P J ) channel that enables comparable participation of triplet ${}^{3}{{\rm{\Sigma }}}_{u}^{-}$ and quintet 5Π u  electronic states. This leads to the first peak in the branching ratio. At higher energies, trapping of the population in the 33Π u  bound triplet state occurs. This favors dissociation to the lower-energy N(4S3/2)+N(2D J ) channel and results in the observed second switch in branching ratios.

Keywords: Isotopic abundances, Cosmochemistry, Theoretical models, Photodissociation reactions, Reaction rates, Ultraviolet spectroscopy, Small molecules
Population of X-Ray Sources in the Intermediate-age Cluster NGC 3532: a Test Bed for Machine-learning Classification. Open clusters are thought to be the birthplace of most stars in the galaxy. Thus, they are excellent laboratories for investigating stellar evolution, and X-ray properties of various types of stars (including binary stars, evolved stars, and compact objects). In this work, we investigate the population of X-ray sources in the nearby 300 Myr old open cluster NGC 3532 using Chandra X-ray Observatory and multiwavelength data from several surveys. We apply a random-forest machine-learning pipeline (MUWCLASS) to classify all confidently detected X-ray sources (signal-to-noise ratio, hereafter S/N, &gt; 5) in the field of NGC 3532. We also perform a more detailed investigation of brighter sources, including their X-ray spectra and lightcurves. Most X-ray sources are confirmed as coronally active low-mass stars, many of which are confidently identified by MUWCLASS. Several late B- or early A-type stars are relatively bright in X-rays, most of which are likely binaries. We do not find any compact objects among X-ray sources reliably associated with NGC 3532, down to the limiting X-ray flux of ~2 × 10-15 erg s-1cm-2, corresponding to L X ~ 6 × 1028 erg s-1 at the cluster's distance. We also identify several Galactic sources beyond NGC 3532 that differ from typical coronally active stars, and were classified by MUWCLASS as potential compact objects. Detailed investigation reveals that these sources may indeed belong to rarer classes, and deserve follow-up observations.

Keywords: Astrostatistics tools, Classification, Catalogs, X-ray surveys, X-ray sources, Compact objects, Low mass stars, Open star clusters, Random Forests, Astronomy data visualization, X-ray stars
Mapping Protoplanetary Disk Vertical Structure with CO Isotopologue Line Emission. High-spatial-resolution observations of CO isotopologue line emission in protoplanetary disks at mid-inclinations (≍30°─75°) allow us to characterize the gas structure in detail, including radial and vertical substructures, emission surface heights and their dependencies on source characteristics, and disk temperature profiles. By combining observations of a suite of CO isotopologues, we can map the two-dimensional (r, z) disk structure from the disk upper atmosphere, as traced by CO, to near the midplane, as probed by less abundant isotopologues. Here, we present high-angular-resolution (≲0.″1 to ≍0.″2; ≍15─30 au) observations of CO, 13CO, and C18O in either or both J = 2─1 and J = 3─2 lines in the transition disks around DM Tau, Sz 91, LkCa 15, and HD 34282. We derived line emission surfaces in CO for all disks and in 13CO for the DM Tau and LkCa 15 disks. With these observations, we do not resolve the vertical structure of C18O in any disk, which is instead consistent with C18O emission originating from the midplane. Both the J = 2─1 and J = 3─2 lines show similar heights. Using the derived emission surfaces, we computed radial and vertical gas temperature distributions for each disk, including empirical temperature models for the DM Tau and LkCa 15 disks. After combining our sample with literature sources, we find that 13CO line emitting heights are also tentatively linked with source characteristics, e.g., stellar host mass, gas temperature, disk size, and show steeper trends than seen in CO emission surfaces.

Keywords: High angular resolution, Protoplanetary disks, Planet formation, CO line emission
Extended Hard X-Ray Emission in Highly Obscured AGNs. Kiloparsec-scale hard (&gt;3 keV) X-ray continuum and fluorescent Fe Kα line emission has been recently discovered in nearby Compton-thick (CT) active galactic nuclei (AGNs), which opens new opportunities to improve AGN torus modeling and investigate how the central supermassive black hole interacts with and impacts the host galaxy. Following a pilot Chandra survey of nearby CT AGNs, we present in this paper the results of Chandra spatial analysis of five uniformly selected non-CT but still heavily obscured AGNs to investigate the extended hard X-ray emission by measuring the excess emission counts, excess fractions, and physical scales. Three of these AGNs show extended emission in the 3.0-7.0 keV band detected at &gt;3σ above the Chandra point-spread function with total excess fractions ranging from ~8% to 20%. The extent of the hard emission ranges from at least ~250 pc to 1.1 kpc in radius. We compare these new sources with CT AGNs and find that CT AGNs appear to be more extended in the hard band than the non-CT AGNs. Similar to CT AGNs, the amounts of extended hard X-ray emission relative to the total emission of these obscured AGNs are not negligible. Together with other AGNs detected with extended hard X-ray emission in the literature, we further explore potential correlations between the extended hard X-ray component and AGN parameters. We also discuss the implications for torus modeling and AGN feedback. Considering potential contributions from X-ray binaries (XRBs) to the extended emission, we do not see strong XRB contamination in the overall sample.

Keywords: AGN host galaxies, Active galaxies, X-ray active galactic nuclei
Synchrotron Cutoff in Ultraluminous X-Ray Sources. The origin of spectral curvature at energies E ≃ 10 keV in ultraluminous X-ray sources (ULXs) is not well understood. In this paper, we propose a novel mechanism based on synchrotron radiation to explain this cutoff. We show that relativistic plasma can give rise to the observed spectral curvature for neutron star magnetic fields due to the variation in the latitude of synchrotron radiation. We analyze the NuSTAR data of two bright pulsar ULXs, NGC 5907 ULX1 and NGC 7793 P13, and provide estimates of the physical parameters of these sources. We fit the data for synchrotron emission at various latitudes and show that the spectral cutoff in these cases can be explained for a large range of acceptable physical parameters, e.g., a semirelativistic plasma with γ ≃ 20 for high latitudes or a highly relativistic plasma (γ ≃ 105) for emission close to the electron's orbital plane in a typical magnetic field of B ≃ 1012 G. We also discuss how such an emission mechanism can be distinguished from other proposed models. A corollary to our study is that most ULXs might be neutron stars as they display such a spectral cutoff.

Keywords: Neutron stars, Ultraluminous x-ray sources, High energy astrophysics, Radiative processes
The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. VI. The Star Formation History and Dust Production in Andromeda IX. We present a photometric study of the resolved stellar populations in Andromeda IX (And IX), the closest satellite to M31, a metal-poor and low-mass dwarf spheroidal galaxy. We estimate a distance modulus of ${24.56}_{-0.15}^{+0.05}$ mag based on the tip of the red giant branch. By probing the variability of asymptotic giant branch stars, we study the star formation history of And IX. We identified 50 long-period variables (LPVs) in And IX using the Isaac Newton Telescope in two filters, the Sloan $i^{\prime} $ and Harris V. In this study, we selected LPVs within two half-light radii with amplitudes in the range of 0.2-2.20 mag. It is found that the peak of star formation reaches ~8.2 ± 3.1 × 10-4 M ☉ yr-1 at ≈6 Gyr ago. Our findings suggest an outside-in galaxy formation scenario for And IX with a quenching occurring ${3.65}_{-0.13}^{+1.52}$ Gyr ago with a star formation rate (SFR) in the order of 2.0 × 10-4 M ☉ yr-1 at redshift &lt;0.5. We calculate the total stellar mass by integrating the SFR within two half-light radii ~3.0 × 105 M ☉. By employing spectral energy distribution fitting for the observed LPVs in And IX, we evaluate a mass-loss rate in the range of 10-7 ≤ $\dot{M}$ ≤ 10-5 M ☉ yr-1. Finally, we show that the total mass deposition to the interstellar medium (ISM) is ~2.4 × 10-4 M ☉ yr-1 from the C- and O-rich types of dust-enshrouded LPVs. The ratio of the total mass returned to the ISM by LPVs to the total stellar mass is ~8.0 × 10-10 yr-1, and so at this rate it would take ~1 Gyr to reproduce this galaxy.

Keywords: Local Group, Evolved stars, Dwarf galaxies, Stellar mass loss, Asymptotic giant branch stars, Star formation, Dwarf spheroidal galaxies
Starspot Mapping with Adaptive Parallel Tempering. II. Application to TESS Data for M-dwarf Flare Stars AU Microscopii, YZ Canis Minoris, and EV Lacertae. Starspots and stellar flares are indicators of stellar magnetic activity. The magnetic energy stored around spots is thought to be the origin of flares, but the connection is not completely understood. To investigate the relation between spot locations deduced from light curves and the occurrence of flares therein, we perform starspot modeling for the TESS light curves of three M-dwarf flare stars, AU Mic, YZ CMi, and EV Lac, using the code implemented in Paper I. The code enables us to deduce multiple stellar/spot parameters by the adaptive parallel tempering algorithm efficiently. We find that flare occurrence frequency is not necessarily correlated with the rotation phases of the light curve for each star. The result of starspot modeling shows that any spot is always visible to the line of sight in all phases, and we suggest that this can be one of the reasons why there is no or low correlation between rotation phases and flare frequency. In addition, the amplitude and shape of the light curve for AU Mic and YZ CMi have varied in two years between different TESS cycles. The result of starspot modeling suggests that this can be explained by the variations of spot size and latitude.

Keywords: M dwarf stars, Starspots, Model selection, Importance sampling, Astrostatistics, Stellar flares, Markov chain Monte Carlo
The Initial Mass Function and Other Stellar Properties Across the Core of the Hydra I Cluster. The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in the core of its two brightest galaxies. In addition, the differing kinematics of the two galaxies allows a test of the local validity of general scaling relations. In this work, we present a direct comparison employing full spectral fitting of new high-quality long-slit optical and near-infrared spectroscopic data. We retrieve age, metallicity, and 19 elemental abundances out to ~12 kpc within each galaxy, as well as the Initial Mass Function (IMF) in their central regions. Our results suggest that the inner ~5 kpc regions of both galaxies, despite their different masses, formed at the same time and evolved with a similar star formation timescale and chemical enrichment, confirming their early formation in the cluster buildup. Only the overall metallicity and IMF radial profiles show differences connected with their different velocity dispersion profiles. The radial trends of the IMF positively correlate with both [Z/H] and σ. While the trends of the IMF slope values with metallicity agree with a global trend for both galaxies, the trends with the velocity dispersion exhibit differences. The outer regions show signs of mixed stellar populations with large differences in chemical content compared to the centers, but with similarly old ages. * This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Initial mass function, Early-type galaxies