Sazuna/UAT_keywords huggingface dataset:
Search for Extremely Metal-poor Stars with Gemini-N/Graces. I. Chemical-abundance Analysis. We present stellar parameters and abundances of 13 elements for 18 very metal-poor (VMP; [Fe/H] &lt; ─2.0) stars, selected as extremely metal-poor (EMP; [Fe/H] &lt; ─3.0) candidates from the Sloan Digital Sky Survey and Large sky Area Multi-Object Fiber Spectroscopic Telescope survey. High-resolution spectroscopic observations were performed using GEMINI-N/GRACES. We find 10 EMP stars among our candidates, and we newly identify three carbon-enhanced metal-poor stars with [Ba/Fe] &lt; 0. Although chemical abundances of our VMP/EMP stars generally follow the overall trend of other Galactic halo stars, there are a few exceptions. One Na-rich star ([Na/Fe] = +1.14) with low [Mg/Fe] suggests a possible chemical connection with second-generation stars in a globular cluster. The progenitor of an extremely Na-poor star ([Na/Fe] = ─1.02) with high K- and Ni-abundance ratios may have undergone a distinct nucleosynthesis episode, associated with core-collapse supernovae (SNe) having a high explosion energy. We have also found a Mg-rich star ([Mg/Fe] = +0.73) with slightly enhanced Na and extremely low [Ba/Fe], indicating that its origin is not associated with neutron-capture events. On the other hand, the origin of the lowest Mg abundance ([Mg/Fe] = ─0.61) star could be explained by accretion from a dwarf galaxy, or formation in a gas cloud largely polluted by SNe Ia. We have also explored the progenitor masses of our EMP stars by comparing their chemical-abundance patterns with those predicted by Population III SNe models, and find a mass range of 10─26 M ☉, suggesting that such stars were primarily responsible for the chemical enrichment of the early Milky Way.

Keywords: Galaxy chemical evolution, Interstellar abundances, Galaxy stellar content, Chemical abundances, Milky Way Galaxy
HOPS 361-C's Jet Decelerating and Precessing through NGC 2071 IR. We present a two-epoch Hubble Space Telescope study of NGC 2071 IR highlighting HOPS 361-C, a protostar producing an arced 0.2 parsec-scale jet. The proper motions for the brightest knots decrease from 350 to 100 km s-1 with increasing distance from the source. The [Fe II] and Paβ emission line intensity ratio gives a velocity jump through each knot of 40-50 km s-1. A new [O I] 63 μm spectrum, taken with the German REciever for Astronomy at Terahertz frequencies instrument aboard Stratospheric Observatory for Infrared Astronomy, shows a low line-of-sight velocity indicative of high jet inclination. Proper motions and jump velocities then estimate 3D flow speed for knots. Subsequently, we model knot positions and speeds with a precessing jet that decelerates. The measurements are matched with a precession period of 1000-3000 yr and half opening angle of 15°. The [Fe II] 1.26-to-1.64 μm line intensity ratio determines visual extinction to each knot from 5 to 30 mag. Relative to ~14 mag of extinction through the cloud from C18O emission maps, the jet is embedded at a 1/5-4/5 fractional cloud depth. Our model suggests the jet is dissipated over a 0.2 pc arc. This short distance may result from the jet sweeping through a wide angle, allowing the cloud time to fill cavities opened by the jet. Precessing jets contrast with nearly unidirectional protostellar jets that puncture host clouds and can propagate significantly farther.

Keywords: Jets, Herbig-Haro objects, Interstellar dust extinction, Interstellar plasma, Interstellar emissions, Young stellar objects, Dust continuum emission, Proper motions, Nebulae, Protostars, Intercloud medium
Harnessing the Hubble Space Telescope Archives: A Catalog of 21,926 Interacting Galaxies. Mergers play a complex role in galaxy formation and evolution. Continuing to improve our understanding of these systems requires ever larger samples, which can be difficult (even impossible) to select from individual surveys. We use the new platform ESA Datalabs to assemble a catalog of interacting galaxies from the Hubble Space Telescope science archives; this catalog is larger than previously published catalogs by nearly an order of magnitude. In particular, we apply the Zoobot convolutional neural network directly to the entire public archive of HST F814W images and make probabilistic interaction predictions for 126 million sources from the Hubble Source Catalog. We employ a combination of automated visual representation and visual analysis to identify a clean sample of 21,926 interacting galaxy systems, mostly with z &lt; 1. Sixty-five percent of these systems have no previous references in either the NASA Extragalactic Database or Simbad. In the process of removing contamination, we also discover many other objects of interest, such as gravitational lenses, edge-on protoplanetary disks, and "backlit" overlapping galaxies. We briefly investigate the basic properties of this sample, and we make our catalog publicly available for use by the community. In addition to providing a new catalog of scientifically interesting objects imaged by HST, this work also demonstrates the power of the ESA Datalabs tool to facilitate substantial archival analysis without placing a high computational or storage burden on the end user.

Keywords: Computational methods, Interacting galaxies, Catalogs
Self-consistent Spin, Tidal, and Dynamical Equations of Motion in the REBOUNDx Framework. We introduce self-consistent spin, tidal, and dynamical equations of motion into REBOUNDx, a library of additional effects for the popular N-body integrator REBOUND. The equations of motion used are derived from the constant time lag approximation to the equilibrium tide model of tidal friction. These effects will allow the study of a variety of systems of which the full dynamical picture cannot be encapsulated by point particle dynamics. We provide several test cases and benchmark the code's performance against analytic predictions. The open-source code is available in the most recent release of REBOUNDx.

Keywords: Celestial mechanics, Exoplanet tides, N-body simulations
Interpretation of the Observed Neutrino Emission from Three Tidal Disruption Events. Three Tidal Disruption Event candidates (AT2019dsg, AT2019fdr, and AT2019aalc) have been associated with high-energy astrophysical neutrinos in multimessenger follow-ups. In all cases, the neutrino observation occurred ${ \mathcal O }(100)$ days after the maximum of the optical-ultraviolet (OUV) luminosity. We discuss unified fully time-dependent interpretations of the neutrino signals where the neutrino delays are not a statistical effect, but rather the consequence of a physical scale of the post-disruption system. Noting that X-ray flares and infrared (IR) dust echoes have been observed in all cases, we consider three models in which quasi-isotropic neutrino emission is due to the interactions of accelerated protons of moderate, medium, and ultra-high energies with X-rays, OUV, and IR photons, respectively. We find that the neutrino time delays can be well described in the X-ray model assuming magnetic confinement of protons in a calorimetric approach if the unobscured X-ray luminosity is roughly constant over time, and in the IR model, where the delay is directly correlated with the time evolution of the echo luminosity (for which a model is developed here). The OUV model exhibits the highest neutrino production efficiency. In all three models, the highest neutrino fluence is predicted for AT2019aalc, due to its high estimated supermassive black hole mass and low redshift. All models result in diffuse neutrino fluxes that are consistent with observations.

Keywords: Neutrino astronomy, Tidal disruption
Figuring Out Gas &amp; Galaxies in Enzo (FOGGIE). VI. The Circumgalactic Medium of L <SUP>∗</SUP> Galaxies Is Supported in an Emergent, Nonhydrostatic Equilibrium. The circumgalactic medium (CGM) is often assumed to exist in or near hydrostatic equilibrium, with the regulation of accretion and the effects of feedback treated as perturbations to a stable balance between gravity and thermal pressure. We investigate global hydrostatic equilibrium in the CGM using four highly resolved L * galaxies from the Figuring Out Gas &amp; Galaxies in Enzo (FOGGIE) project. The FOGGIE simulations were specifically targeted at fine spatial and mass resolution in the CGM (Δx ≲ 1 kpc h -1 and M ≃ 200M ⊙). We develop a new analysis framework that calculates the forces provided by thermal pressure gradients, turbulent pressure gradients, ram pressure gradients of large-scale radial bulk flows, centrifugal rotation, and gravity acting on the gas in the CGM. Thermal and turbulent pressure gradients vary strongly on scales of ≲5 kpc throughout the CGM. Thermal pressure gradients provide the main supporting force only beyond ~0.25R 200, or ~50 kpc at z = 0. Within ~0.25R 200, turbulent pressure gradients and rotational support provide stronger forces than thermal pressure. More generally, we find that global equilibrium models are neither appropriate nor predictive for the small scales probed by absorption line observations of the CGM. Local conditions generally cannot be derived by assuming a global equilibrium, but an emergent global equilibrium balancing radially inward and outward forces is obtained when averaging over the nonequilibrium local conditions on large scales in space and time. Approximate hydrostatic equilibrium holds only at large distances from galaxies, even when averaging out small-scale variations.

Keywords: Circumgalactic medium
The Rest-frame Submillimeter Spectrum of High-redshift, Dusty, Star-forming Galaxies from the SPT-SZ Survey. We present the average rest-frame spectrum of the final catalog of dusty star-forming galaxies (DSFGs) selected from the South Pole Telescope's SPT-SZ survey and measured with Band 3 of the Atacama Large Millimeter/submillimeter Array. This work builds on the previous average rest-frame spectrum, given in Spilker et al. (2014) for the first 22 sources, and is comprised of a total of 78 sources, normalized by their respective apparent dust masses. The spectrum spans 1.9 &lt; z &lt; 6.9 and covers rest-frame frequencies of 240-800 GHz. Combining this data with low-J CO observations from the Australia Telescope Compact Array, we detect multiple bright line features from 12CO, [C I], and H2O, as well as fainter molecular transitions from 13CO, HCN, HCO+, HNC, CN, H2O+, and CH. We use these detections, along with limits from other molecules, to characterize the typical properties of the interstellar medium (ISM) for these high-redshift DSFGs. We are able to divide the large sample into subsets in order to explore how the average spectrum changes with various galaxy properties, such as effective dust temperature. We find that systems with hotter dust temperatures exhibit differences in the bright 12CO emission lines, and contain either warmer and more excited dense gas tracers or larger dense gas reservoirs. These observations will serve as a reference point to studies of the ISM in distant luminous DSFGs (L IR &gt; 1012 L ☉), and will inform studies of chemical evolution before the peak epoch of star formation at z = 2-3.

Keywords: Cosmology, Strong gravitational lensing, Astrochemistry, Interstellar medium, Ultraluminous infrared galaxies
Investigating the Superorbital Modulations in 4U 1909 + 07, IGR J16418-4532, and IGR J16479-4514 with Swift XRT, BAT, and NuSTAR Observations. A puzzling variety of superorbital modulations has been discovered in several supergiant high mass X-ray binaries (sgHMXBs). To investigate the mechanisms driving these superorbital modulations, we have analyzed long-term Neil Gehrels Swift Observatory (Swift) Burst Alert Telescope (BAT) observations of three sgHMXBs: 4U 1909 + 07, IGR J16418-4532, and IGR J16479-4514, and constructed their dynamic power spectra and superorbital intensity profiles. These Swift BAT observations are complemented by pointed Swift X-ray Telescope (XRT) and Nuclear Spectroscopic Telescope Array (NuSTAR) observations performed near the predicted maximum and minimum phase of a single superorbital cycle for each of these sources. The BAT dynamic power spectra show changes in the strength of the superorbital modulation on timescales of years, with either the peak at the fundamental frequency and/or the second harmonic present at different times for all three sources. The pointed Swift XRT and NuSTAR observations show no significant differences between the pulse profiles and spectral parameters at the superorbital maximum and minimum phase. This is likely due to the fact the superorbital modulation had weakened significantly during the times when the NuSTAR observations were carried out for all three sources. The results from the Swift XRT, BAT, and NuSTAR analysis indicate the possible presence of multiple corotating interaction regions (CIRs) in the stellar winds of the supergiant stars, although a structured stellar wind from the supergiant star due to tidal oscillations cannot be ruled out.

Keywords: Stellar winds, High mass x-ray binary stars, Astronomy data analysis
Measurements of the Crab Pulsar's Giant Radio Pulse Amplitude Power-law Index Using Low-frequency Arecibo and Green Bank Telescope Observations. We report two low-frequency measurements of the power-law index for the amplitudes of giant radio pulses from the Crab pulsar. The two observations were taken with the Arecibo and Green Bank radio telescopes at center frequencies of 327 MHz and 350 MHz, respectively. We find best-fit values for the differential power-law index β (where ${dN}/{dS}\propto {S}^{\beta }$ and S is the pulse amplitude) of -2.63 ± 0.05 and -3.6 ± 0.5 from the Arecibo and Green Bank data sets, respectively. Both values are broadly consistent with other values previously measured for the Crab pulsar at low radio frequencies. These reported values may be useful in future giant pulse studies of the Crab pulsar.

Keywords: Radio transient sources, Pulsars
Exploring the Possible Evolution of the Mass Density Power-law Index of Strong Gravitational Lenses with a Model-independent Method. In this work, we adopt a cosmological model-independent approach for the first time to test the question of whether the mass density power-law index (γ) of strong gravitational lensing systems (SGLSs) evolves with redshift, and the joint light-curve Type Ia supernova (SNe Ia) sample and the quasar sample from Risaliti &amp; Lusso are used to provide the luminosity distances to be calibrated. Our work is based on the flat universe assumption and the cosmic distance duality relation. A reliable data-matching method is used to pair SGLS-SNe and SGLS-quasars. By using the maximum likelihood method to constrain the luminosity distance and γ index, we obtain the likelihood function values for the evolved and nonevolved cases, and then use the Akaike weights and the Bayesian Information Criterion (BIC) selection weights to compare the advantages and disadvantages of these two cases. We find that the γ index is slightly more likely to be a nonevolutionary model for γ = 2 in the case of the currently used samples with low redshift (z  l  &lt; ~ 0.66). With Akaike weights, the relative probabilities are 66.3% versus 33.7% and 69.9% versus 30.1% for the SGLS + SNe Ia sample and SGLS + quasar sample, respectively, and with the BIC selection weights, the relative probabilities are 87.4% versus 12.6% and 52.0% versus 48.0% for the two samples. In the evolving case for the relatively low-redshift lenses (SGLS + SNe Ia), with redshift 0.0625-0.659, $\gamma ={2.058}_{-0.040}^{+0.041}\mbox{--}{0.136}_{-0.165}^{+0.163}z$ . At high redshift (SGLS + quasar), with redshift 0.0625-1.004, $\gamma \,={2.051}_{-0.077}^{+0.076}\mbox{--}{0.171}_{-0.196}^{+0.214}z$ . Although not the more likely model, this evolved γ case also fits the data well, with a negative and mild evolution for both low- and high-redshift samples.

Keywords: Strong gravitational lensing, Supernovae, Quasars
Inflation from Multiple Pseudo-scalar Fields: Primordial Black Hole Dark Matter and Gravitational Waves. We study a model of inflation with multiple pseudo-scalar fields coupled to a U(1) gauge field through Chern-Simons interactions. Because of parity-violating interactions, one polarization of the gauge field is amplified, yielding to an enhanced curvature perturbation power spectrum. Inflation proceeds in multiple stages, as each pseudo-scalar field rolls toward its minimum, yielding to distinct multiple peaks in the curvature perturbation power spectra at various scales during inflation. The localized peaks in the power spectra generate primordial black holes that can furnish a large fraction of dark matter abundance. In addition, gravitational waves with nontrivial spectra are generated that are in the sensitivity ranges of various forthcoming GW observatories.

Keywords: Cosmic inflation, Gravitational waves, Primordial black holes, Cosmological perturbation theory
Redshift Evolution of the Feedback-Cooling Equilibrium in the Core of 48 SPT Galaxy Clusters: A Joint Chandra-SPT-ATCA Analysis. We analyze the cooling and feedback properties of 48 galaxy clusters at redshifts 0.4 &lt; z &lt; 1.3 selected from the South Pole Telescope (SPT) catalogs to evolve like the progenitors of massive and well-studied systems at z ~ 0. We estimate the radio power at the brightest cluster galaxy (BCG) location of each cluster from an analysis of Australia Telescope Compact Array data. Assuming that the scaling relation between the radio power and active galactic nucleus (AGN) cavity power P cav observed at low redshift does not evolve with redshift, we use these measurements in order to estimate the expected AGN cavity power in the core of each system. We estimate the X-ray luminosity within the cooling radius L cool of each cluster from a joint analysis of the available Chandra X-ray and SPT Sunyaev-Zel'dovich (SZ) data. This allows us to characterize the redshift evolution of the P cav/L cool ratio. When combined with low-redshift results, these constraints enable investigations of the properties of the feedback-cooling cycle across 9 Gyr of cluster growth. We model the redshift evolution of this ratio measured for cool-core clusters by a log-normal distribution $\mathrm{Log}$ - ${ \mathcal N }(\alpha +\beta z,{\sigma }^{2})$ and constrain the slope of the mean evolution to β = -0.05 ± 0.47. This analysis improves the constraints on the slope of this relation by a factor of two. We find no evidence of redshift evolution of the feedback-cooling equilibrium in these clusters, which suggests that the onset of radio-mode feedback took place at an early stage of cluster formation. High values of P cav/L cool are found at the BCG location of noncool-core clusters, which might suggest that the timescales of the AGN feedback cycle and the cool core-noncool core transition are different. This work demonstrates that the joint analysis of radio, SZ, and X-ray data solidifies the investigation of AGN feedback at high redshifts.

Keywords: Galaxy clusters, X-ray astronomy, Sunyaev-Zeldovich effect, Active galactic nuclei, Radio active galactic nuclei
On the Reionization-era Globular Cluster in the Low-mass Galaxy Eridanus II. Using color-magnitude diagrams from deep archival Hubble Space Telescope imaging, we self-consistently measure the star formation history of Eridanus II (Eri II), the lowest-mass galaxy (M ⋆(z = 0) ~ 105 M ⊙) known to host a globular cluster (GC), and the age, mass, and metallicity of its GC. The GC (~13.2 ± 0.4 Gyr, &lt;[Fe/H]&gt; = -2.75 ± 0.2 dex) and field (mean age ~13.5 ± 0.3 Gyr, &lt;[Fe/H]&gt; = -2.6 ± 0.15 dex) have similar ages and metallicities. Both are reionization-era relics that formed before the peak of cosmic star and GC formation (z ~ 2-4). The ancient star formation properties of Eri II are not extreme and appear similar to z = 0 dwarf galaxies. We find that the GC was ≲4 times more massive at birth than today and was ~10% of the galaxy's stellar mass at birth. At formation, we estimate that the progenitor of Eri II and its GC had M UV ~ -7 to -12, making it one of the most common type of galaxy in the early universe, though it is fainter than direct detection limits, absent gravitational lensing. Archaeological studies of GCs in nearby low-mass galaxies may be the only way to constrain GC formation in such low-mass systems. We discuss the strengths and limitations in comparing archaeological and high-redshift studies of cluster formation, including challenges stemming from the Hubble Tension, which introduces uncertainties into the mapping between age and redshift.

Keywords: Globular star clusters, Dwarf galaxies, Local Group
Energy Spectrum of Solar Energetic Electron Events over 25 Years. We investigate the peak flux energy spectrum of 458 solar energetic electron (SEE) events with a clear velocity dispersion detected at energies from ≤4.2 to ≥108 keV by Wind/3DP from 1994 December through 2019 December, utilizing a pan-spectrum fitting method. According to the fitted spectral parameters, these 458 events are self-consistently classified into five spectral types: 304 downward double-power-law (DDPL) events, 32 upward double-power-law (UDPL) events, 23 single-power-law (SPL) events, 44 Ellison-Ramaty (ER) events, and 55 logarithmic-parabola (LP) events. The DDPL events can be further divided into two types: 231 ${\mathrm{DDPL}}_{{E}_{B}\geqslant 20\mathrm{keV}}$ events and 73 ${\mathrm{DDPL}}_{{E}_{B}\lt 20\mathrm{keV}}$ events, since their break energy E  B  exhibits a double-peak distribution separated by a dip at ~20 keV. The ${\mathrm{DDPL}}_{{E}_{B}\lt 20\mathrm{keV}}$ ( ${\mathrm{DDPL}}_{{E}_{B}\geqslant 20\mathrm{keV}}$ ) events show a power-law spectral index of ${2.0}_{-0.2}^{+0.2}$ ( ${2.1}_{-0.3}^{+0.3}$ ) at energies below ${E}_{B}={5.6}_{-2.4}^{+2.3}$ ( ${61}_{-12}^{+23}$ ) keV and an index of ${3.3}_{-0.3}^{+0.5}$ ( ${3.9}_{-0.7}^{+0.6}$ ) at energies above. The UDPL events have a spectral index of ${3.0}_{-0.3}^{+0.3}$ at energies below ${E}_{B}={5.1}_{-1.8}^{+4.2}$ keV and an index of ${2.2}_{-0.3}^{+0.2}$ at energies above. The SPL events exhibit a spectral index of ${2.8}_{-0.2}^{+0.5}$ . The ER events show a spectral index of ${1.9}_{-0.3}^{+0.3}$ at energies below ${E}_{c}={31}_{-11}^{+19}$ keV. The LP events are characterized by a spectral slope of ${1.8}_{-0.3}^{+0.4}$ ( ${3.6}_{-0.5}^{+0.7}$ ) at 2.8 keV (108 keV). The six spectral types also behave differently in the relationship between spectral parameters and in solar cycle variations. The spectral shape of most SEE events appears to be unrelated to the estimated electron path lengths. These results suggest that the formation of SEE events can involve complex processes/sources.

Keywords: Solar energetic particles, Solar particle emission