Sazuna/UAT_keywords huggingface dataset:
The Recurrent Nova IM Normae: A UV Spectroscopic Twin of T Pyxidis. We present an HST COS spectrum of the short orbital period recurrent nova IM Normae. We compare its far-ultraviolet spectrum with the HST COS spectrum of the recurrent nova T Pyxidis, both spectra obtained in deep quiescence. Despite the poor signal-to-noise ratio of the IM Nor spectrum, it seems clear that the two recurrent novae are quite similar to each other. This conclusion is consistent with optical similarities in their light curves. In terms of distinctions, the presence of higher excitation features such as O V (1371) and N V (1240) in IM Nor may suggest that the accretion disk is hotter and the accretion rate is higher than those of T Pyx.

Keywords: White dwarf stars, Type Ia supernovae, Recurrent novae, Stellar accretion, Cataclysmic variable stars
Modeling Star Formation Histories of Post Starburst Galaxies with BAGPIPES. Post-starburst galaxies provide insights into quenching mechanisms. While these galaxies show signs of quiescence, obtaining accurate star formation rates (SFRs) is difficult. This research uses BAGPIPES, a Bayesian spectrum-fitting code, to obtain model spectra of 13 galaxies. From these models, we calculate SFRs over 10 and 100 Myr durations. We compare these SFRs to published Hα and total infrared (TIR) SFRs to examine biases in these measurements. We find that the BAGPIPES-inferred 10, 100 Myr SFRs are comparable with Hα and TIR traced SFRs, respectively, with longer-duration tracers showing systematically higher SFRs.

Keywords: Galaxy quenching, Galaxies, Galaxy evolution, Post-starburst galaxies
Spectroscopic Confirmation of the Nearby, Wide-separation L Dwarf Pair CWISE J061741.79+194512.8AB. We present spectroscopic confirmation of a nearby L dwarf pair, CWISE J061741.79+194512.8AB. Keck/NIRES near-infrared spectroscopy shows that the pair is composed of an L2 dwarf primary and an L4 dwarf secondary. High resolution spectroscopy of the combined light system with Keck/NIRSPEC yields a radial velocity of 29.2 ± 0.3 km s-1 and a projected rotational velocity $v\sin i\,$ = $\,{41.6}_{-2.6}^{+2.7}$ km s-1. Our spectrophotometric distance estimate places the system at 28.2 ± 5.7 pc, significantly more distant than originally estimated in Kirkpatrick et al. The angular separation of the components is 1.″31 ± 0.″14, corresponding to a projected physical separation of 37 ± 8 au.

Keywords: Brown dwarfs, Binary stars, Low mass stars
CO Fundamental and First Overtone Emission in the Nova V496 Scuti. Simultaneous spectroscopic observations of the carbon monoxide (CO) fundamental and first overtone emission are presented for the nova V496 Scuti. Total emission is comparable in the two features, indicating that optically thick conditions (optical depth τ ≈ 100) exist in the fundamental. Analysis of the first overtone suggests a temperature for the CO emitting region of ≥4000 K and a 13C to 12C ratio of 0.7 ± 0.1. Concurrent observations by Raj et al., found emission lines of C I and O I present at this time, indicating that carbon monoxide formation did not fully incorporate either of these two elements.

Keywords: Novae
ALMA Band-7 Flux Density Prediction of the Haumea Ring System for Ongoing Observations. In 2017, multi-chord occultation observations found a ring around the dwarf planet (136108) Haumea, and provided direct measurements of the size and an estimate of the apparent opacity of the ring system. Based on these properties, Müller et al. estimated the thermal contribution of Haumea's ring at 20-500 μm. Here, we predict the flux densities of the ring of Haumea at ~870 μm for ongoing measurements with ALMA.

Keywords: Small Solar System bodies
Does Intelligence Matter? An Interdisciplinary Guidance Statement on the Search for Extraterrestrial Intersections. Attendees at the 2023 Penn State SETI Symposium participated in a workshop series entitled "The Moral Relevance of Intelligence in the Search for Extraterrestrial Life." This breakout series focused interdisciplinary dialogs on the role intelligence plays in the search for extraterrestrials. A moderated inquiry took place over the course of two days, resulting in a Guiding Statement on Extraterrestrial Intersections in support of interdisciplinary, ethics-informed engagement and research related to the search for extraterrestrials.

Keywords: Biosignatures, Search for extraterrestrial intelligence, Technosignatures
Bright Beacons? ALMA Non-detection of a Supposedly Bright [O I] 63 μm Line in a Redshift-6 Dusty Galaxy. We report a non-detection of the [O I] 63 μm emission line from the z = 6.03 galaxy G09.83808 using ALMA Band 9 observations, refuting the previously claimed detection with APEX by Rybak et al.; the new upper limit on the [O I] 63 μm flux is almost 20-times lower. [O I] 63 μm line could be a powerful tracer of neutral gas in the Epoch of Reionization: yet our null result shows that detecting [O I] 63 μm from z ≥ 6 galaxies is more challenging than previously hypothesized.

Keywords: Submillimeter astronomy, High-redshift galaxies, Interstellar medium
Can LISA Resolve Black Hole Binaries in the M87 Globular Clusters?. As stellar black holes (BHs) interact with one another in globular clusters, BH binaries form, inspiral, and merge via gravitational wave emission. These dynamically formed BH binaries may account for a fraction of the sources observed by LIGO/Virgo and, earlier in their inspirals, may be detected at millihertz frequencies by LISA in nearby galaxies. M87, known to contain over 104 globular clusters, is a promising candidate for such millihertz sources. Utilizing N-body cluster simulations, we investigate the binary BH population in M87 clusters. Although thousands of sources in LISA's frequency range (10-5-1 Hz) are expected in M87's clusters, we predict none are resolvable with sufficiently high signal-to-noise ratios. We predict the nearest globular clusters in the Milky Way and clusters found in distant galaxies (d ≳ 100 Mpc) near LISA's detection horizon for stellar BH binaries are more promising hosts of resolvable LISA sources.

Keywords: Globular star clusters, N-body simulations, Stellar mass black holes, Gravitational wave sources
Improved Redshifts for DESI EDR Quasars. The Dark Energy Spectroscopic Instrument (DESI) survey will provide optical spectra for ~3 million quasars. Accurate redshifts for these quasars will facilitate a broad range of science applications. Here we provide improved systemic redshift estimates for the ~95k quasars included in the DESI Early Data Release (EDR), based on emission-line fits to the quasar spectra. The majority of the DESI pipeline redshifts are reliable. However, ~19% of the EDR quasars have pipeline redshifts that deviate from our new redshifts by &gt;500 km s-1. We use composite quasar spectra to demonstrate the improvement of our redshift estimates, particularly at z &gt; 1. These new redshifts are available on Zenodo:10.5281/zenodo.8302310 &lt;!--AQ1--&gt; .

Keywords: Surveys, Quasars
Concerning the Verity of the MMRD Relation for Novae. It has long been claimed that novae reaching the highest luminosity at the peak of their eruptions appear to fade the fastest from maximum light. The relationship between peak brightness and fade rate is known as the Maximum-Magnitude, Rate-of-Decline (MMRD) relation. Lightcurve parameters for the most recent sample of M31 recurrent novae are presented and used to buttress the case that the observed MMRD relation can be explained as a consequence of observational selection effects coupled with expectations from standard nova models.

Keywords: Cataclysmic variable stars, Recurrent novae, Novae
Lambda Boo Abundance Characteristics in the T Tauri Star TWA 9A. Abundances in the weak-lined T Tauri star TWA 9A show enhanced volatile and somewhat depleted refractory elements. This resembles a pattern seen in some Herbig AeBe stars.

Keywords: T Tauri stars
Galactic ChitChat: Using Large Language Models to Converse with Astronomy Literature. We demonstrate the potential of the state-of-the-art OpenAI GPT-4 large language model to engage in meaningful interactions with Astronomy papers using in-context prompting. To optimize for efficiency, we employ a distillation technique that effectively reduces the size of the original input paper by 50%, while maintaining the paragraph structure and overall semantic integrity. We then explore the model's responses using a multi-document context (ten distilled documents). Our findings indicate that GPT-4 excels in the multi-document domain, providing detailed answers contextualized within the framework of related research findings. Our results showcase the potential of large language models for the astronomical community, offering a promising avenue for further exploration, particularly the possibility of utilizing the models for hypothesis generation.

Keywords: Galactic archaeology, Galaxy accretion, Milky Way evolution
Ultracool Dwarf Absolute Magnitude versus Spectral Type Relations for JWST NIRCam Filters. We synthesize JWST NIRCam photometry for a range of narrow, medium, and wide filters using SpeX prism spectra and parallaxes of 688 field-age and 151 young (≲200 Myr) ultracool dwarfs (spectral types M6-T9). We derive absolute magnitude-spectral type polynomial relations for the F164N, F187N, and F212N narrow filters; the F140M, F162M, F182M, and F210M medium filters; and the F115W, F150W, and F200W wide filters. Our relations enable the calculation of photometric distances for ultracool dwarfs observed with JWST in the absence of parallax measurements. Additionally, using the synthesized photometry to generate color-color figures can help distinguish high-redshift galaxies from brown dwarf interlopers.

Keywords: Brown dwarfs, Stellar classification, James Webb Space Telescope, Photometry, Absolute magnitude
When were the First Exocontinents?. Earth's biosphere was able to increase as continents emerged. I assess when continents could first appear on hypothetical rocky planets of nearby stars. Radiogenic heating of the planetary mantle is evaluated through stellar abundances of iron and silicon (core and mantle proxies) and thorium and potassium (mantle heating proxies). The heat per unit mantle mass is compared to a threshold on Earth after which large-scale continents appeared. Longer delays are inferred for some exoplanets, particularly those with high thorium, but earliest continents could have arisen 2 Gyr before those on Earth, among thin disk stars. In the thick disk, continents could appear 4-5 Gyr pre-Earth. Hence, subsolar-metalicity systems could be an important focus in searching for planets where life could be more advanced than on Earth. At least ~2 worlds with such old continents are expected to be accessible to future space telescopes, such as Habitable Worlds Observatory.

Keywords: Stellar abundances, Exoplanet plate tectonics, Astrobiology
Comparative Study of Low-temperature Opacities with GARSTEC Models. We present a comparative study of the effect of low-temperature opacities on stellar models up to the Red Giant branch (RGB), computed with the GARching STellar Evolution Code. We have used two sets of low-temperature opacities; ÆSOPUS (Æ) from the University of Padova and those from the Wichita State University group (F05). In the relevant range of temperatures for this study, $\mathrm{log}{\kappa }^{\unicode{x000C6}}$ &lt; $\mathrm{log}{\kappa }^{{\rm{F}}05}$ . Therefore, to compare stellar evolutionary tracks, we performed a solar calibration of the α mlt, for each set of low-temperature opacities. After carrying such a calibration, we find that stellar evolutionary tracks are almost unaffected by the choice of low-temperature opacities, with largest variations of 25-30 K at the latest evolutionary stages of the RGB phase.

Keywords: Astronomy data modeling, Stellar properties, Stellar astronomy, Stellar physics, Hertzsprung Russell diagram, Stellar evolution
The Behavior of Bp He-weak Stars in the Far UV-Paper XIII: HD 161480. The analysis of four spectra of the B7 He-weak star HD 161480 recorded by the SWP camera on board the International Ultraviolet Explorer reveals instances of variations of the far ultraviolet spectral energy distribution shortwards of 1800 Å in spectra collected over 4 consecutive days with identical exposure times. The Si II doublet near 1530 Å is stronger at phase of FUV minimum. The C IV doublet at 1550 Å is absent. These variations suggest that silicon and other chemical elements are probably distributed in an inhomogeneous manner over the surface of HD 161480. The radial velocity of the Si II doublet varies over the 4 days observation, reflecting the orbital motion of this SB1 star.

Keywords: Helium-weak stars, Chemically peculiar stars
Photometric Update of δ Scuti Stars: ZZ Microscopium. Multi-color CCD photometric update of the bright high amplitude δ Scuti star ZZ Microscopium (ZZ Mic) is presented. We find that the B band has the highest amplitude at 0.47 mag while the V band amplitude is smaller at 0.38 mag. The revised pulsation period 0.06717850 day is similar to most recent previous estimates. We did not detect secondary mode pulsations. We find the temperature of the star varies by 720 K during pulsations and its radius changes by 0.1 R ☉. We estimate the mass of ZZ Mic as 1.93 M ☉ and surface gravity g as 4.19.

Keywords: Delta Scuti variable stars
Automatic Detection of Plateau Phases in Light Curves of Variable Stars. Modern astronomical surveys produce millions of light curves of variable sources. These massive data sets challenge the community to create automatic light-curve processing methods for detection, classification, and characterization of variable stars. In this paper, we present a novel method for extracting the variable components of a light curve based on Otsu's thresholding method. To validate the effectiveness of this method, we apply it to the light curves of detached eclipsing binaries and dwarf novae, sourced from Optical Gravitational Lensing Experiment catalogs.

Keywords: Time series analysis
X-Ray and Optical Observations of the Young M Dwarf Dipper Star TIC 234284556. We observed TIC 234284556 in X-rays and in the optical with XMM-Newton to study the recurring dip previously seen in TESS observations. The dip did not appear during our observation. We detect X-ray flares and anti-correlated rotational modulation in X-rays and in the optical.

Keywords: M dwarf stars, Starspots, Stellar flares, Stellar coronae, X-ray stars
Further X-Ray Timing Investigations on the 2 hr Periodicity of PSR J1311-3430. We investigate the 2 hr X-ray periodicity of the black widow system PSR J1311-3430 observed in 2018. In this study, we applied a simulation method to find the period and error, which results in 7400 ± 60 s. The period is slightly shorter and the uncertainty is slightly higher than that reported in De Luca et al. Besides, we performed a phased-resolved spectral analysis, and find that the system did not show significant spectral variability over a cycle.

Keywords: X-ray astronomy, X-ray photometry, High energy astrophysics, Period search , Low-mass x-ray binary stars, Binary pulsars
Evolution of Galaxy Size in the FOGGIE Simulations. Cosmological simulations are a powerful tool to study galaxy evolution as they can span a substantial fraction of the cosmic time. In this research note, we use the Figuring Out Gas and Galaxies In Enzo simulations-cosmological hydrodynamic simulation of Milky Way-like galaxies-to measure the evolution of the radius of the galaxy disk. Additionally, we analyze the simulations along three different lines of sight. Lastly, we show that the disk size increases over time regardless of angle of projection.

Keywords: Hydrodynamical simulations, Galaxy disks, Galaxy evolution, Circumgalactic medium, Milky Way evolution, Milky Way Galaxy
Energetic Superflare from a Young Solar Analog, DS Tucanae A, Observed with NICER. Superflares in young solar analogs serve as proxies to the environment that shaped Earth into a habitable planet. DS Tucanae A is a young (45 Myr) solar analog producing superflares detectable in the X-ray energies and other bands. We detect and characterize a superflare using NICER. We model the peak emission of the superflare and find a temperature of 3.8 ± 0.3 keV, or (43.9 ± 3.5) × 106 K, and emission measure of (1.11 ± 0.03) × 1054 cm-3. We fit the flux values over time to a fast rise, exponential decay model, and find the decay timescale of the flare is τ = (4.9 ± 0.5) × 103 s. The total X-ray energy of the superflare is (2.8 ± 0.1) × 1035 erg. We estimate the loop length L = (6.3 ± 1.0) × 1010 cm2 and coronal magnetic field strength B c = 152 ± 22 G.

Keywords: Solar analogs, Stellar x-ray flares
Instrumental Effects of Lyα Properties in CLASSY and Implication for HETDEX and JWST. In this work, we quantify the effects of spectral resolution (R) on the measured Lyα properties and determine the robustness of Lyα trends measured with different spectrographs. We select 9 galaxies with diverse Lyα properties from the COS Legacy Archive Spectroscopic SurveY and measure the equivalent width and peak velocities of their Lyα profiles from their high-resolution spectra (R ~ 4225-15000). We downgrade these spectra to several lower resolutions (R ~ 800-3500) and re-measure the Lyα properties. Using these values, we derive the systematic errors and investigate the robustness of Lyα properties as a function of spectral resolution. We find that equivalent width can be robustly measured at low R. However, the minimal spectral resolution required to obtain robust measurements of the Lyα peak velocities is R ≳ 2600 (Δv = 115 km s-1).

Keywords: Lyman-alpha galaxies, Galaxy spectroscopy, Ultraviolet spectroscopy, Galaxies
A New Stellar Companion to GJ 835. We present the discovery of a new stellar companion to GJ 835, detected using the Differential Speckle Survey Instrument on the 4.3 m Lowell Discovery Telescope and the Astrophysical Research Consortium 3.5 m telescope at Apache Point Observatory. This new companion joins a known companion in the system, making the system triple. Using 2MASS and Gaia data, as well as our observed properties, we estimate projected separations and spectral types for the three components in the system.

Keywords: M dwarf stars, Solar neighborhood, Low mass stars, High angular resolution
New Abundance Determinations for the B9 Mn Star HD 53929. Analysis of coadded high resolution spectra of the chemically peculiar star HD 53929 recorded by the SWP and LWR cameras on board the International Ultraviolet Explorer yields estimates of the abundances of silicon and manganese, respectively 1.5 and 6 times the solar abundances, in the atmosphere of this star. The synthesis of the 4400-4500 Å range allows the determination of the abundances of helium, magnesium, phosphorus and iron. Compared to solar abundances, helium is very underabundant (0.05 solar), magnesium is also underabundant by a factor of 0.20 times the solar abundances. Phosphorus is overabundant by a factor of 20.

Keywords: Chemically peculiar stars, Manganese stars
A Possible Superbolide Over Don Benito (Spain) in 1926 December 27. We discuss the discovery of a significant meteoric event over Don Benito, Spain, described in two news reports from the regional newspaper "Extremadura." These reports detail intense light, loud noises, and shattered windows in Don Benito during 1926 December. Despite limited information, this research note aims to share the findings with the scientific community for further investigation.

Keywords: Bolides
Fortuitous Observations of Potential Stellar Relay Probe Positions with GBT. Recent theoretical and observational works have investigated the possibility that extraterrestrial intelligence could use the Sun as a gravitational lens in order to aid communication across interstellar distances. Unlike other targeted SETI searches where the drift rate of any artificial extraterrestrial signals may be unknown up to some large upper limit, the drift rates of any solar system relay probes would be known and set only by the motion of the Earth. One recent work used purpose-designed Green Bank Telescope (GBT) observations to search for signals from a hypothetical communications probe several hundred astronomical unit from the Sun at the antipode of the α Centauri AB system. To further aid in the advancement of relay-probe searches, we present a table of 1764 archival GBT observations which fortuitously fall near the positions of hypothetical probes communicating with stars within 100 pc and compute the drift rates for these probes.

Keywords: Technosignatures, Gravitational lensing, Radio astronomy
Variability Census of Legacy Catalogs. I. 1800+ New δ Scuti and γ Doradus Stars. Discovery of 1200+ new δ Scuti and 680+ new γ Doradus stars is presented as the preliminary results of a variability vetting census of the four legacy catalogs: BD, HD, SAO and PPM. This systematic screening of cataloged stars is part of a special survey project that aims to identify bright variable stars based on publicly accessible high-precision space photometry. Identification was performed using a Python program that involved human intervention and visual inspection. Successive results will be reported separately in a dynamic online catalog as the census progresses. *Dedicated to my wife Jingyun Zhang.

Keywords: Gamma Doradus variable stars, Delta Scuti variable stars, Pulsating variable stars
Gnuastro: Simulating the Exposure Map of a Pointing Pattern. The pointing pattern is an integral part of designing one's observation strategy for a certain scientific goal. But accounting for the particular science case or instrument artifacts (like distortion, vignetting or large areas of bad pixels) can make it hard to predict how the exposure map of the final stack will be. To help address this problem, Gnuastro 0.21 includes a new executable program called astscript-pointing-simulate that is fully described in the Gnuastro manual and comes with a complete tutorial. The figures of this research note are reproducible with Maneage, on the Git commit 7597a1a.

Keywords: Astronomy software, Astronomical techniques, Field of view, Direct imaging, Astronomical methods
Direct Measurements of Stellar Masses with the Habitable World Observatory. Background stars within ~1″ of a nearby massive object will have their centroids shift by about 1 mas due to microlensing. This provides mass measurements of stellar mass objects in the solar neighborhood. Habitable Worlds Observatory (HWO) targets toward the Galactic Bulge will have a sufficient density of background stars that HWO will be able to measure their masses independently of stellar evolutionary models, which will allow more accurate habitable histories of their exoplanets to be evaluated. This opportunity is maximized for designs of HWO with very high contrasts (Δmag ≳25) and the capability for precise relative astrometry with respect to the target star. HWO can apply this technique to any nearby stellar mass object in the direction of the Galactic Bulge, enhancing its science case and that of precursor missions like Roman.

Keywords: Astrometric microlensing effect, Microlensing optical depth, Coronagraphic imaging, Stellar masses, Gravitational microlensing
Defining Millisecond Pulsars. Millisecond pulsars (MSP) are an important subclass of rotation powered pulsars (RPP), traditionally defined as those with P  s  &lt; 20-30 ms and B  s  ≲ 1010 G. We re-examine this definition by applying Gaussian mixture model analysis to identify distinct clusters within the RPP population and find that the MSPs appear to be better demarcated by the condition P  s  ≲ 16 ms.

Keywords: Neutron stars, Millisecond pulsars, Pulsars