Sazuna/UAT_keywords huggingface dataset:
A Chromatic Treatment of Linear Polarization in the Solar Corona at the 2023 Total Solar Eclipse. The broadband solar K-corona is linearly polarized due to Thomson scattering. Various strategies have been used to represent coronal polarization. Here, we present a new way to visualize the polarized corona, using observations from the 2023 April 20 total solar eclipse in Australia in support of the Citizen CATE 2024 project. We convert observations in the common four-polarizer orthogonal basis (0°, 45°, 90°, &amp; 135°) to -60°, 0°, and +60° (MZP) polarization, which is homologous to R, G, B color channels. The unique image generated provides some sense of how humans might visualize polarization if we could perceive it in the same way we perceive color.

Keywords: Solar eclipses, Solar K corona, Solar corona, Polarimetry
Predicting the UV Escape Fraction of the First Galaxies in the Renaissance Simulations with Machine Learning. Cosmic reionization is likely driven by UV starlight emanating from the first generations of galaxies. A galaxy's UV escape fraction, or the fraction of photons escaping from the galaxy, is useful to quantify its contribution to reionization. However, the UV escape fraction is notoriously difficult to predict due to local environment dependency and variability over time. Using data from the Renaissance Simulations, we attempt to make predictions about the impact of the first stars and galaxies on their environments. We present a time-independent classification model using a general artificial neural network architecture to predict the UV escape fraction given other galaxy properties-namely halo mass, stellar mass, redshift, star formation rate, lookback time, and gas fraction. We find our validation accuracy to be approximately 50%-65%, depending on the data set size from each zoom-in region of the Renaissance Simulations.

Keywords: Galaxy formation, High-redshift galaxies, Reionization
The Discovery of 63 Giant Radio Galaxies in the FIRST Survey. Giant Radio Galaxies (GRGs) are Active Galactic Nuclei with radio emission that extends over projected sizes &gt;0.7 Mpc. The large angular sizes associated with GRGs complicate their identification in radio survey images using traditional source finders. In this Note, we use DRAGNHUNTER, an algorithm designed to find double-lobed radio galaxies, to search for GRGs in the Faint Images of the Radio Sky at Twenty cm survey. Radio and optical images of identified candidates are visually inspected to confirm their authenticity, resulting in the discovery of 63 previously unreported GRGs.

Keywords: Extragalactic radio sources, Active galactic nuclei, Radio galaxies, Giant radio galaxies
Late Type Stars in the Michigan Spectral Catalogue: Conflation of Luminosity Classes IV and V. While computing a comprehensive set of mean values and uncertainties for key stellar parameters, particularly absolute V magnitudes and (B - V)0 colors, for main sequence stars drawn from the Michigan Spectral Catalogue (MSC), we discovered a significant co-mingling between luminosity classes IV and V in spectral types G8 and later. Indeed, among the ~200 nearby K0 dwarfs examined, as many 20% may be misclassified subgiants. We present data to substantiate this view and offer some commentary on the observed conflation of these two luminosity classes. We conclude that while the MSC is a unique and largely reliable database for spectral classifications of predominantly southern hemisphere HD stars across the H-R diagram, it does contain some ambiguities in the assignment of luminosity classes IV and V among the late G and early K stars of which users should be aware.

Keywords: Hertzsprung Russell diagram, K dwarf stars, K subgiant stars
Hidden Companions to Intermediate-mass Stars. XIV. Discovery of a 1.8 M <SUB>⊙</SUB>, 0.3 au Companion to Ascella = Zeta Sagittarii A. Zeta Sagittarii is a nearby intermediate mass 13.2 au visual binary. Here we report on a VLTI/GRAVITY interferometric observation that revealed that ζ Sgr is actually a rather compact triple system: the visual primary Ascella (A) is a close equal mass ρ = 10.9 mas ↔ 0.3 au binary. Through isochrone fitting we find masses M Aa = 1.83M ⊙, M Ab = 1.81M ⊙ and M B = 2.03M ⊙. The hierarchy of the triple is low enough to allow for possibly interesting dynamical effects and its ultimate outcome will be a double or triple white dwarf system. We estimate that about 1 Myr ago ζ Sgr passed within a minimum distance of the Sun of 11 pc, rather than 3 pc as previously reported. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Optical interferometry, Multiple stars, A stars
The 23.01 Release of Cloudy. We announce the C23.01 update of CLOUDY. This corrects a simple coding error, present since ~1990, in one routine that required a conversion from the line-center to the mean normalization of the Lyα optical depth. This affects the destruction of H I Lyα by background opacities. Its largest effect is upon the Lyα intensity in high-ionization dusty clouds, where the predicted intensity is now up to three times stronger. Other properties that depend on Lyα destruction, such as grain infrared emission, change in response.

Keywords: Computational methods, Active galaxies, Astronomy software, Atomic physics
The Behavior of the Bp Stars in the Far UV-Paper VII: HD 22316. The analysis of seven spectra of the B9 Cr Hg Si star HD 22316 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal any variations of the far ultraviolet spectral energy distribution shortwards of 1800 Å in spectra collected over 2 yr with identical exposure times. The low excitation line at 1363.45 Å and the resonance line of Cl I at 1379.53 Å are most likely present. Several lines of Al II, Si II, P II but none of S I could be found at their expected wavelengths. The synthesis of several Al II lines consistently yields a clear underabundance of aluminum of about 0.40 times the solar aluminum abundance.

Keywords: Bp stars, Chemically peculiar stars
Stellar Masses and Star Formation Rates of Galaxies and AGNs in the eFEDS GAMA09 Field. The eFEDS is a wide ≈140 deg2 field that has extensive multiwavelength coverage. To improve the utility of the existing data, we use CIGALE to fit source Spectral Energy Distributions (SEDs) from X-rays to far-infrared (FIR) mainly to derive stellar masses (M ⋆) and star-formation rates (SFRs) for normal galaxies and X-ray Active Galactic Nuclei (AGNs). The catalog consists of 2,057,027 galaxies and 10,373 X-ray AGNs located in the ≈60 deg2 GAMA09 sub-field. Comparing our M ⋆ with other available catalogs and our SFRs with FIR-derived SFRs, we demonstrate the general reliability of our SED-fitting measurements. Our catalog is publicly available in Zenodo.

Keywords: Celestial objects catalogs, Active galactic nuclei, Sky surveys, Galaxies
Second-generation Fragments of a Comet Split in the Making: The Liller Family Comets. Kreutz sungrazers and Kracht, Marsden, and Meyer sunskirters are regarded as second- or third-generation fragments of split comets. First-generation fragments have been observed to form, for example, in the cases of comets 73P/Schwassmann-Wachmann 3, D/1993 F2 (Shoemaker-Levy 9), and 332P/Ikeya-Murakami. Here, we compare relevant orbital correlation properties (the distributions of mutual nodal distances, and the angular separation of perihelia and poles) of the Liller family comets-C/1988 A1 (Liller), C/1996 Q1 (Tabur), C/2015 F3 (SWAN), C/2019 Y1 (ATLAS), and C/2023 V5 (Leonard)-with those of fragments of 332P and some Kreutz sungrazers to show that they are first-generation cometary fragments in the process of producing the second-generation.

Keywords: Comets
A Dark Siren Measurement of the Hubble Constant with the LIGO/Virgo Gravitational Wave Event GW190412 and DESI Galaxies. We present a measurement of the Hubble Constant H 0 using the gravitational wave event GW190412, an asymmetric binary black hole merger detected by LIGO/Virgo, as a dark standard siren. This event does not have an electromagnetic counterpart, so we use the statistical standard siren method and marginalize over potential host galaxies from the Dark Energy Spectroscopic Instrument (DESI) survey. GW190412 is well-localized to 12 deg2 (90% credible interval), so it is promising for a dark siren analysis. The dark siren value for ${H}_{0}={85.4}_{-33.9}^{+29.1}$ km s-1 Mpc-1, with a posterior shape that is consistent with redshift overdensities. When combined with the bright standard siren measurement from GW170817 we recover ${H}_{0}={77.96}_{-5.03}^{+23.0}$ km s-1 Mpc-1, consistent with both early and late-time Universe measurements of H 0. This work represents the first standard siren analysis performed with DESI data, and includes the most complete spectroscopic sample used in a dark siren analysis to date.

Keywords: Cosmology, Cosmological parameters, Observational cosmology, Gravitational wave astronomy, Hubble constant, Gravitational waves
The Secondary Maximum of T CrB Caused by Irradiation of the Red Giant by a Cooling White Dwarf. Both the 1866 and 1946 outbursts of the recurrent symbiotic nova T CrB have displayed a mysterious secondary maximum peaking in brightness ~5 months past the primary one. Common to all previous modeling attempts was the rejection of plain irradiation of the red giant (RG), on the basis that the secondary maximum of T CrB would have been out of phase with the transit at superior conjunction of the RG. Implicit to this line of reasoning is the assumption of a constant temperature for the white dwarf (WD) irradiating the RG. I show by radiative modeling that irradiation of the RG by a cooling WD nicely reproduces the photometric evolution of the secondary maximum, both in terms of brightness and color, removes the phasing offset, and provides a straightforward explanation that will be easy to test at the next and imminent outburst.

Keywords: White dwarf stars, Symbiotic novae, Recurrent novae, Red giant stars, Symbiotic binary stars
Testing the Limits of Biosignature Detection in Ca-sulphate Mixtures Through a Simulated Martian Environment. Mixtures of cyanobacterial microbial mat and Ca-sulphate minerals were exposed to a simulated Martian environment via the Thales Alenia Space's "MARSBalloon" Project in partnership with St Bernard's High School via the Orbyts science inclusivity program. FTIR spectroscopic analyses identified that at 50% Ca-sulphate, most microbial mat biosignatures were obscured under Earth conditions, except for the C-O stretch and polysaccharide O-H vibrational modes. At 75% Ca-sulphate concentrations, no spectral biosignatures were observed. However, after exposure to a simulated stratospheric Martian environment, partial dehydration of the Ca-sulphate occurred to reveal the spectral biosignatures. This has implications in the search for life on Mars, particularly within evaporite-rich environments similar to those being investigated by the Curiosity rover.

Keywords: Infrared spectroscopy, Mars, Solar system terrestrial planets, Astrobiology, Spectroscopy, Stratosphere, Biosignatures
Photometric Classification of Evolved Massive Stars: Spectroscopic Verification and Validation. Dorn-Wallenstein et al. utilized a novel machine-learning technique to classify a large sample of evolved massive stars. This resulted in new classifications for ~2550 objects. We wish to validate the efficiency of the Dorn-Wallenstein et al. machine classifier. To this end we obtained new observations of four stars identified by Dorn-Wallenstein et al., with a focus on verifying newly identified emission-line objects and evolved supergiants. We identified a previously unconfirmed Be star, TYC 3740-1791-1, using these data. We assigned spectral types to the two stars in our sample with sufficient signal-to-noise data. We then used Gaia DR3 BP/RP spectra to validate an additional 73 stars from Dorn-Wallenstein et al. Our classifications support the completeness and contamination reported by the authors and confirm the validity of using machine learning-based classification methods on massive stars in the era of big data.

Keywords: B stars, OB stars, Stellar classification, Spectroscopy, Late-type supergiant stars, Be stars, Gaia
Discovery of a Candidate Young Stellar Object in a Citizen Science Search for Compact Nebulae. We report the serendipitous discovery of a bipolar nebula in a citizen science search for non-stellar emission line objects using online sky surveys. It is associated with an infrared (IR) source and is situated next to a dark cloud, seen in emission in the far-IR (FIR). Evidence for an extinction gradient across the object has been found, pointing to close-by dust. This supports the notion that the newly found source is a young stellar object (YSO). It shows an enhanced surface brightness in the r-band, which covers the main emission lines typical for Herbig–Haro objects (HHOs). For an estimated distance of 1.7 kpc, an optical to FIR luminosity of ≳18.5 L ⊙ was derived.

Keywords: Young stellar objects, Star formation, Sky surveys
Pulsational Velocity Variations of the Radial Mode sdBV Star BPM 36430. Hot subdwarf B stars are core-helium burning objects that were once red giants stripped of their outer H envelopes due to binary interactions. Many exhibit pulsations that can be used to determine fundamental stellar parameters like mass and radius. High-cadence TESS photometry of the sdB star BPM 36430 revealed it to be a hybrid-mode pulsator showing several g-mode pulsations and a single strong p-mode oscillation. The latter is likely a radial mode oscillation, given its period (342 s) and high photometric amplitude (2%). Using time-series spectroscopy from the Goodman spectrograph on the 4.1 m SOAR telescope, we detect a sinusoidal radial velocity variation with a semi-amplitude of 4.4 ± 0.4 km s-1 and period consistent with photometry of the p-mode oscillation. This detection provides further evidence the 342 s mode is radial in nature, and that the Baade-Wesselink method can be used with additional observations to constrain the stellar mass and radius.

Keywords: Radial pulsations, Stellar pulsations, B subdwarf stars, Extreme horizontal branch stars, Radial velocity
Limits on the Detection of an Ultra-short-period Planet in the TOI-539 System. Characterized by their close proximity to their host stars and scorching surface temperatures, hot super-Earths represent a readily accessible population that can be used to study the atmospheres, surfaces, and formation of rocky exoplanets in great detail. We present our radial velocity (RV) data analysis for the star TOI-539, in search of the transiting ultra-short-period hot super-Earth planet candidate TOI-539.01 detected by the Transiting Exoplanet Survey Satellite mission. We constrain the planetary mass of TOI-539.01 at the 2.3σ level. Additionally, we perform injection-recovery tests to determine mass detection limits for potential planets in the RV data set. We suggest an intensive RV campaign with higher precision observations to obtain a precise mass measurement and confirmation of TOI-539.01.

Keywords: Radial velocity, Transit photometry, Exoplanets
Citizen Science Discovery of a Recurrently Active Jupiter-Family Comet: (551023) 2012 UQ192. We have discovered evidence of cometary activity originating from (551023) 2012 UQ192 (alternately designated 2019 SN40), which we dynamically classify as a Jupiter Family Comet (JFC). JFCs have eccentric Jupiter-crossing orbits and originate in the Kuiper Belt. Analysis of these objects can provide vital information about minor planets in the outer solar system, such as the distribution of volatiles within the solar system. Activity on 2012 UQ192 was first recognized by volunteers on our NASA Partner Citizen Science project Active Asteroids. Through our own examination of archival image data, we found a total of ~30 images presenting strong evidence of activity near perihelion during two separate orbits. 2012 UQ192 is notable as we found it to be recurrently active. When 2012 UQ192 approaches its perihelion passage in 2027 September, we predict it will reactivate and will be a prime subject for follow-up observations.

Keywords: Asteroids, Comet tails, Short period comets, Comet dynamics, Astronomy data analysis
On the Chromaticity of the (NEO)WISE Astrometry. The Wide-field Infrared Survey Explorer and its follow-up Near-Earth Object (NEO) mission scan the mid-infrared sky twice a year. The spatial and temporal coverage of the resulting database is of utmost importance for variability studies, in particular of young stellar objects which have red W1 ‑ W2 colors. During such an effort, I noticed subarcsecond position offsets between subsequent visits. The offsets do not appear for targets with small W1 ‑ W2 colors, which points to a chromatic origin in the optics, caused by the spacecraft pointing alternating "forward" and "backward" from one visit to another. It amounts to 0.″1 for targets with W1 ‑ W2 ≈ 2. Consideration of this chromatic offset will improve astrometry. This is of particular importance for NEOs that are generally red.

Keywords: Near-Earth objects, Young stellar objects, Sky surveys, Astrometry
The Behavior of Bp He-weak Stars in the Far UV-Paper XIV: HD 143699. The analysis of seven spectra of the B6 He-weak star HD 143699 recorded by the SWP camera on board the International Ultraviolet Explorer reveals variations of the far ultraviolet spectral energy distribution shortwards of 1600 Å in spectra collected from 1994 April 12 to July 9. These variations do not seem to reflect rotational modulation. They could be caused by pulsation with the recently derived pulsation period close to 4 hr. The resonance line of Si II at 1526.71 Å clearly shows an interstellar component. There is no evidence of C IV absorption at 1550 Å in any of the spectra.

Keywords: Helium-weak stars, Chemically peculiar stars
Using Mg II Doublet to Predict the Lyman Continuum Escape Fraction from 14 HETDEX Galaxies. Indirect diagnostics of Lyman continuum (LyC) escape are needed to constrain which sources reionized the universe. We used Mg II to predict the LyC escape fraction ( ${f}_{\mathrm{esc}}^{\mathrm{LyC}}$ ) in 14 galaxies selected from the Hobby-Eberly Telescope Dark Energy Experiment solely based upon their Mg II properties. Using the Low Resolution Spectrograph on HET, we identified 7 and 5 possible LyC leakers depending on the method, with ${f}_{\mathrm{esc}}^{\mathrm{LyC}}$ ranging from 3% to 80%. Interestingly, our targets display diverse [O III]/[O II] ratios (O32), with strong inferred LyC candidates showing lower O32 values than previous confirmed LyC leaker samples. Additionally, a correlation between dust and ${f}_{\mathrm{esc}}^{\mathrm{LyC}}$ was identified. Upcoming Hubble Space Telescope/Cosmic Origins Spectrograph LyC observations of our sample will test if Mg II and dust are predictors of ${f}_{\mathrm{esc}}^{\mathrm{LyC}}$ , providing insights for future JWST studies of high-redshift galaxies.

Keywords: Starburst galaxies, Reionization, Galaxies
Soft X-Ray Excess from Shocked Black Hole Accretion. A certain class of luminous galaxies hosting supermassive black holes (BHs) is known to exhibit an excess of "soft X-rays" in their X-ray spectra. However, its physical identity and origin are yet to be understood. In this work, we systematically study a sample of 9 well-documented narrow-line Seyfert 1 active galactic nuclei by utilizing the archival XMM-Newton/EPIC spectra in the context of general relativistic magnetohydrodynamic model. In this scenario, thermal accretion disk photons (in UV) are Compton up-scattered by nonthermal energetic electrons in the hot downstream accretion due to shock compression, producing the observed soft excess. Our spectral model consists primarily of the shock Comptonization component and the underlying continuum including reflection from the accretion disk. Based on χ 2-statistics, we successfully constrain the model parameters, most notably electron energy of the downstream flow kT  e , effective disk blackbody temperature kT bb, and inclination angle θ for a given BH spin. The disk temperature is commonly found to be kT bb 10 eV and the electron energy ranges from kT  e  75-160 keV (for Schwarzschild BHs) to 126-232 keV (for Kerr BHs) depending on inclination. Our analyses imply that the characteristics of the observed soft excess are strongly dependent on the properties of the downstream accretion flow and BH spin.

Keywords: X-ray astronomy, Active galactic nuclei, X-ray active galactic nuclei
New Pulsating Variable Stars and Eclipsing Binaries in NGC 6871. Leveraging publicly available Transiting Exoplanet Survey Satellite data, I conducted a small regional survey centered on the δ Scuti star V1821 Cyg in the open cluster NGC 6871, spanning a radius of 1°. This survey yielded a remarkable 1530 newly classified variable stars, encompassing: 198 eclipsing binary systems, 12 of which exhibit pulsating or rotating components, 105 γ Doradus stars, 116 δ Scuti stars, 526 rotating variable stars, and dozens of other types. It is not surprising that no RR Lyrae stars were found in this particular young open cluster. *Dedicated to my wife Jingyun Zhang.

Keywords: Eclipsing binary stars, Gamma Doradus variable stars, Delta Scuti variable stars, Pulsating variable stars
Activity in Centaur-like Jupiter-family Comet 2023 RN<SUB>3</SUB>. We present multi-filter observations of Centaur-like Jupiter-family comet 2023 RN3 conducted as part of the Las Cumbres Observatory Outbursting Objects Key Project, as well as analysis of archival data in which 2023 RN3 was expected to be present. We find clear evidence of comet-like mass loss in the form of an extended morphology on UT 2023 November 16 and 18, and an increase in intrinsic brightness of &gt;4 mag between 2022 September and 2023 November. We also report broadband colors for the coma of $g^{\prime} -r^{\prime} =0.61\pm 0.03$ , $r^{\prime} -i^{\prime} =0.30\pm 0.03$ , and $i^{\prime} -z^{\prime} =0.04\pm 0.08$ , giving a $g^{\prime} r^{\prime} i^{\prime} $ spectral slope of $S^{\prime} =(12\pm 2) \% $ /100 nm.

Keywords: Observational astronomy, Optical observation, Sky surveys, Centaur group, Small Solar System bodies, Comae, Short period comets, Comets
HD 110067 is a Wide Hierarchical Triple System. We report that HD 110067, the recently announced host star of a resonant sextuplet of transiting sub-Neptunes, is not a single star as claimed in the discovery paper, but a wide hierarchical triple. The K0 V planet hosting star (V = 8.4 mag, d = 32 pc) has a companion at a wide projected separation of 13,400 au. This companion, namely HD 110106, is a slightly fainter (V = 8.8 mag) K3 V type 8 yr period double-lined spectroscopic binary. The secondary in this spectroscopic binary is contributing a significant amount of flux and has a measured high mass ratio.

Keywords: Exoplanets, Orbital resonances, Planet hosting stars, Mini Neptunes, Trinary stars
Discovery of a Large and Faint Nebula at the Triangulum Galaxy. We report the discovery of a previously uncatalogued arch-shaped filamentary nebula at the outer part of the Triangulum galaxy (M33) centered at α = 1h34m25s, $\delta =+30^\circ 20^{\prime} 17^{\prime\prime} $ (ICRS). This discovery stems from meticulous observations employing deep exposures of M33, using both Hα and [O III] narrow-band filters. The nebula, designated as Roig1 Prades Sky, exhibits an Hα surface brightness of $23.9\,\mathrm{mag}\,{\mathrm{arcsec}}^{-2}$ . Its sky projected location is 21' away from the M33 galactic center toward the southeast direction with an extent of (120 × 440) ± 30 pc. Deep spectroscopic observations are required to unveil its real nature.

Keywords: Optical astronomy, H alpha photometry, Astrophotography, Nebulae