Sazuna/UAT_keywords huggingface dataset:
E+A Galaxy Candidates in and around the Virgo Cluster. E+A galaxies are post-starburst galaxies that have recently undergone complete quenching of their star formation, making them a valuable source for studying the evolution of galaxies and their environments. Using the Extended Virgo Cluster Catalog, we manually identified 125 "green" and 24 "blue" E+A galaxy candidates within the Virgo Cluster based on their spectral shape, u - r color, lack of Hα emission, and hydrogen Balmer absorption. Interestingly, we found a higher density of E+A galaxy candidates in the Virgo Cluster than that of most other low-redshift clusters, and several regions of particularly high E+A density within the Virgo Cluster. The large number of E+As in and around the Virgo Cluster hints at the influence of a dense galaxy environment on the formation of E+A galaxies, and the potential value of E+A galaxies as a diagnostic tool to study the evolution of clusters.

Keywords: Virgo Cluster, E+A galaxies, Galaxy evolution, Galaxy quenching, Post-starburst galaxies
Dark Matter Halo Masses from Abundance Matching and Kinematics: Tensions for the Milky Way and M31. The dark matter halo masses of galaxies can be estimated from their stellar masses via abundance matching (AM). For both the Milky Way and M31, the AM mass is higher than the mass inferred from kinematics. The higher AM masses exacerbate the missing satellite problem. The difference is especially pronounced for M31, for which ${M}_{200}^{\mathrm{AM}}\gtrsim {10}^{13}\,{M}_{\odot }$ but ${M}_{200}^{\mathrm{kin}}\lt 2\times {10}^{12}\,{M}_{\odot }$ . This is more than expected from scatter in the AM relation, and may suggest the need for separate AM relations for early and late type galaxies.

Keywords: Galaxy dark matter halos, Milky Way dark matter halo
Coadded Spectroscopic Stellar Parameters and Abundances from the LAMOST Low Resolution Survey. I combine duplicate spectroscopic stellar parameter estimates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data Release 6 Low Resolution Spectral Survey A, F, G, and K Type stellar parameter catalog. Combining repeat measurements results in a factor of two improvement in the precision of the spectroscopic stellar parameter estimates. Moreover, this trivializes the process of performing coordinate-based cross-matching with other catalogs. Similarly, I combine duplicate stellar abundance estimates for the Xiang et al. catalog which was produced using LAMOST Data Release 5 Low Resolution Spectral Survey data. These data have numerous applications in stellar, galactic, and exoplanet astronomy. The catalogs I produce are available as machine-readable tables at https://doi.org/10.7281/T1/QISGRU.

Keywords: Sky surveys, Stellar properties, Fundamental parameters of stars, Stellar abundances, Astronomy data analysis, Stellar astronomy
Spectroscopic Confirmation of an M6 Dwarf Companion to the Nearby Star BD-08 2582. We report resolved optical spectroscopy for the nearby low-mass stellar system BD-08 2582AB. We confirm prior unpublished reports of the existence of the secondary, and the spectral data indicate a secondary type of M6 Ve, consistent with spectrophotometric estimates from Gaia astrometry. The secondary exhibits Hα emission at a level equivalent to other M6 dwarfs, and has a metallicity index in line with its well-studied solar-metallicity K7/M0 primary.

Keywords: M dwarf stars, Close binary stars, Solar neighborhood, Stellar activity, Low mass stars
The GN-z11-Flash Event can be a Satellite Glint. Recently Jiang et al. reported the discovery of a possible short duration transient, detected in a single image, spatially associated with a z ∼ 11 galaxy. Jiang et al. and Kann et al. suggested the transient originates from a γ-Ray Burst (GRB), while Padmanabhan &amp; Loeb argued the flash is consistent with a supernova shock breakout event of a 300 M⊙ Population III star. Jiang et al. argued against the possibility that this event originated from light reflected off a satellite. Here we show that reflection of sunlight from a high-orbit satellite or a piece of space debris is a valid and reasonable explanation. As shown in recent works, the rate of point-like satellite reflections, brighter than 11th magnitude, is &gt;10 deg-2 day-1 near the equatorial plane. At higher declinations the rate is 5-50 times lower, but still significant: about four orders of magnitudes higher than the rate estimated for GRBs.

Keywords: Artificial satellites, Gamma-ray bursts, High-redshift galaxies
Transient Terrestrial Trojans: Comparative Short-term Dynamical Evolution of 2010 TK<SUB>7</SUB> and 2020 XL<SUB>5</SUB>. The Trojan asteroids of Mars and Jupiter are long-term stable, those of Earth are expected to be just transient companions. The first Trojan of our planet, 2010 TK7, was discovered in 2010 and its resonant state was found to be transient. Here, we provide a preliminary assessment of the current dynamical status and short-term orbital evolution of 2020 XL5, a recently discovered near-Earth asteroid that might be the second known representative of this elusive population. Our calculations show that the current orbit determination of 2010 TK7 is consistent with that of a robust, present-day, yet transient, L4 Earth Trojan. In sharp contrast, the current orbit determination of 2020 XL5 is still too uncertain and its orbital evolution too chaotic to confirm a current Trojan engagement with Earth, although the nominal orbit shows such a behavior. More observations are required to provide a conclusive answer.

Keywords: Trojan asteroids, Near-Earth objects, Solar system, Asteroids
Constraint on \dot{G}/G from Orbital Timing. Constraints on the variation of the gravitational constant G have been obtained by many observers using different methods, the most reliable and stringent being those based on the orbital timing of bodies in the solar system and binary pulsars. We show that the constraints determined from orbital timing are on $\dot{G}/G-3\dot{c}/c$ rather than on $\dot{G}/G$ when the speed of light c is also considered to be varying. Increasingly tighter constraint on $\dot{G}/G$ from these observations are possibly due to $\dot{G}/G-3\dot{c}/c=0$ . This relationship between G and c was determined in a previous work by fitting the supernovae 1a data using the relativistically covariant cosmological model with varying $c,G$ and cosmological constant Λ.

Keywords: Dirac cosmology
A Multi-band Forced-photometry Catalog in the ELAIS-S1 Field. The ELAIS-S1 field will be an Legacy Survey of Space and Time Deep Drilling field, and it also has extensive multiwavelength coverage. To improve the utility of the existing data, we use The Tractor to perform forced-photometry measurements in this field. We compile data in 16 bands from the DeepDrill, VIDEO, DES, ESIS, and VOICE surveys. Using a priori information from the high-resolution fiducial images in VIDEO, we model the images in other bands and generate a forced-photometry catalog. This technique enables consistency throughout different surveys, deblends sources from low-resolution images, extends photometric measurements to a fainter magnitude regime, and improves photometric-redshift estimates. Our catalog contains over 0.8 million sources covering a 3.4 deg2 area in the VIDEO footprint and is available at 10.5281/zenodo.4540178.

Keywords: Surveys, Galaxy photometry, Catalogs
Eight Blue E+A Galaxy Candidates Located inside a Large-scale Filament in the Coma Cluster. E+A galaxies are post-starburst galaxies that have recently undergone quenching of their star formation, making them a valuable source for studying the evolution of galaxies. Using the SDSS Data Release 16, we found 13 "blue" E+A galaxy candidates and 117 "green" E+A galaxy candidates in and around the Coma cluster of galaxies. Blue E+A galaxies tend to be younger than green E+A galaxies, giving us a picture of how young galaxies transform into E+A galaxies. Based on their positions in R.A./decl./velocity space, we found that 8 of the blue E+A galaxy candidates seem to be located inside a large-scale galactic filament emanating from the center of the Coma Cluster. Their locations suggest there is an unusually high number of E+A galaxies throughout the filament. We have not yet determined whether these E+A galaxy candidates formed through merging or ram pressure stripping.

Keywords: Coma Cluster, E+A galaxies, Sloan photometry, Post-starburst galaxies, Intergalactic filaments
The Correlated Response of the Narrow FeKα Emission Line to the Primary Continuum Changes in the Seyfert Galaxy NGC 2992. The intensely varying Active Galactic nucleus (AGN) NGC 2992, on timescales of days to years, provides us with a unique testbed to study the response of the narrow FeKα emission line to the changes in the primary 2-10 keV AGN continuum. We find a strong correlation between the narrow FeKα line flux and the 2-10 keV flux with a Spearman correlation coefficient s = 0.70 and probability p &lt; 0.001, over a period of ∼20 yr. There is no evidence of such a correlation in &lt;1 yr, but the FeKα flux responds at ∼3 yr timescales, allowing us to put the reprocessor distance scale to 0.3 pc ≤ d ≤ 1 pc, consistent with that of torus reflection. The primary 2-10 keV continuum of NGC 2992 undergoes a high-low-high transition in ∼16 yr (2003-2019). Future long term monitoring will be crucial.

Keywords: X-ray active galactic nuclei, Active galactic nuclei
Close Companions to the T Tauri Stars CVSO 109 and CVSO 165 Observed by the HST ULLYSES Program. The Hubble Space Telescope (HST) Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program is a HST Director's Discretionary program that is in the process of obtaining a large library of ultraviolet spectroscopic observations of young stars of both high and low masses. We present information on close companions to the T Tauri stars CVSO 109 and CVSO 165 in Orion that were observed with the HST as part of this program. CVSO 109 has a fainter companion at an angular separation ρ = 0"64 near PA = 218° and Δ(F28X50LP) ≈ 0.6 mag, while the CVSO 165 companion is at ρ = 0"30 near PA = 326° with Δ(F28X50LP) ≈ 1.7 mag. Both components of CVSO 165 appear to be active stars with strong emission features, while the CVSO 109 companion shows only modest indications of stellar activity. Extracted spectra for each of these components will be included in ULLYSES Data Release 2.

Keywords: T Tauri stars, Binary stars, Companion stars
The Large Far-ultraviolet Flux Deficiency of α Doradus (B8 IIIp Si). The far-UV spectral energy distribution of α Dor recorded by IUE is compared to that of the constant and normal star ζ Dra, which has similar fundamental parameters. α Dor has much less flux than ζ Dra shortwards of 1800 Å, due to the accumulation of very strong absorption lines of Si II, in particular autoionization lines around 1400 Å. Two spectra of α Dor separated by 9 hr (i.e., much less than the rotational period) show evidence of modest variability shortwards of 1800 Å.

Keywords: Bp stars
Citizen ASAS-SN: Citizen Science with The All-Sky Automated Survey for SuperNovae (ASAS-SN). We present "Citizen ASAS-SN," a citizen science project hosted on the Zooniverse platform which utilizes data from the All-Sky Automated Survey for SuperNovae (ASAS-SN). Volunteers are presented with ASAS-SN g-band light curves of variable star candidates. The classification workflow allows volunteers to classify these sources into major variable groups, while also allowing for the identification of unique variable stars for additional follow-up.

Keywords: Stellar classification, Light curves, Variable stars
Uncertainty Propagation in (Gaussian) Convolution. Convolution of spectra, maps, or even higher dimensional data is often part of data reduction or analysis. Often a Gaussian kernel is used. When the convolved data are measurements, they are associated with uncertainties. This research notice derives how uncertainties propagate through the convolution. While the math is straightforward algebra, the results are not readily available. Here, the uncertainty propagation applied to regularly gridded data is provided. The calculation is done for uncorrelated data and correlated data.

Keywords: Astronomy data reduction
Gaia EDR3 Confirms a Red Dwarf Companion of the nearby F1 Star HD 105452 and Reveals a New Brown Dwarf Companion of the M4.5 Dwarf SCR J1214-2345. There are 88 stars which lack colors, but have measured parallaxes in Gaia EDR3 that place them within 20 pc from the Sun. Among them we found two new common parallax and proper motion (CPPM) companions separated from their primaries by about 3″. The CPPM companion of a nearby (d = 14.98 pc) F1 star, HD 105452 B, was already imaged with the Hubble Space Telescope and is now confirmed with Gaia data and photometrically classified by us as M4 dwarf. The other CPPM companion, SCR J1214-2345 B orbiting an M4.5 dwarf at d = 10.77 pc, represents the faintest brown dwarf discovery made by Gaia so far. It was also imaged by the VISTA Hemisphere Survey and partly detected in the near-infrared. Our photometric classification led to an uncertain spectral type of T1 ± 3 and needs to be confirmed by spectroscopic follow-up.

Keywords: Brown dwarfs, Parallax, Binary stars, Solar neighborhood, Proper motions, Stellar distance
Amplitude and Frequency Modulation of Super-Nyquist Frequency from Kepler Photometric Sampling. We present a simulation showing that super-Nyquist frequencies may have periodic amplitude and frequency modulations, even if actually stable, in time series sampled like the Kepler data. These modulations are caused by the barycentric time correction, which destroys the evenly spaced time measurements, making the Nyquist frequency variable over the spacecraft orbit around the Sun. These modulations can easily be identified in pulsating stars from Kepler's photometric data.

Keywords: Pulsation frequency method, Pulsating variable stars
Colors of Jupiter Trojan Dynamical Families as Measured by the Zwicky Transient Facility. We use data from the first two years of the public survey of the Zwicky Transient Facility to analyze colors of proposed Jupiter Trojan asteroid families. The well studied Eurybates cluster remains the only family with a significant number of color measurements, and we find that the average colors of this family are less red than typical Jupiter Trojans, in agreement with smaller studies. The limited number of objects detected in this and other surveys for the other families makes their colors continue to be uncertain.

Keywords: Jupiter trojans, Asteroid surfaces
A Spectroscopic Survey of Superthin Galaxies. We present spectroscopic observations of superthin galaxies. Superthin galaxies have the thinnest stellar disks among disk galaxies. A sample of 138 superthins was observed in visible light with the 3.5 m telescope at Apache Point Observatory in New Mexico to obtain the rotation curves of the ionized gas in the galaxies. The sample represents the largest survey of superthin galaxies so far and provides a database to investigate the kinematic and dynamic properties of this special type of extragalactic objects. Here we present the rotation curves of our sample objects.

Keywords: Galaxy dynamics, Galaxy kinematics, Extragalactic astronomy, Galaxy rotation curves, Galaxy spectroscopy, Dark matter
A Stationary Drake Equation Distribution as a Balance of Birth-death Processes. Previous critiques of the Drake Equation have highlighted its deterministic nature, implying that the number of civilizations is the same at all times. Here, I build upon earlier work and present a stochastic formulation. The birth of civilizations within the galaxy is modeled as following a uniform rate (Poisson) stochastic process, with a mean rate of λC. Each then experiences a constant hazard rate of collapse, which defines an exponential distribution with rate parameter λL. Thus, the galaxy is viewed as a frothing landscape of civilization birth and collapse. Under these assumptions, I show that N in the Drake Equation must follow another Poisson distribution, with a mean rate (λC/λL). This is used to demonstrate why the Copernican Principle does not allow one to infer N, as well evaluating the algebraic probability of being alone in the galaxy.

Keywords: Search for extraterrestrial intelligence
Merging Things Together: Merger Pair Analysis from the IllustrisTNG Simulation Suite. Expanding on the work of Snyder et al., we present merger pair analysis of mock surveys from the IllustrisTNG suite of 3D cosmological simulations. Our results, shown in the context of previous work with Illustris-1, are consistent with a flattening of the pair fraction curve at a redshift of z = 2.

Keywords: Extragalactic astronomy, Galaxy mergers, Astronomical simulations
The First Fast Radio Burst Detected with VLITE-Fast. The VLITE-Fast experiment combines the wide-field-of-view of single dish antennas operating at low frequency with the high angular resolution furnished by the 3-30 km baselines of the VLA, making it ideal for the detection and precise localization of radio transients. We describe the VLITE-Fast experiment, its capabilities, and operational status, and we briefly overview its main science case, the detection of fast radio bursts (FRBs) and determination of their host galaxies. We report on commissioning observations in an incoherent mode prohibiting precise localization. These include discovery of FRB 20200405A, detected during early science operations at dispersion measure (DM) = 212.3 pc cm-3, strongly in excess of the Galactic DM along the line of sight.

Keywords: Radio transient sources
Infrared Spectroscopy of YZ Reticuli (Nova Reticuli 2020). IR spectroscopy from three epochs is presented for the very bright, X-ray nova YZ Reticuli (Nova Reticuli 2020). The first spectrum, from 2.5 months after outburst, shows a nova well into the coronal phase, with strong lines of [Si VI] and [Si VII], and with little or no interstellar reddening, and no dust emission. The second spectrum, from one month later, shows a four-fold drop in brightness and a measurable increase in the coronal lines relative to the lower excitation features. The final spectrum, from 7 months post outburst, is a factor of six fainter and shows a decrease in the relative strength of the coronal lines from the previous epoch. Emission lines from O I and [N I] are present at all epochs, indicating the persistence of a region of largely neutral gas in this otherwise high excitation object.

Keywords: Novae
Spectroscopy of the 2015 Outburst of AG Pegasi. Between 2015 September and 2016 January, we obtained 18 spectra of the 2015 classical outburst of AG Pegasi—a symbiotic star consisting of a white dwarf (WD), red giant, and surrounding nebula. Modelling the flux contributions of these components reveals that nebular emission, from the reprocessing of high energy WD photons, dominates the 3200-6300 Å range. Nebular emission rises and falls in line with changes seen in the WD, whose properties have been derived using Hβ and He II (4686 A) line flux, and emission measure calculations. WD parameters follow changes seen in visual band light curves. During the second peak of the outburst, WD temperatures reach 166,000 ± 6000 K, with a luminosity and radius of 14,000 ± 2000 L⊙ and 0.149 ± 0.014 R⊙ respectively. These features are consistent with an expansion of the WD pseudo-photosphere due to an accretion rate exceeding that required for stable hydrogen burning.

Keywords: Time domain astronomy, Symbiotic binary stars, Symbiotic novae, Transient sources
Leave No Low-mass Star Behind: Results from Extended Surveys of Hα Emission from Stars in Praesepe and the Hyades. We present the results of our spectroscopic surveys of members of two nearby, rich open clusters, Praesepe and the Hyades, which fold in updated membership catalogs for both based on Gaia data. Our data include 1200 of our own R ≈ 2000 spectra (900 for Praesepe, 300 for the Hyades), 300 archival spectra (270 for Praesepe, 30 for the Hyades), and more than 1000 spectra obtained by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (750 for Praesepe and 440 for the Hyades). For each good-quality spectrum, we measure the Hα equivalent width and run a Monte Carlo iterator to estimate the uncertainty. Our surveys include at least one spectrum for 870 stars in Praesepe and for 460 stars in the Hyades. The vast majority of these are stars later than F7 (&lt;1.2 M⊙). Our coverage extends down to a spectral type of M6 (≈0.2 M⊙) in both clusters, allowing us to compare in detail the equivalent-width distributions for these two coeval populations (≈800 Myr). Our surveys represent the most extensive investigations of Hα emission in single-aged low-mass stellar populations to date, and form the basis of our exploration of the age-rotation-activity in these two benchmark clusters. * This work is based on observations obtained at the MDM Observatory, operated by Dartmouth College, Columbia University, Ohio State University, Ohio University, and the University of Michigan.

Keywords: Surveys, Open star clusters, Low mass stars, Stellar activity
TESS Re-observes the Young Multi-planet System TOI-451: Refined Ephemeris and Activity Evolution. We present a new analysis of the light curve of the young planet-hosting star TOI 451 in the light of new observations from TESS Cycle 3. Our joint analysis of the transits of all three planets, using all available TESS data, results in an improved ephemeris for TOI 451 b and TOI 451 c, which will help to plan follow-up observations. The updated mid-transit times are BJD-2,457,000 = ${1410.9896}_{-0.0029}^{+0.0032}$ , ${1411.7982}_{-0.0020}^{+0.0022}$ , and ${1416.63407}_{-0.00100}^{+0.00096}$ for TOI 451 b, c, and d, respectively, and the periods are ${1.8587028}_{-10e-06}^{+08e-06}$ , ${9.192453}_{-3.3e-05}^{+4.1e-05}$ , and ${16.364932}_{-3.5e-05}^{+3.6e-05}$ days. We also model the out-of-transit light curve using a Gaussian Process with a quasi-periodic kernel, and infer a change in the properties of the active regions on the surface of TOI 451 between TESS Cycles 1 and 3.

Keywords: Transits, Exoplanets, Stellar activity
These are not the Stars You are Looking for: On the Detection of X-Ray Emission from HD 143352. As part of a search for X-ray emission from RV Tau variable stars, we discovered a serendipitous X-ray detection of the closest RV Tau variable star, HD 143352. X-rays were detected in the 0.2-2.0 keV energy band, with most counts detected in the 0.5-1.0 keV band. The emission is consistent with a 106 K plasma and LX ∼ 2 × 1028 erg s-1. This would be the second RV Tau star detected in X-ray emission. However, after estimating the temperature (Teff ∼ 6000 K) and bolometric luminosity (Lbol ∼ 4L⊙) from the spectral energy distribution, we place HD 143352 on the main sequence. These stellar parameters suggest HD 143352 is neither an RV Tau variable nor a post-asymptotic giant branch star nor a super giant, but rather an early F-type main sequence star. The X-ray emission detected from HD 143352 is consistent with coronal-like emission with LX/Lbol ∼ 10-6.

Keywords: Henry Draper catalog, Stellar activity, Stellar classification, X-ray surveys, DC stars, F stars, RV Tauri variable stars
E+A Galaxy Candidates in and around the Leo Cluster. E+A galaxies are post-starburst galaxies that have undergone a recent, complete quenching of star formation. We have analyzed a color-constrained sample of galaxies from the Sloan Digital Sky Survey within a 77'5 radius of the center of the Leo cluster of galaxies (A1367; J2000 11:44:36.5 + 19:45:32) within 3000 km s-1 of Leo's redshift of z = 0.022 to identify and survey the E+A galaxy candidates in the cluster. Within this sample, we classified 52 of these galaxies as E+A galaxy candidates based on their spectral shapes, u-r color, lack of Hα emission, and higher-order hydrogen Balmer absorption. We further subdivide this group into "blue" and "green" E+A candidates. Our results show that the E+A galaxy candidates are distributed across the northwest and southeast subclusters of Leo, possibly as a result of merging between the two subclusters.

Keywords: E+A galaxies, Galaxy evolution, Galaxy quenching, Abell clusters, Post-starburst galaxies