Sazuna/UAT_keywords huggingface dataset:
Gaia RR Lyrae Stars in Nearby Ultra-faint Dwarf Satellite Galaxies. We search for RR Lyrae stars (RRLs) in 27 nearby (&lt;100 kpc) ultra-faint dwarf satellite galaxies using the Gaia DR2 catalog of RRLs. Based on proper motions, magnitudes, and location on the sky, we associate 47 Gaia RRLs with 14 different satellites. Distances based on RRLs are provided for those galaxies. We have identified RRLs for the first time in the Tucana II dwarf galaxy, and find additional members in Ursa Major II, Coma Berenices, Hydrus I, Bootes I, and Bootes III. In addition we have identified candidate extra-tidal RRLs in six galaxies, which suggests they may be undergoing tidal disruption. We found 10 galaxies have no RRLs either in Gaia or in the literature. However, given the known completeness of Gaia DR2 we cannot conclude these galaxies indeed lack variable stars of this type.

Keywords: Local Group, Galaxy distances, Dwarf galaxies, Distance indicators, RR Lyrae variable stars
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. I. The Most Energetic Outflows in the Universe and Other Discoveries. The Hubble Space Telescope/Cosmic Origins Spectrograph (COS) has opened a new discovery space for studying quasar absorption outflows and their contribution to active galactic nucleus (AGN) feedback. Specifically, COS provides high-quality far-ultraviolet (FUV) spectra covering the diagnostic-rich 500-1050 Å rest frame (hereafter, EUV500) of medium redshift objects. The quality and quantity of EUV500 diagnostic troughs allow us to probe the very high-ionization phase, which carries 90% or more of the outflowing material, as well as to determine the distance of most outflows from the central source (R). The first objective is impossible to achieve with ground-based spectra, and R can be measured in only ∼1% of them. Here, we summarize the main results of the first dedicated survey of such outflows, including the following.

Keywords: Quasar absorption line spectroscopy, Broad-absorption line quasar, Quasars, Active galaxies, Active galactic nuclei
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. II. The Most Energetic Quasar Outflow Measured to Date. We present a study of the BAL outflows seen in quasar SDSS J1042+1646 (z = 0.978) in the rest-frame 500-1050 Å (EUV500) region. The results are based on the analysis of recent Hubble Space Telescope/Cosmic Origins Spectrograph observations. Five outflow systems are identified, where, in total, they include ∼70 outflow troughs from ionic transitions. These include the first non-solar detections from transitions of O V*, Ne V*, Ar VI, Ca VI, Ca VII, and Ca VIII. The appearance of very high-ionization species (e.g., Ne VIII, Na IX, and Mg X) in all outflows necessitates at least two ionization phases for the observed outflows. We develop an interactive Synthetic Spectral Simulation method to fit the multitude of observed troughs. Detections of density sensitive troughs (e.g., S IV* λ661.40 Å and the O V* multiplet) allow us to determine the distance of the outflows (R) as well as their energetics. Two of the outflows are at R ≃ 800 pc and one is at R ≃ 15 pc. One of the outflows has the highest kinetic luminosity on record (\dot{E}_{k} = 5 × 1046 erg s-1), which is 20% of its Eddington luminosity. Such a large ratio suggests that this outflow can provide the energy needed for active galactic nucleus feedback mechanisms.

Keywords: Quasar absorption line spectroscopy, Broad-absorption line quasar, Quasars, Active galaxies, Active galactic nuclei
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. III. Four Similar Outflows in 2MASS J1051+1247 with Enough Energy to Be Major Contributors to AGN Feedback. We detect four very energetic outflows in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra of quasar 2MASS J1051+1247 with a combined kinetic luminosity (\dot{E}_{K}) of 1046 erg s-1. Remarkable similarities are seen in these outflows: velocity centroids between 4900 and 5700 km s-1, distances from the central source (R) of a few hundred parsecs that are all consistent within the errors, and an \dot{E}_{K} within a factor of two for all outflows. Hence, a common origin for the outflows is probable. Most of the outflowing mass resides in a very high-ionization phase evident by troughs from Ne VIII, Na IX, Mg X, and Si XII, which connect the physical conditions of these ultraviolet outflows to the X-ray warm absorber outflows seen in nearby Seyfert galaxies. Three of the outflows have two or three independent diagnostics for the electron number density, yielding consistent values for each outflow, which increase the robustness of the R determinations. Troughs from never-before-seen ionic transitions of Ar VI, O IV*, Ne VI*, and Ne V* are identified. With a combined \dot{E}_{K} that is 7.0-2.3+6.5% of the quasar's Eddington luminosity, these outflows are prime candidates to be major agents for various active galactic nuclei feedback effects.

Keywords: AGN host galaxies, Quasar absorption line spectroscopy, Broad-absorption line quasar, Quasars, Active galaxies, Active galactic nuclei
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. IV. The Largest Broad Absorption Line Acceleration. We present an analysis of the broad absorption line (BAL) velocity shift that appeared in one of the outflow systems in quasar SDSS J1042+1646. Observations were taken by the Hubble Space Telescope/Cosmic Origins Spectrograph in 2011 and 2017 in the 500-1050 Å rest frame. The outflow's velocity centroid shifted by ∼-1550 km s-1 from -19,500 km s-1 to -21,050 km s-1 over a rest-frame time of 3.2 yr. The velocity shift signatures are most apparent in the absorption features from the Ne VIII λλ770.41 and 780.32 doublet and are supported by the absorption troughs from O V λ629.73 and the Mg X λλ609.79 and 624.94 doublet. This is the first time where a quasar outflow velocity shift is observed in troughs from more than one ion and in distinct troughs from a doublet transition (Ne VIII). We attribute the velocity shift to an acceleration of an existing outflow as we are able to exclude photoionization changes and motion of material into and out of the line of sight as alternate explanations. This leads to an average acceleration of 480 km s-1 yr-1 (1.52 cm s-2) in the quasar rest frame. Both the acceleration and the absolute velocity shift are the largest reported for a quasar outflow to date. Based on the absorption troughs of the O V* multiplet, we derive a range for the distance of the outflow (R) from the central source, 0.05 pc &lt; R &lt; 54.3 pc. This outflow shows similarities with the fast X-ray outflow detected in quasar PG 1211+143. We use the acceleration and velocity shift to constrain radiatively accelerated active galactic nucleus disk-wind models and use them to make predictions for future observations.

Keywords: Quasar absorption line spectroscopy, Quasars, Active galaxies, Active galactic nuclei, Broad band photometry
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. V. Richness of Physical Diagnostics and Ionization Potential-dependent Velocity Shift in PKS J0352-0711. We analyze absorption troughs from two outflows within PKS J0352-0711 (S1 at -1950 km s-1 and S2 at -3150 km s-1) from spectra taken with Hubble Space Telescope/Cosmic Origins Spectrograph, which cover the diagnostic-rich 585-900 Å rest-frame wavelength range. In S2, for the first time we clearly detect absorption troughs from Ca IV, Ca V, Ca V*, Ca VII*, and Ca VIII*. The column density measurement of Ca V suggests S2 has a super-solar metallicity. Both outflows require at least two ionization phases where the column density of the very high-ionization phase is roughly 15 times larger than the corresponding high-ionization phase. These high column densities and very high-ionization potential ions are similar to X-ray warm absorbers. The two phases of S2 show a unique velocity centroid shift between associated troughs. Through Monte Carlo measurements of the O V* absorption troughs, we determine the electron number density of S2 (fully corroborated by independent measurements from the Ca VII* and Ca VIIi* troughs), yielding a distance of 9 pc and a kinetic luminosity of 2 × 1043 erg s-1. S1 is located farther away at 500 pc from the central source with a kinetic luminosity of 1043 erg s-1.

Keywords: AGN host galaxies, Quasar absorption line spectroscopy, Quasars, Broad-absorption line quasar, Active galaxies, Active galactic nuclei
HST/COS Observations of Quasar Outflows in the 500-1050 Å Rest Frame. VI. Wide, Energetic Outflows in SDSS J0755+2306. We present the analysis of two outflows (S1 at -5500 km s-1 and S2 at -9700 km s-1) seen in recent Hubble Space Telescope/Cosmic Origins Spectrograph observations of quasar SDSS J0755+2306 (z = 0.854). The outflows are detected as absorption troughs from both high-ionization species, including N III, O III, and S IV, and very high-ionization species, including Ar VIII, Ne VIII, and Na IX. The derived photoionization solutions show that each outflow requires a two ionization-phase solution. For S1, troughs from S IV* and S IV allow us to derive an electron number density, ne = 1.8 × 104 cm-3, and its distance from the central source of R = 270 pc. For S2, troughs from O III* and O III yield ne = 1.2 × 103 cm-3 and R = 1600 pc. The kinetic luminosity of S2 is &gt;12% of the Eddington luminosity for the quasar and, therefore, can provide strong AGN feedback effects. Comparison of absorption troughs from O III and O VI in both outflow systems supports the idea that for a given element, higher-ionization ions have larger covering fractions than lower-ionization ones.

Keywords: Broad-absorption line quasar, Active galactic nuclei, Quasar absorption line spectroscopy, Quasars
Structure of Brightest Cluster Galaxies and Intracluster Light. Observations of 170 local (z ≲ 0.08) galaxy clusters in the northern hemisphere have been obtained with the Wendelstein Telescope Wide Field Imager (WWFI). We correct for systematic effects such as point-spread function broadening, foreground star contamination, relative bias offsets, and charge persistence. Background inhomogeneities induced by scattered light are reduced down to ΔSB &gt; 31 g' mag arcsec-2 by large dithering and subtraction of night-sky flats. Residual background inhomogeneities brighter than SBσ &lt; 27.6 g' mag arcsec-2 caused by galactic cirrus are detected in front of 23% of the clusters. However, the large field of view allows discrimination between accretion signatures and galactic cirrus. We detect accretion signatures in the form of tidal streams in 22%, shells in 9.4%, and multiple nuclei in 47% of the brightest cluster galaxies (BCGs) and find two BCGs in 7% of the clusters. We measure semimajor-axis surface brightness profiles of the BCGs and their surrounding intracluster light (ICL) down to a limiting surface brightness of SB = 30 g' mag arcsec-2. The spatial resolution in the inner regions is increased by combining the WWFI light profiles with those that we measured from archival Hubble Space Telescope images or deconvolved WWFI images. We find that 71% of the BCG+ICL systems have surface brightness (SB) profiles that are well described by a single Sérsic function, whereas 29% require a double Sérsic function to obtain a good fit. We find that BCGs have scaling relations that differ markedly from those of normal ellipticals, likely due to their indistinguishable embedding in the ICL.

Keywords: Galaxy formation, cD galaxies, Scaling relations, Galaxy stellar halos, Surface photometry, Brightest cluster galaxies
Long-period High-amplitude Red Variables in the KELT Survey. We present a sample of 4132 Mira-like variables (red variables with long periods and high amplitudes) in the Kilodegree Extremely Little Telescope (KELT) survey. Of these, 376 are new Mira-like detections. We used Two Micron All Sky Survey (2MASS) colors to identify candidate asymptotic giant branch stars. We searched for photometric variability among the candidate asymptotic giant branch stars and identified stars that show periodic variability. We selected variables with high amplitudes and strong periodic behavior using a Random Forest classifier. Of the sample of 4132 Mira-like variables, we estimate that 70% are Miras and 30% are semiregular (SR) variables. We also adopt the method of using (WRP-WK_s) versus (J-{Ks) colors in distinguishing between O-rich and C-rich Miras and find it to be an improvement over 2MASS colors.

Keywords: Mira variable stars, Long period variable stars, Time series analysis
YZiCS: Unveiling the Quenching History of Cluster Galaxies Using Phase-space Analysis. We used the time since infall (TSI) of galaxies, obtained from the Yonsei Zoom-in Cluster Simulation, and the star formation rate (SFR) from the Sloan Digital Sky Survey Data Release 10 to study how quickly the star formation of disk galaxies is quenched in cluster environments. We first confirm that both simulated and observed galaxies are consistently distributed in phase space. We then hypothesize that the TSI and SFR are causally connected; thus, both the TSI and SFR of galaxies at each position of phase space can be associated through abundance matching. Using a flexible model, we derive the star formation history (SFH) of cluster galaxies that best reproduces the relationship between the TSI and SFR at z ∼ 0.08. According to this SFH, we find that galaxies with M* &gt; 109.5 M⊙ generally follow the so-called "delayed-then-rapid" quenching pattern. Our main results are as follows: (I) part of the quenching takes place outside clusters through mass quenching and preprocessing. The e-folding timescale of this "ex situ quenching phase" is roughly 3 Gyr with a strong inverse mass dependence. (II) The pace of quenching is maintained roughly for 2 Gyr ("delay time") during the first crossing time into the cluster. During the delay time, quenching remains gentle, probably because gas loss happens primarily on hot and neutral gases. (III) Quenching becomes more dramatic (e-folding timescale of roughly 1 Gyr) after delay time, probably because ram pressure stripping is strongest near the cluster center. Counterintuitively, more massive galaxies show shorter quenching timescales mainly because they enter their clusters with lower gas fractions due to ex situ quenching.

Keywords: Galaxy evolution
One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field. We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities, and stellar masses of 100 UDGs distributed in an area of ∼330 deg2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low surface brightness galaxies.

Keywords: Stellar ages, Stellar populations, Stellar masses, Metallicity, Low surface brightness galaxies
AstroSat UVIT Survey of M31: Point-source Catalog. An ultraviolet survey of M31 has been carried out during 2017-19 with the UltraViolet Imaging Telescope (UVIT) instrument on board the AstroSat Observatory. Here we analyze far- and near-ultraviolet (FUV and NUV) observations from the M31 UVIT survey, which covers a sky area of ≃3° × 1° with spatial resolution of ≃1″. The observations included six filter bands in the wavelength range of 120-280 nm. The limiting magnitude (AB) in the FUV band (CaF2 filter), which has the largest number of detected sources, is ∼23. The primary product of this work is the M31 UVIT point-source catalog containing positions and photometry. In total ≃75,000 sources were detected at FUV or NUV wavelengths.

Keywords: Ultraviolet astronomy, Ultraviolet sources, Andromeda Galaxy
Modeling Dense Star Clusters in the Milky Way and Beyond with the CMC Cluster Catalog. We present a set of 148 independent N-body simulations of globular clusters (GCs) computed using the code CMC (Cluster Monte Carlo). At an age of ∼10-13 Gyr, the resulting models cover nearly the full range of cluster properties exhibited by the Milky Way GCs, including total mass, core and half-light radii, metallicity, and galactocentric distance. We use our models to investigate the role that stellar-mass black holes play in the process of core collapse. Furthermore, we study how dynamical interactions affect the formation and evolution of several important types of sources in GCs, including low-mass X-ray binaries, millisecond pulsars, blue stragglers, cataclysmic variables, Type Ia supernovae, calcium-rich transients, and merging compact binaries. While our focus here is on old, low-metallicity GCs, our CMC simulations follow the evolution of clusters over a Hubble time, and they include a wide range of metallicities (up to solar), so that our results can also be used to study younger and higher-metallicity star clusters. Finally, the output from these simulations is available for download at https://cmc.ciera.northwestern.edu/home/.

Keywords: Globular star clusters, X-ray binary stars, Binary stars, Stellar mass black holes, Stellar dynamics, Computational methods, Blue straggler stars, Cataclysmic variable stars
Multicolor Optical Monitoring of the Blazar S5 0716+714 from 2017 to 2019. We continuously monitored the blazar S5 0716+714 in the optical g, r, and I bands from 2017 November 10 to 2019 June 6. The total number of observations is 201 nights including 26,973 data points. This is a very large quasi-simultaneous multicolor sample for the blazar. The average time spans and time resolutions are 3.4 hr and 2.9 minutes per night, respectively. During the period of observations, the target source in the r band brightens from 14.16m to 12.29m together with five prominent subflares, and then becomes fainter to 14.76m, and again brightens to 12.94m with seven prominent subflares. For the long-term variations, we find a strong flatter-when-brighter (FWB) trend at a low-flux state and then a weak FWB trend at a higher-flux state. A weak FWB trend at a low-flux state and then a strong FWB trend at a higher-flux state are also reported. Most subflares show strong FWB trends, except for two flares with a weak FWB trend. The particle acceleration and cooling mechanisms together with the superposition of the different FWB slopes from the subflares likely explain the optical color behaviors. A scenario of bent jet is discussed.

Keywords: Active galactic nuclei, Galaxy photometry, BL Lacertae objects, Galaxy jets
Physical Parameters of Late-type Contact Binaries in the Northern Catalina Sky Survey. We present the physical parameters of 2335 late-type contact binary (CB) systems extracted from the Catalina Sky Survey (CSS). Our sample was selected from the CSS Data Release 1 by strictly limiting the prevailing temperature uncertainties and light-curve fitting residuals, allowing us to almost eliminate any possible contaminants. We developed an automatic Wilson-Devinney-type code to derive the relative properties of CBs based on their light-curve morphology. By adopting the distances derived from CB (orbital) period-luminosity relations (PLRs), combined with the well-defined mass-luminosity relation for the systems' primary stars and assuming solar metallicity, we calculated the objects' masses, radii, and luminosities. Our sample of fully eclipsing CBs contains 1530 W-, 710 A-, and 95 B-type CBs. A comparison with literature data and with the results from different surveys confirms the accuracy and coherence of our measurements. The period distributions of the various CB subtypes are different, hinting at a possible evolutionary sequence. W-type CBs are clearly located in a strip in the total mass versus mass-ratio plane, while A-type CBs may exhibit a slightly different dependence. There are no significant differences among the PLRs of A- and W-type CBs, but the PLR zero-points are affected by their mass ratios and fill-out factors. Determination of zero-point differences for different types of CBs may help us improve the accuracy of the resulting PLRs. We demonstrate that automated approaches to deriving CB properties could be a powerful tool for application to the much larger CB samples expected to result from future surveys.

Keywords: Fundamental parameters of stars, Astronomy data analysis, Contact binary stars
The Gravitational Instability of Adiabatic Filaments. Filamentary structures, or long and narrow streams of material, arise in many areas of astronomy. Here we investigate the stability of such filaments by performing an eigenmode analysis of adiabatic and polytropic fluid cylinders, which are the cylindrical analog of spherical polytropes. We show that these cylinders are gravitationally unstable to perturbations along the axis of the cylinder below a critical wavenumber kcrit ≃ few, where kcrit is measured relative to the radius of the cylinder. Below this critical wavenumber, perturbations grow as ∝ eσuτ, where τ is time relative to the sound-crossing time across the diameter of the cylinder, and we derive the growth rate σu as a function of wavenumber. We find that there is a maximum growth rate σmax ∼ 1 that occurs at a specific wavenumber kmax ∼ 1, and we derive the growth rate σmax and the wavenumbers kmax and kcrit for a range of adiabatic indices. To the extent that filamentary structures can be approximated as adiabatic and fluidlike, our results imply that these filaments are unstable without the need to appeal to magnetic fields or external media. Further, the objects that condense out of the instability of such filaments are separated by a preferred length scale, form over a preferred timescale, and possess a preferred mass scale.

Keywords: Analytical mathematics, Gravitational instability, Hydrodynamics
Relativistic MR-MP Energy Levels for K-like Fe. Relativistic Multi-Reference Møller-Plesset (MR-MP) many-body perturbation theory calculations are reported for the ground and excited states of Fe VIII. Energies are provided for states coming from the configurations 3sm3pn3dp4lq (l = s, p, d, and f) with m+n+p+q=9, p ≤ 3, and q ≤ 1. The MR-MP results were compared with the recommended observed values in the CHIANTI-v8 database and with previous ab-initio calculations. The MR-MP calculations reproduce 90% of the available observed values within 3500 cm-1. The previous accurate ab-initio calculations reproduce only 50% of the observed values within 3500 cm-1. The electronic structure of Fe VIII is very complex and our MR-MP results show that accurate calculations require the inclusion of not only 3s2-3d2, 3p2-3d2, and 3s3p-3d2 promotions but also of all electron correlations via perturbation theory.

Keywords: Atomic spectroscopy, Line positions, Atomic data benchmarking, Atomic physics