Sazuna/UAT_keywords huggingface dataset:
The Quadruple Image Configurations of Asymptotically Circular Gravitational Lenses. The quadruple image configurations of gravitational lenses with vanishing ellipticity are examined. Even though such lenses asymptotically approach circularity, the configurations are stable if the position of the source relative to the vanishing diamond caustic is held constant. The configurations are the solutions of a quartic equation, an "asymptotically circular lens equation," parameterized by a single complex quantity. Several alternative parameterizations are examined. Relative magnifications of the images are derived. When a nonvanishing quadrupole, in the form of an external shear (XS), is added to the singular isothermal sphere (SIS), its configurations emerge naturally as stretched and squeezed versions of the circular configurations. And as the SIS+XS model is a good first approximation for most quadruply lensed quasars, their configurations likewise have only 2 + 1 salient dimensions. The asymptotically circular configurations can easily be adapted to the problem of solar system "occultation flashes."

Keywords: Critical curve, Strong gravitational lensing, Caustic curve, Gravitational lensing
BD+47 378: An Eclipsing Binary Containing a δ Sct Pulsating Star. New high-resolution spectra of the eclipsing binary BD+47 378 were obtained on five nights between 2020 and 2021 with the Bohyunsan Observatory Echelle Spectrograph in Korea. We collected the TESS light curve of the system obtained from Sectors 17 to 18, which shows a flat bottom at the secondary eclipse, an O'Connell effect, and oscillation features. From the spectral analysis, the radial velocities (RVs) of the primary and secondary stars were obtained, and the temperature of the brighter and more massive primary component was determined to be 7140 ± 100 K. According to a simultaneous analysis of the double-lined RVs and TESS light curves, the masses and radii of both components are M 1 = 1.69 ± 0.03 M ⊙, M 2 = 0.80 ± 0.02 M ⊙, R 1 = 2.01 ± 0.01 R ⊙, and R 2 = 0.79 ± 0.01 R ⊙, respectively. The primary component of the system is located on the δ Sct and γ Dor instability strips. After subtracting the theoretical light curve from the TESS data, a total of four independent frequencies (5.7235 day-1, 6.2577 day-1, 6.9588 day-1, and 14.7675 day-1) were detected using the multiple frequency analysis. These frequencies are typical of a δ Sct pulsator. The results reveal that BD+47 378 is a detached system consisting of two main-sequence stars with a δ Sct type primary component.

Keywords: Fundamental parameters of stars, Multi-periodic pulsation, Spectroscopy, Eclipsing binary stars, Stellar oscillations, Asteroseismology, Stellar evolution
Kiloparsec-scale Radio Structure in z   0.25 Radio-quiet QSOs. We present analysis of a homogeneous, optically selected, volume-limited (0.2 &lt; z &lt; 0.3) sample of 128 radio-quiet quasi-stellar objects (QSOs) recently observed at 6 GHz with the Very Large Array (VLA) in A configuration (~0.″33 resolution). We compare these new results to earlier (2010-2011) 6 GHz observations with the VLA in C configuration (~3.″5). While all of these radio-quiet QSOs (RQQs) were unresolved on a 3.″5 scale (~14 kpc at z = 0.25), we resolve notable complex subgalactic structures in about half of the RQQs at 0.″33 resolution (~1.3 kpc at z = 0.25). By comparison of flux density measurements between the two sets of observations, we demonstrate that significant sub-galactic-scale radio structure is present in at least 70% of the RQQ population and that the central component accounts for an average of ≈65% of the total detected radio power. One RQQ, J0935+4819, shows striking symmetric, double-lobed morphology and appears to be the first identified example of a radio-quiet QSO with FR II type morphology on ~arcsec scale (projected size of ≳6 kpc). In addition to revealing RQQ subgalactic morphology, we employ counterparts from legacy (FIRST at 1.4 GHz) and recent (VLA Sky Survey at 3 GHz) VLA surveys to investigate radio spectral indices and potential variability over decades-long timescales for a subset of the RQQs and for the cores of radio-intermediate and radio-loud sources in the parent sample of 178 QSOs. These results support the growing notion that the RQQ population is not a monolithic phenomenon but instead consists of a mixture of mainly starburst-powered and jet-powered galaxies.

Keywords: Direct imaging, Active galaxies, Radio quiet quasars
Simulating Spectral Kurtosis Mitigation against Realistic Radio Frequency Interference Signals. We investigate the effectiveness of the statistical radio frequency interference (RFI) mitigation technique spectral kurtosis ( $\widehat{{SK}}$ ) in the face of simulated realistic RFI signals. $\widehat{{SK}}\,$ estimates the kurtosis of a collection of M power values in a single channel and provides a detection metric that is able to discern between human-made RFI and incoherent astronomical signals of interest. We test the ability of $\widehat{{SK}}\,$ to flag signals with various representative modulation types, data rates, duty cycles, and carrier frequencies. We flag with various accumulation lengths M and implement multiscale $\widehat{{SK}}$ , which combines information from adjacent time-frequency bins to mitigate weaknesses in single-scale $\widehat{{SK}}$ . We find that signals with significant sidelobe emission from high data rates are harder to flag, as well as signals with a 50% effective duty cycle and weak signal-to-noise ratios. Multiscale $\widehat{{SK}}$ with at least one extra channel can detect both the center channel and sideband interference, flagging greater than 90% as long as the bin channel width is wider in frequency than the RFI.

Keywords: Computational methods, Astronomical instrumentation, Astronomical methods, Astronomical simulations
Tentative Evidence for Water Vapor in the Atmosphere of the Neptune-sized Exoplanet HD 106315c. We present a transmission spectrum for the Neptune-sized exoplanet HD 106315c from optical to infrared wavelengths based on transit observations from the Hubble Space Telescope/Wide Field Camera 3, K2, and Spitzer. The spectrum shows tentative evidence for a water absorption feature in the 1.1-1.7 μm wavelength range with a small amplitude of 30 ppm (corresponding to just 0.8 ± 0.04 atmospheric scale heights). Based on an atmospheric retrieval analysis, the presence of water vapor is tentatively favored with a Bayes factor of 1.7-2.6 (depending on prior assumptions). The spectrum is most consistent with either an enhanced metallicity or high-altitude condensates, or both. Cloud-free solar composition atmospheres are ruled out at &gt;5σ confidence. We compare the spectrum to grids of cloudy and hazy forward models and find that the spectrum is fit well by models with moderate cloud lofting or haze formation efficiency over a wide range of metallicities (1-100× solar). We combine the constraints on the envelope composition with an interior structure model and estimate that the core mass fraction is ≳0.3. With a bulk composition reminiscent of that of Neptune and an orbital distance of 0.15 au, HD 106315c hints that planets may form out of broadly similar material and arrive at vastly different orbits later in their evolution.

Keywords: Water vapor, Atmospheric clouds, Exoplanets, Hot Neptunes, Exoplanet atmospheres
A Novel Survey for Young Substellar Objects with the W-band Filter. V. IC 348 and Barnard 5 in the Perseus Cloud. We report the discovery of substellar objects in the young star cluster IC 348 and the neighboring Barnard 5 dark cloud, both at the eastern end of the Perseus star-forming complex. The substellar candidates are selected using narrowband imaging, i.e., on and off photometric technique with a filter centered around the water absorption feature at 1.45 μm, a technique proven to be efficient in detecting water-bearing substellar objects. Our spectroscopic observations confirm three brown dwarfs in IC 348. In addition, the source WBIS 03492858+3258064, reported in this work, is the first confirmed brown dwarf discovered toward Barnard 5. Together with the young stellar population selected via near- and mid-infrared colors using the Two Micron All Sky Survey and the Wide-field Infrared Survey Explorer, we diagnose the relation between stellar versus substellar objects with the associated molecular clouds. Analyzed by Gaia EDR3 parallaxes and kinematics of the cloud members across the Perseus region, we propose the star formation scenario of the complex under influence of the nearby OB association.

Keywords: Open star clusters, Star forming regions, Brown dwarfs, Young stellar objects
White Dwarf Binaries across the H-R Diagram. We created the APOGEE-GALEX-Gaia catalog to study white dwarf (WD) binaries. This database aims to create a minimally biased sample of WD binary systems identified from a combination of GALEX, Gaia, and APOGEE data to increase the number of WD binaries with orbital parameters and chemical compositions. We identify 3414 sources as WD binary candidates, with nondegenerate companions of spectral types between F and M, including main-sequence stars, main-sequence binaries, subgiants, sub-subgiants, red giants, and red clump stars. Among our findings are (a) a total of 1806 systems having inferred WD radii R &lt; 25 R ⊕, which constitute a more reliable group of WD binary candidates within the main sample; (b) a difference in the metallicity distribution function between WD binary candidates and the control sample of most luminous giants (M  H  &lt; -3.0); (c) the existence of a population of sub-subgiants with WD companions; (d) evidence for shorter periods in binaries that contain WDs compared to those that do not, as shown by the cumulative distributions of APOGEE radial velocity shifts; (e) evidence for systemic orbital evolution in a sample of 252 WD binaries with orbital periods, based on differences in the period distribution between systems with red clump, main-sequence binary, and sub-subgiant companions and systems with main-sequence or red giant companions; and (f) evidence for chemical enrichment during common envelope (CE) evolution, shown by lower metallicities in wide WD binary candidates (P &gt; 100 days) compared to post-CE (P &lt; 100 days) WD binary candidates.

Keywords: Surveys, White dwarf stars, Binary stars
SDSS-IV MaNGA: The MaNGA Dwarf Galaxy Sample Presentation. We present the MaNGA Dwarf galaxy (MaNDala) Value Added Catalog (VAC), from the final release of the Sloan Digital Sky Survey-IV program. MaNDala consists of 136 randomly selected bright dwarf galaxies with M * &lt; 109.1 M ⊙ and M  g  &gt; -18.5, making it the largest integral field spectroscopy homogeneous sample of dwarf galaxies. We release a photometric analysis of the g, r, and z broadband imaging based on the DESI Legacy Imaging Surveys, as well as a spectroscopic analysis based on the Pipe3D SDSS-IV VAC. Our release includes the surface brightness (SB), geometric parameters, and color profiles, Sérsic fits as well as stellar population properties (such as stellar ages, metallicities, and star formation histories), and emission lines' fluxes within the FOV and the effective radii of the galaxies. We find that the majority of the MaNDala galaxies are star-forming late-type galaxies with &lt;n Sersic,r&gt; ~ 1.6 that are centrals (central/satellite dichotomy). MaNDala covers a large range of SB values (we find 11 candidate ultra-diffuse galaxies and three compact ones), filling the gap between classical dwarfs and low-mass galaxies in the Kormendy Diagram and in the size-mass/luminosity relation, which seems to flatten at 108 &lt; M */M ⊙ &lt; 109 with &lt;R  e,r &gt; ~ 2.7 kpc. A large fraction of MaNDala galaxies formed from an early low-metallicity burst of SF, but also from late SF events from more metal-enriched gas: half of the MaNDala galaxies assembled 50% of their mass at &lt;z&gt; &gt; 2, while the last 20% was at &lt;z&gt; &lt; 0.3. Finally, a bending of the sSFR-M * relation at M * ~ 109 M ⊙ for the main-sequence galaxies seems to be supported by MaNDala.

Keywords: Dwarf galaxies
Shear Measurement with Poorly Resolved Images. Weak lensing studies typically require excellent seeing conditions for the purpose of maximizing the number density of well-resolved galaxy images. It is interesting to ask to what extent the seeing size limits the usefulness of the astronomical images in weak lensing. In this work, we study this issue with the data of the DECam Legacy Survey, which is a part of the target selection program for the Dark Energy Spectroscopic Instrument. Using the Fourier_Quad shear measurement pipeline, we demonstrate that images with relatively poor seeing conditions (~1.″5) can still yield accurate shear estimators. We do not find any correlation between systematic shear error and the image resolution.

Keywords: Weak gravitational lensing, Gravitational lensing shear, Gravitational lensing
Tracers of Dense Gas in the Outer Galaxy. We have mapped $\mathrm{HCN}$ and HCO+ (J = 1 → 0) line emission toward a sample of seven star-forming regions (with $12+\mathrm{log}[{\rm{O}}/{\rm{H}}]$ ranging from 8.34 to 8.69) in the outer Milky Way (Galactocentric distance &gt;9.5 kpc), using the 14 m radio telescope of the Taeduk Radio Astronomy Observatory. We compare these two molecular lines with other conventional tracers of dense gas, millimeter-wave continuum emission from dust and extinction thresholds (A V ≥ 8 mag), inferred from the 13CO line data. $\mathrm{HCN}$ and HCO+ correlate better with the millimeter emission than with the extinction criterion. A significant amount of luminosity comes from regions below the extinction criterion and outside the millimeter clump for all the clouds. The average fraction of $\mathrm{HCN}$ luminosity from within the regions with A V ≥ 8 mag is 0.343 ± 0.225; for the regions of millimeter emission, it is 0.478 ± 0.149. Based on a comparison with column density maps from Herschel, $\mathrm{HCN}$ and HCO+ trace dense gas in high column density regions better than does 13CO. HCO+ is less concentrated than $\mathrm{HCN}$ for outer Galaxy targets, in contrast with the inner Galaxy sample, suggesting that metallicity may affect the interpretation of tracers of dense gas. The conversion factor between the dense gas mass (M dense) and line luminosities of $\mathrm{HCN}$ and HCO+, when integrated over the whole cloud, is comparable to factors used in extragalactic studies.

Keywords: Star forming regions, Molecular clouds
System Architecture and Planetary Obliquity: Implications for Long-term Habitability. In the search for life beyond our solar system, attention should be focused on those planets that have the potential to maintain habitable conditions over the prolonged periods of time needed for the emergence and expansion of life as we know it. The observable planetary architecture is one of the determinants for long-term habitability as it controls the orbital evolution and ultimately the stellar fluxes received by the planet. With an ensemble of n-body simulations and obliquity models of hypothetical planetary systems, we demonstrate that the amplitude and period of the eccentricity, obliquity, and precession cycles of an Earth-like planet are sensitive to the orbital characteristics of a giant companion planet. A series of transient, ocean-coupled climate simulations show how these characteristics of astronomical cycles are decisive for the evolving surface conditions and long-term fractional habitability relative to the modern Earth. The habitability of Earth-like planets increases with the eccentricity of a Jupiter-like companion, provided that the mean obliquity is sufficiently low to maintain temperate temperatures over large parts of its surface throughout the orbital year. A giant companion closer in results in shorter eccentricity cycles of an Earth-like planet but longer, high-amplitude, obliquity cycles. The period and amplitude of obliquity cycles can be estimated to first order from the orbital pathways calculated by the n-body simulations. In the majority of simulations, the obliquity amplitude relates directly to the orbital inclination whereas the period of the obliquity cycle is a function of the nodal precession and the proximity of the giant companion.

Keywords: Exoplanet dynamics, Orbital evolution, Astrobiology, Planetary climates, Habitable planets
The Rapid Rotation of the Strongly Magnetic Ultramassive White Dwarf EGGR 156. The distribution of white dwarf rotation periods provides a means for constraining angular momentum evolution during the late stages of stellar evolution, as well as insight into the physics and remnants of double degenerate mergers. Although the rotational distribution of low-mass white dwarfs is relatively well constrained via asteroseismology, that of high-mass white dwarfs, which can arise from either intermediate-mass stellar evolution or white dwarf mergers, is not. Photometric variability in white dwarfs due to rotation of a spotted star is rapidly increasing the sample size of high-mass white dwarfs with measured rotation periods. We present the discovery of 22.4 minute photometric variability in the light curve of EGGR 156, a strongly magnetic, ultramassive white dwarf. We interpret this variability as rapid rotation, and our data suggest that EGGR 156 is the remnant of a double degenerate merger. Finally, we calculate the rate of period change in rapidly-rotating, massive, magnetic WDs due to magnetic dipole radiation. In many cases, including EGGR 156, the period change is not currently detectable over reasonable timescales, indicating that these WDs could be very precise clocks. For the most highly-magnetic, rapidly-rotating massive WDs, such as ZTF J1901+1450 and RE J0317-853, the period change should be detectable and may help constrain the structure and evolution of these exotic white dwarfs.

Keywords: Stellar mergers, White dwarf stars, Radiative braking, Magnetic variable stars, Stellar rotation
Revisit of Open Clusters UPK 39, UPK 41, and PHOC 39: A New Binary Open Cluster Found. We investigate the three open clusters near the Aquila Rift cloud, named UPK 39 (c1 hereafter), UPK 41 (c2 hereafter) in Sim et al. (2019), and PHOC 39 (c3 hereafter) in Hunt &amp; Reffert (2021). Using photometric passpands, reddening, and extinction from Gaia DR3, we construct the color-absolute-magnitude diagram. Using isochrone fits, their ages are estimated as 6.3 ± 0.9, 8.1 ± 1.4 and 21.8 ± 2.2 Myr. Their proper motions and radial velocities, estimated using data from Gaia and LAMOST, are very similar. From their orbits, relative distances among them at different times, kinematics, ages, and metallicities, we conclude that c1 and c2 are primordial binary open cluster, which are likely to have been formed at the same time, and c3 may capture c1, c2 in the future.

Keywords: Stellar kinematics, Open star clusters
On the Accuracy of Three-dimensional Kinematic Distances. Over the past decade, the BeSSeL Survey and the VERA project have measured trigonometric parallaxes to ≈250 massive, young stars using VLBI techniques. These sources trace spiral arms over nearly half of the Milky Way. What is now needed are accurate distances to such stars that are well past the Galactic center. Here we analyze the potential for addressing this need by combining line-of-sight velocities and proper motions to yield three-dimenensional (3D) kinematic distance estimates. For sources within about 10 kpc of the Sun, significant systematic uncertainties can occur, and trigonometric parallaxes are generally superior. However, for sources well past the Galactic center, 3D kinematic distances are robust and more accurate than can usually be achieved by trigonometic parallaxes.

Keywords: Milky Way rotation, Distance indicators, Astrometry, Astrophysical masers, Astronomical methods
ACCESS: Confirmation of a Clear Atmosphere for WASP-96b and a Comparison of Light Curve Detrending Techniques. One of the strongest Na I features was observed in WASP-96b. To confirm this novel detection, we provide a new 475-825 nm transmission spectrum obtained with Magellan/IMACS, which indeed confirms the presence of a broad sodium absorption feature. We find the same result when reanalyzing the 400-825 nm VLT/FORS2 data. We also utilize synthetic data to test the effectiveness of two common detrending techniques: (1) a Gaussian processes (GP) routine, and (2) common-mode correction followed by polynomial correction (CMC+Poly). We find that both methods poorly reproduce the absolute transit depths but maintain their true spectral shape. This emphasizes the importance of fitting for offsets when combining spectra from different sources or epochs. Additionally, we find that, for our data sets, both methods give consistent results, but CMC+Poly is more accurate and precise. We combine the Magellan/IMACS and VLT/FORS2 spectra with literature 800-1644 nm HST/WFC3 spectra, yielding a global spectrum from 400 to 1644 nm. We used the PLATON and Exoretrievals retrieval codes to interpret this spectrum, and find that both yield relatively deeper pressures where the atmosphere is optically thick at log-pressures between ${1.3}_{-1.1}^{+1.0}$ and ${0.29}_{-2.02}^{+1.86}$ bars, respectively. Exoretrievals finds solar to supersolar Na I and H2O log-mixing ratios of $-{5.4}_{-1.9}^{+2.0}$ and $-{4.5}_{-2.0}^{+2.0}$ , respectively, while PLATON finds an overall metallicity of ${\mathrm{log}}_{10}(Z/{Z}_{\odot })=-{0.49}_{-0.37}^{+1.0}$ dex. Therefore, our findings are in agreement with the literature and support the inference that the terminator of WASP-96b has few aerosols obscuring prominent features in the optical to near-infrared (near-IR) spectrum.

Keywords: Observational astronomy, Hot Jupiters, Transmission spectroscopy, Exoplanet astronomy, Exoplanet atmospheres
HD-TESS: An Asteroseismic Catalog of Bright Red Giants within TESS Continuous Viewing Zones. We present HD-TESS, a catalog of 1709 bright (V ~ 3-10) red giants from the Henry Draper (HD) Catalog with asteroseismic measurements based on photometry from NASA's Transiting Exoplanet Survey Satellite (TESS). Using light curves spanning at least 6 months across a single TESS observing cycle, we provide measurements of global asteroseismic parameters ( ${\nu }_{\max }$ and Δν) and the evolutionary state for each star in the catalog. We adopt literature values of atmospheric stellar parameters to estimate the masses and radii of the giants in our catalog using asteroseismic scaling relations, and observe that HD-TESS giants on average have larger masses compared to Kepler red giants. Additionally, we present the discovery of oscillations in 99 red giants in astrometric binary systems, including those with subdwarf or white dwarf companions. Finally, we benchmark radii from asteroseismic scaling relations against those measured using long-baseline interferometry for 18 red giants and find that correction factors to the scaling relations improve the agreement between asteroseismic and interferometric radii to approximately 3%.

Keywords: Stellar oscillations, Asteroseismology