Sazuna/UAT_keywords huggingface dataset:
A Bayesian Analysis of Physical Parameters for 783 Kepler Close Binaries: Extreme-mass-ratio Systems and a New Mass Ratio versus Period Lower Limit. Contact binary star systems represent the long-lived penultimate phase of binary evolution. Population statistics of their physical parameters inform an understanding of binary evolutionary pathways and end products. We use light curves and new optical spectroscopy to conduct a pilot study of ten (near) contact systems in the long-period (P &gt; 0.5 days) tail of close binaries in the Kepler field. We use PHOEBE light-curve models to compute Bayesian probabilities on five principal system parameters. Mass ratios and third-light contributions measured from spectra agree well with those inferred from the light curves. Pilot study systems have extreme mass ratios q &lt; 0.32. Most are triples. Analysis of the unbiased sample of 783 0.15 d &lt; P &lt; 2 days (near) contact binaries results in 178 probable contact systems, 114 probable detached systems, and 491 ambiguous systems for which we report best-fitting and 16th-/50th-/84th-percentile parameters. Contact systems are rare at periods P &gt; 0.5 days, as are systems with q &gt; 0.8. There exists an empirical mass ratio lower limit ${q}_{\min }(P)$ ≈ 0.05-0.15 below which contact systems are absent, supporting a new set of theoretical predictions obtained by modeling the evolution of contact systems under the constraints of mass and angular momentum conservation. Premerger systems should lie at long periods and near this mass ratio lower limit, which rises from q = 0.044 for P = 0.74 days to q = 0.15 at P = 2.0 days. These findings support a scenario whereby nuclear evolution of the primary (more massive) star drives mass transfer to the primary, thus moving systems toward extreme q and larger P until the onset of the Darwin instability at ${q}_{\min }$ precipitates a merger.

Keywords: Multiple star evolution, Close binary stars, Markov chain Monte Carlo, Contact binary stars, Stellar evolution
Interstellar Complex Organic Molecules in SiO-traced Massive Outflows. The interstellar medium contains dust and gas, in which molecules can proliferate at high densities and in cold conditions. Interstellar complex organic molecules (iCOMs) are C-bearing species that contain at least six atoms. As they are detected in young stellar objects, iCOMs are expected to inhabit early stages of star formation evolution. In this study, we try to determine which iCOMs are present in the outflow component of massive protostars. To do this, we analyzed the morphological extension of blue- and redshifted iCOM emission in a sample of 11 massive protostars employing mapping observations at 1 mm within a ~1 GHz bandwidth for both the IRAM-30 m and APEX telescopes. We modeled the iCOM emission of the central pointing spectra of our objects using the XCLASS local thermal equilibrium radiative transfer code. We detected the presence of several iCOMs such as CH3OH, 13CH3OH, CH3OCHO, C2H5C15N, and (c-C3H2)CH2. In G034.41+0.24, G327.29-0.58, G328.81+0.63, G333.13-0.43, G340.97-1.02, G351.45+0.66, and G351.77-0.54, the iCOM lines show a faint broad-line profile. Due to the offset peak positions of the blue- and redshifted emission, covering from ~0.1 to 0.5 pc, these wings are possibly related to movements external to the compact core, such as large-scale low-velocity outflows. We have also established a correlation between the parent iCOM molecule CH3OH and the shock tracer SiO, reinforcing the hypothesis that shock environments provide the conditions to boost the formation of iCOMs via gas-phase reactions.

Keywords: Massive stars, Star forming regions, Interstellar molecules
Monitoring AGNs with Hβ Asymmetry. III. Long-term Reverberation Mapping Results of 15 Palomar-Green Quasars. In this third paper of the series reporting on the reverberation mapping campaign of active galactic nuclei with asymmetric Hβ emission-line profiles, we present results for 15 Palomar-Green quasars using spectra obtained between the end of 2016-2021 May. This campaign combines long time spans with relatively high cadence. For eight objects, both the time lags obtained from the entire light curves and the measurements from individual observing seasons are provided. Reverberation mapping of nine of our targets has been attempted for the first time, while the results for six others can be compared with previous campaigns. We measure the Hβ time lags over periods of years and estimate their black hole masses. The long duration of the campaign enables us to investigate their broad-line region (BLR) geometry and kinematics for different years by using velocity-resolved lags, which demonstrate signatures of diverse BLR geometry and kinematics. The BLR geometry and kinematics of individual objects are discussed. In this sample, the BLR kinematics of Keplerian/virialized motion and inflow is more common than that of outflow.

Keywords: Supermassive black holes, Quasars, Reverberation mapping, Active galaxies, Active galactic nuclei
Spectral Energy Distributions in Three Deep-drilling Fields of the Vera C. Rubin Observatory Legacy Survey of Space and Time: Source Classification and Galaxy Properties. W-CDF-S, ELAIS-S1, and XMM-LSS will be three Deep-Drilling Fields (DDFs) of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), but their extensive multiwavelength data have not been fully utilized as done in the COSMOS field, another LSST DDF. To prepare for future science, we fit source spectral energy distributions (SEDs) from X-ray to far-infrared in these three fields mainly to derive galaxy stellar masses and star formation rates. We use CIGALE v2022.0, a code that has been regularly developed and evaluated, for the SED fitting. Our catalog includes 0.8 million sources covering 4.9 deg2 in W-CDF-S, 0.8 million sources covering 3.4 deg2 in ELAIS-S1, and 1.2 million sources covering 4.9 deg2 in XMM-LSS. Besides fitting normal galaxies, we also select candidates that may host active galactic nuclei (AGNs) or are experiencing recent star formation variations and use models specifically designed for these sources to fit their SEDs; this increases the utility of our catalog for various projects in the future. We calibrate our measurements by comparison with those in well-studied smaller regions and briefly discuss the implications of our results. We also perform detailed tests of the completeness and purity of SED-selected AGNs. Our data can be retrieved from a public website.

Keywords: Celestial objects catalogs, Active galactic nuclei, Sky surveys, Galaxies
Gas Column Density Distribution of Molecular Clouds in the Third Quadrant of the Milky Way. We have obtained column density maps for an unbiased sample of 120 molecular clouds in the third quadrant of the Milky Way midplane (b ≤ ∣5∣°) within the Galactic longitude range from 195° to 225°, using the high-sensitivity 12CO and 13CO (J = 1 - 0) data from the Milky Way Imaging Scroll Painting (MWISP) project. The probability density functions of the molecular hydrogen column density of the clouds, N-pdfs, are fitted with both a lognormal (LN) function and a lognormal plus power-law (LN+PL) function. The molecular clouds are classified into three categories according to their shapes of N-pdfs, i.e., LN, LN+PL, and UN (unclear). About 72% of the molecular clouds fall into the LN category, while 18% and 10% fall into the LN+PL and UN categories, respectively. A PL scaling relation, ${\sigma }_{s}\propto {N}_{{{\rm{H}}}_{2}}^{0.44}$ , exists between the width of the N-pdf, σ  s , and the average column density, ${N}_{{{\rm{H}}}_{2}}$ , of the molecular clouds. However, σ  s  shows no correlation with the mass of the clouds. A correlation is found between the dispersion of normalized column density, σ  N/&lt;N&gt;, and the sonic Mach number, ${ \mathcal M }$ , of molecular clouds. Overall, as predicted by numerical simulations, the N-pdfs of the molecular clouds with active star formation activity tend to have N-pdfs with PL high-density tails.

Keywords: Surveys, Molecular clouds, Star formation, Interstellar clouds, Interstellar medium
Binding Energy Evaluation Platform: A Database of Quantum Chemical Binding Energy Distributions for the Astrochemical Community. The quality of astrochemical models is highly dependent on reliable binding energy (BE) values that consider the morphological and energetic variety of binding sites on the surface of ice-grain mantles. Here, we present the Binding Energy Evaluation Platform (BEEP) and database that, using quantum chemical methods, produces full BE distributions of molecules bound to an amorphous solid water (ASW) surface model. BEEP is highly automatized and allows one to sample binding sites on a set of water clusters and to compute accurate BEs. Using our protocol, we computed 21 BE distributions of interstellar molecules and radicals on an amorphized set of 15-18 water clusters of 22 molecules each. The distributions contain between 225 and 250 unique binding sites. We apply a Gaussian fit and report the mean and standard deviation for each distribution. We compare with existing experimental results and find that the low- and high-coverage experimental BEs coincide well with the high-BE tail and mean value of our distributions, respectively. Previously reported single BE theoretical values are broadly in line with ours, even though in some cases significant differences can be appreciated. We show how the use of different BE values impacts a typical problem in astrophysics, such as the computation of snow lines in protoplanetary disks. BEEP will be publicly released so that the database can be expanded to other molecules or ice models in a community effort.

Keywords: Ice formation, Astrochemistry, Surface ices, Protoplanetary disks, Interstellar dust processes
The Spectral Energy Distributions for 4FGL Blazars. In this paper, the multiwavelength data from radio to X-ray bands for 2709 blazars in the 4FGL-DR3 catalog are compiled to calculate their spectral energy distributions using a parabolic equation $\mathrm{log}(\nu {f}_{\nu })={P}_{1}{\left(\mathrm{log}\nu -{P}_{2}\right)}^{2}+{P}_{3}$ . Some important parameters including spectral curvature (P 1), synchrotron peak frequency (P 2, $\mathrm{log}{\nu }_{{\rm{p}}}$ ), and peak luminosity ( $\mathrm{log}{L}_{{\rm{p}}}$ ) are obtained. Based on those parameters, we discussed the classification of blazars using the "Bayesian classification" and investigated some mutual correlations. We came to the following results. (1) Based on the Bayesian classification of synchrotron peak frequencies, the 2709 blazars can be classified into three subclasses, i.e., $\mathrm{log}({\nu }_{{\rm{p}}}/\mathrm{Hz})\lt 13.7$ for low synchrotron peak blazars (LSPs), $13.7\lt \mathrm{log}({\nu }_{{\rm{p}}}/\mathrm{Hz})\lt 14.9$ for intermediate synchrotron peak blazars (ISPs), and $\mathrm{log}({\nu }_{{\rm{p}}}/\mathrm{Hz})\gt 14.9$ for high synchrotron peak blazars (HSPs), and there are 820 HSPs, 750 ISPs, and 1139 LSPs. (2) The γ-ray emission has the closest relationship with radio emission, followed by optical emission, while the weakest relationship is that with X-ray emission. The γ-ray luminosity is also correlated with the synchrotron peak luminosity. (3) There are strong positive correlations between the curvature (1/∣P 1∣) and the peak frequency ( $\mathrm{log}{\nu }_{{\rm{p}}}$ ) for all subclasses (FSRQs, (high, intermediate, and low) BL Lacertae objects). For different subclasses, the correlation slopes are different, which implies that there are different acceleration mechanisms and emission processes for different subclasses of blazars.

Keywords: BL Lacertae objects, Quasars, Gamma-ray sources, Blazars, Active galactic nuclei, Spectral energy distribution
An Atlas of Convection in Main-sequence Stars. Convection is ubiquitous in stars and occurs under many different conditions. Here we explore convection in main-sequence stars through two lenses: dimensionless parameters arising from stellar structure and parameters that emerge from the application of mixing length theory. We first define each quantity in terms familiar to both the 1D stellar evolution community and the hydrodynamics community. We then explore the variation of these quantities across different convection zones, different masses, and different stages of main-sequence evolution. We find immense diversity across stellar convection zones. Convection occurs in thin shells, deep envelopes, and nearly spherical cores; it can be efficient or inefficient, rotationally constrained or not, transsonic or deeply subsonic. This atlas serves as a guide for future theoretical and observational investigations by indicating which regimes of convection are active in a given star, and by describing appropriate model assumptions for numerical simulations.

Keywords: Stellar physics, Stellar evolutionary models, Stellar convective zones
Mass and Age Determination of the LAMOST Data with Different Machine-learning Methods. We present a catalog of 948,216 stars with mass labels and a catalog of 163,105 red clump (RC) stars with mass and age labels simultaneously. The training data set is crossmatched from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR5, and high-resolution asteroseismology data, mass, and age are predicted by the random forest (RF) method or a convex-hull algorithm. The stellar parameters with a high correlation with mass and age are extracted and the test data set shows that the median relative error of the prediction model for the mass of the large sample is 3%, and for the mass and age of RC stars is 4% and 7%. We also compare the predicted age of RC stars with recent works and find that the final uncertainty of the RC sample could reach 18% for age and 9% for mass; meanwhile, the final precision of the mass for the large sample with different types of stars could reach 13% without considering systematics. All of this implies that this method could be widely used in the future. Moreover, we explore the performance of different machine-learning methods for our sample, including Bayesian linear regression and the gradient-boosting decision tree (GBDT), multilayer perceptron, multiple linear regression, RF, and support vector regression methods. Finally, we find that the performance of a nonlinear model is generally better than that of a linear model, and the GBDT and RF methods are relatively better.

Keywords: Random Forests, Support vector machine, Stellar ages, Stellar masses
3D Selection of 167 Substellar Companions to Nearby Stars. We analyze 5108 AFGKM stars with at least five high-precision radial velocity points, as well as Gaia and Hipparcos astrometric data, utilizing a novel pipeline developed in previous work. We find 914 radial velocity signals with periods longer than 1000 days. Around these signals, 167 cold giants and 68 other types of companions are identified, through combined analyses of radial velocity, astrometry, and imaging data. Without correcting for detection bias, we estimate the minimum occurrence rate of the wide-orbit brown dwarfs to be 1.3%, and find a significant brown-dwarf valley around 40 M Jup. We also find a power-law distribution in the host binary fraction beyond 3 au, similar to that found for single stars, indicating no preference of multiplicity for brown dwarfs. Our work also reveals nine substellar systems (GJ 234 B, GJ 494 B, HD 13724 b, HD 182488 b, HD 39060 b and c, HD 4113 C, HD 42581 d, HD 7449 B, and HD 984 b) that have previously been directly imaged, and many others that are observable at existing facilities. Depending on their ages, we estimate that an additional 10-57 substellar objects within our sample can be detected with current imaging facilities, extending the imaged cold (or old) giants by an order of magnitude.

Keywords: Exoplanet detection methods, Brown dwarfs, Astrometric exoplanet detection, Exoplanet catalogs, Exoplanet astronomy, Radial velocity
Simulating the Legacy Survey of Space and Time Stellar Content with TRILEGAL. We describe a large simulation of the stars to be observed by the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). The simulation is based on the TRILEGAL code, which resorts to large databases of stellar evolutionary tracks, synthetic spectra, and pulsation models, added to simple prescriptions for the stellar density and star formation histories of the main structures of the Galaxy, to generate mock stellar samples through a population synthesis approach. The main bodies of the Magellanic Clouds are also included. A complete simulation is provided for single stars, down to the r = 27.5 mag depth of the coadded Wide-Fast-Deep survey images. A second simulation is provided for a fraction of the binaries, including the interacting ones, as derived with the BinaPSE module of TRILEGAL. We illustrate the main properties and numbers derived from these simulations, including: comparisons with real star counts; the expected numbers of Cepheids, long-period variables, and eclipsing binaries; the crowding limits as a function of seeing and filter; the star-to-galaxy ratios. Complete catalogs are accessible through the NOIRLab Astro Data Lab, while the stellar density maps are incorporated in the LSST metrics analysis framework.

Keywords: Local Group, Small Magellanic Cloud, Galactic bulge, Large Magellanic Cloud, Milky Way Galaxy
SWASTi-SW: Space Weather Adaptive Simulation Framework for Solar Wind and Its Relevance to the Aditya-L1 Mission. Solar wind streams, acting as a background, govern the propagation of space weather drivers in the heliosphere, which induce geomagnetic storm activities. Therefore, predictions of the solar wind parameters are the core of space weather forecasts. This work presents an indigenous three-dimensional (3D) solar wind model (SWASTi-SW). This numerical framework for forecasting the ambient solar wind is based on a well-established scheme that uses a semiempirical coronal model and a physics-based inner heliospheric model. This study demonstrates a more generalized version of the Wang-Sheeley-Arge relation, which provides a speed profile input to the heliospheric domain. Line-of-sight observations of GONG and Helioseismic and Magnetic Imager magnetograms are used as inputs for the coronal model, which in turn provides the solar wind plasma properties at 0.1 au. These results are then used as an initial boundary condition for the magnetohydrodynamics model of the inner heliosphere to compute the solar wind properties up to 2.1 au. Along with the validation run for multiple Carrington rotations, the effect of variation of specific heat ratio and study of the stream interaction region (SIR) are also presented. This work showcases the multidirectional features of SIRs and provides synthetic measurements for potential observations from the Solar Wind Ion Spectrometer subsystem of the Aditya Solar wind Particle Experiment payload on board ISRO's upcoming solar mission Aditya-L1.

Keywords: Solar wind, Interplanetary magnetic fields, Magnetohydrodynamical simulations
Likelihood-free Inference with the Mixture Density Network. In this work, we propose using the mixture density network (MDN) to estimate cosmological parameters. We test the MDN method by constraining parameters of the ΛCDM and wCDM models using Type Ia supernovae and the power spectra of the cosmic microwave background. We find that the MDN method can achieve the same level of accuracy as the Markov Chain Monte Carlo method, with a slight difference of ${ \mathcal O }({10}^{-2}\sigma )$ . Furthermore, the MDN method can provide accurate parameter estimates with ${ \mathcal O }({10}^{3})$ forward simulation samples, which are useful for complex and resource-consuming cosmological models. This method can process either one data set or multiple data sets to achieve joint constraints on parameters, extendable for any parameter estimation of complicated models in a wider scientific field. Thus, the MDN provides an alternative way for likelihood-free inference of parameters.

Keywords: Neural networks, Cosmological parameters, Observational cosmology, Astronomy data analysis, Computational methods
An Updated Metal-dependent Theoretical Scenario for Classical Cepheids. To properly quantify the possible residual systematic errors affecting the classical Cepheid distance scale, a detailed theoretical scenario is recommended. By extending the set of nonlinear, convective pulsation models published for Z = 0.02 to Z = 0.004, Z = 0.008, and Z = 0.03, we provide a detailed homogeneous, nonlinear model grid taking into account simultaneous variations of the mass-luminosity relation, the efficiency of superadiabatic convection, and the chemical composition. The dependence of the inferred period-radius, period-mass-radius, and period-mass-luminosity-temperature relations on the input parameters is discussed for both the fundamental and first overtone modes. The trend of the instability strip getting redder as the metallicity increases is confirmed for the additional mass-luminosity assumptions and mixing length values. From the obtained multifilter light curves, we derive the mean magnitudes and colors, and in turn the period-luminosity-color and period-Wesenheit relations, for each assumed chemical composition, mass-luminosity relation, and efficiency of superadiabatic convection. Application to a well-studied sample of Cepheids in the Large Magellanic Cloud allows us to constrain the dependence of the inferred distance modulus on the assumed mass-luminosity relation, and the inclusion of the metallicity term in the derivation of the period-Wesenheit relations allows us, for each assumed mass-luminosity relation, to predict the metallicity dependence of the Cepheid distance scale. The obtained metal-dependent, period-Wesenheit relations are compared with recent results in the literature and applied to a sample of Gaia Early Data Release 3 Galactic Cepheids with known metal abundances to derive individual parallaxes. The comparison of these predictions with Gaia results is finally discussed.

Keywords: Distance indicators, Cepheid variable stars, Cepheid distance, Pulsating variable stars
The Formation of the Stripped-envelope Type IIb Supernova Progenitors: Rotation, Metallicity, and Overshooting. Type IIb supernovae (SNe) are believed to originate from core-collapse progenitors having kept only a very thin hydrogen envelope. We aim to explore how some physical factors, such as rotation, metallicity, overshooting, and the initial orbital period in binaries significantly affect the Roche lobe overflow and the formation of Type IIb SNe (also denoted SNe IIb). It is found that binaries are the main channel that are capable of producing Type IIb SNe progenitors in the mass range for initial masses below 20 M ⊙. The formation of Type IIb SNe progenitors is extremely sensitive to the initial orbital period. A less massive hydrogen envelope mass indicates a smaller radius and higher effective temperatures, and vice versa. Binary systems with initial periods between 300 and 720 days produce Type IIb progenitors that are a red supergiant. Those with an initial period between 50 and 300 days produce yellow supergiant progenitors, and those with initial periods shorter than 50 days blue supergiant progenitors. Both rapid rotation and larger overshooting can enlarge the carbon-oxygen core mass and lead to higher core temperature and lower central density at the precollapse phase. They are also beneficial to surface nitrogen enrichment but restrict the efficiency of the first dredge-up. SN IIb progenitors with low metallicity have smaller hydrogen envelope masses and radii than their high-metallicity counterparts. Ultrastripped binary models have systematically higher core mass fraction 12C left, which has an important influence on the compactness of Type IIb progenitors.

Keywords: Stellar structures, Stellar properties, Close binary stars, Massive stars, Stellar rotation