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A method is developed for fitting theoretically predicted astronomical spectra to an observed spectrum. Using a hierarchical Bayesian principle, the method takes both systematic and statistical measurement errors into account, which has not…

Astrophysics · Physics 2008-11-26 Z. Shkedy , L. Decin , G. Molenberghs , C. Aerts

We present a new machine learning model for estimating photometric redshifts with improved accuracy for galaxies in Pan-STARRS1 data release 1. Depending on the estimation range of redshifts, this model based on neural networks can handle…

Instrumentation and Methods for Astrophysics · Physics 2021-12-09 Joongoo Lee , Min-Su Shin

$Context$. Gaia Second Data Release provides precise astrometry and photometry for more than 1.3 billion sources. This catalog opens a new era concerning the characterization of open clusters and test stellar models, paving the way for a…

The latest Gaia data release in July 2022, DR3, added a number of important data products to those available in earlier releases, including radial velocity data, information on stellar multiplicity and XP spectra of a selected sample of…

Solar and Stellar Astrophysics · Physics 2023-09-01 O. Vincent , M. A. Barstow , S. Jordan , C. Mander , P. Bergeron , P. Dufour

Regression methods based in Machine Learning Algorithms (MLA) have become an important tool for data analysis in many different disciplines. In this work, we use MLA in an astrophysical context; our goal is to measure the mean longitudinal…

Solar and Stellar Astrophysics · Physics 2018-11-07 J. C. Ramirez-Velez , C. Yañez-Marquez , J. P. Cordova-Barbosa

The second data release of the Gaia mission includes an advance catalog of variable stars. The classification of these stars are based on sparse photometry from the first 22 months of the mission. We set out to investigate the purity and…

Solar and Stellar Astrophysics · Physics 2018-12-12 László Molnár , Emese Plachy , Áron L. Juhász , Lorenzo Rimoldini

(Abridged) Gaia aims to make a 3-dimensional map of 1,000 million stars in our Milky Way to unravel its kinematical, dynamical, and chemical structure and evolution. Gaia's on-board detection software discriminates stars from spurious…

Instrumentation and Methods for Astrophysics · Physics 2015-04-01 J. H. J. de Bruijne , M. Allen , S. Azaz , A. Krone-Martins , T. Prod'homme , D. Hestroffer

We set out to determine stellar labels from low-resolution survey spectra of hot, OBA stars with effective temperature (Teff) higher than 7500K. This fills a gap in the scientific analysis of large spectroscopic stellar surveys such as…

The measurement of atmospheric parameters is fundamental for scientific research using stellar spectra. The Chinese Space Station Telescope (CSST), scheduled to be launched in 2024, will provide researchers with hundreds of millions of…

Solar and Stellar Astrophysics · Physics 2024-08-21 JiaRui Rao , HaiLiang Chen , JianPing Xiong , LuQian Wang , YanJun Guo , JiaJia Li , Chao Liu , ZhanWen Han , XueFei Chen

Estimating stellar masses for billions of galaxies in upcoming surveys requires methods that are both accurate and computationally efficient. We present a new approach using symbolic regression trained on a simulation to derive simple,…

We investigate whether Gaia can specify the binary fractions of massive stellar populations in the Galactic disk through astrometric microlensing. Furthermore, we study if some information about their mass distributions can be inferred via…

Solar and Stellar Astrophysics · Physics 2015-04-14 Sedighe Sajadian

In light of substantial new discoveries of hot subdwarfs by ongoing spectroscopic surveys and the availability of new all-sky data from ground-based photometric surveys and the Gaia mission Data Release 2, we compiled an updated catalogue…

Solar and Stellar Astrophysics · Physics 2020-04-08 S. Geier

Gaia measures the five astrometric parameters for stars in the Milky Way, but only four of them (positions and proper motion, but not parallax) are well measured beyond a few kpc from the Sun. Modern spectroscopic surveys such as APOGEE…

Astrophysics of Galaxies · Physics 2019-08-21 Henry W. Leung , Jo Bovy

Large Galactic stellar surveys and new generations of stellar atmosphere models and spectral line formation computations need to be subjected to careful calibration and validation and to benchmark tests. We focus on cool stars and aim at…

Solar and Stellar Astrophysics · Physics 2015-10-07 U. Heiter , P. Jofré , B. Gustafsson , A. J. Korn , C. Soubiran , F. Thévenin

The effective temperature, one of the most fundamental atmospheric parameters of a star, can be estimated using various methods, and here we focus on the method using line-depth ratios (LDRs). This method combines low- and high-excitation…

Future space and ground-based survey programmes will produce an impressive amount of photometric data. The GAIA space mission will map the complete sky down to mag V=20 and produce time series for about 1 billion stars. Survey instruments…

Astrophysics · Physics 2007-05-23 Laurent Eyer , Jan Cuypers

We present a catalogue of distances, masses and ages for $\sim3$ million stars in the second Gaia data release with spectroscopic parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE and SEGUE. We…

Astrophysics of Galaxies · Physics 2018-09-24 Jason L. Sanders , Payel Das

Different stellar populations may be identified through differences in chemical, kinematic, and chronological properties, suggesting the interplay of various physical mechanisms that led to their origin and subsequent evolution. As such,…

Astrophysics of Galaxies · Physics 2025-03-26 A. W. Neitzel , T. L. Campante , D. Bossini , A. Miglio

With the dual aims of enlarging the list of extremely metal-poor stars identified in the Galaxy, and boosting the numbers of moderately metal-deficient stars in directions that sample the rotational properties of the thick disk, we have…

Context: Quantitative spectroscopy of luminous blue stars relies on detailed non-LTE model atmospheres whose increasing physical realism makes direct, iterative analyses computationally demanding. Aims: We introduce MAUI (Machine-learning…

Solar and Stellar Astrophysics · Physics 2026-01-06 Miguel A. Urbaneja