Bibcode
Ye, Xianhao; Wu, Wenbo; Allende Prieto, Carlos; Aguado, David S.; Zhao, Jingkun; González Hernández, Jonay I.; Rebolo, Rafael; Zhao, Gang; Li, Zhuohan; del Burgo, Carlos; Chen, Yuqin
Bibliographical reference
Astronomy and Astrophysics
Advertised on:
3
2025
Journal
Citations
8
Refereed citations
6
Description
Context. Gaia Bp/Rp spectrophotometry for over two hundred million stars has been publicly released as part of Gaia Data Release 3 (DR3). These data have great potential for mapping metallicity across the Milky Way. Several recent studies have analyzed this data set to derive atmospheric parameters and identify new metal-poor stars. In addition, systematics in the fluxes of the Bp/Rp spectra have also been identified and characterized. Aims. We aim to construct an alternative catalog of atmospheric parameters from Gaia Bp/Rp spectra by fitting them with synthetic spectra based on model atmospheres, and provide corrections to the Bp/Rp fluxes according to stellar colors, magnitudes, and interstellar extinction. Methods. We use GaiaXPy to obtain calibrated spectra and apply FERЯ to match the corrected Bp/Rp spectra with models and infer atmospheric parameters. We train a neural network (NN) using stars in the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to predict flux corrections as a function of wavelength for each target. Results. Based on the comparison with APOGEE parameters, we conclude that our estimated parameters have systematic errors and uncertainties in Teff, log g, and [M/H] about ‑38 ± 167 K, 0.05 ± 0.40 dex, and ‑0.12 ± 0.19 dex, respectively, for stars in the range 4000 ≤ Teff ≤ 7000 K. The corrected Bp/Rp spectra show improved agreement with both models and Hubble Space Telescope (HST) CALSPEC data. Our correction increases the precision of the relative spectrophotometry of the Bp/Rp data from 3.2–3.7% to 1.2–2.4%. We also compare our results with other similar catalogs from the literature and validate them using star clusters. Finally, we have built a catalog of atmospheric parameters for stars within 4000 ≤ Teff ≤ 7000 K, comprising 68 394 431 sources, along with a subset of 124 188 stars with [M/H] ≤ ‑2.5. Our catalogs and flux correction code are publicly available. Conclusions. Our results confirm that the Gaia Bp/Rp flux calibrated spectra show systematic patterns as a function of wavelength that are tightly related to colors, magnitudes, and extinction. Our optimization algorithm can give us accurate atmospheric parameters of stars with a clear and direct link to models of stellar atmospheres, and can be used to efficiently search for extremely metal-poor (EMP) stars.
Related projects
Chemical Abundances in Stars
Stellar spectroscopy allows us to determine the properties and chemical compositions of stars. From this information for stars of different ages in the Milky Way, it is possible to reconstruct the chemical evolution of the Galaxy, as well as the origin of the elements heavier than boron, created mainly in stellar interiors. It is also possible to
Carlos
Allende Prieto