Gaia's brightest very metal-poor (VMP) stars. Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2024

Gaia's brightest very metal-poor (VMP) stars. Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra

Akshara Viswanathan
  • Fonction : Auteur
Else Starkenburg
  • Fonction : Auteur
Tadafumi Matsuno
  • Fonction : Auteur
Kim A. Venn
  • Fonction : Auteur
Nicolas Longeard
  • Fonction : Auteur
Anke Ardern-Arentsen
  • Fonction : Auteur
Raymond G. Carlberg
  • Fonction : Auteur
Sébastien Fabbro
  • Fonction : Auteur
Martin Montelius
  • Fonction : Auteur
Federico Sestito
  • Fonction : Auteur

Résumé

Context. Gaia DR3 has offered the scientific community a remarkable dataset of approximately one million spectra acquired with the radial velocity spectrometer (RVS) in the calcium II triplet region, which is well suited to identify very metal-poor (VMP) stars. However, over 40% of these spectra have no released parameters by Gaia's GSP-Spec pipeline in the domain of VMP stars, whereas VMP stars are key tracers of early Galactic evolution.
Aims: We aim to provide spectroscopic metallicities for VMP stars using Gaia RVS spectra, thereby producing a catalogue of bright VMP stars distributed over the full sky that can serve as the basis for studies of early chemical evolution throughout the Galaxy.
Methods: We selected VMP stars using photometric metallicities from the literature and analysed the Gaia RVS spectra to infer spectroscopic metallicities for these stars.
Results: The inferred metallicities agree very well with literature high-resolution metallicities, with a median systematic offset of 0.1 dex and standard deviation of ∼0.15 dex. The purity of this sample in the VMP regime is ∼80%, with outliers representing a mere ∼3%.
Conclusions: We have built an all-sky catalogue of ∼1500 stars available, featuring reliable spectroscopic metallicities down to [Fe/H] ∼ −4.0, of which ∼1000 are VMP stars. More than 75% of these stars have either no spectroscopic metallicity value in the literature to date or have been flagged as unreliable in their literature spectroscopic metallicity estimates. This catalogue of bright (G < 13) VMP stars is three times larger than the current sample of well-studied VMP stars in the literature in this magnitude range, making it ideal for high-resolution spectroscopic follow-ups and studies of the properties of VMP stars in different parts of our Galaxy.

Full Table 1 is available at the CDS via anonymous ftp to https://cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/683/L11

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insu-04523178 , version 1 (27-03-2024)

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Akshara Viswanathan, Else Starkenburg, Tadafumi Matsuno, Kim A. Venn, Nicolas F. Martin, et al.. Gaia's brightest very metal-poor (VMP) stars. Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra. Astronomy and Astrophysics - A&A, 2024, 683, ⟨10.1051/0004-6361/202347944⟩. ⟨insu-04523178⟩
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