Clean catalogues of blue horizontal-branch stars using Gaia EDR3
- Context. Blue horizontal-branch stars evolve from low-mass stars that have completed their main-sequence lifetimes and undergone a helium flash at the end of their red-giant phase. As such, blue horizontal-branch stars are very old objects that can be used as markers in studies of the Galactic structure and formation history. To create a clean sky catalogue of blue horizontal-branch stars, we cross-matched the Gaia data release 2 (DR2) dataset with existing reference catalogues to define selection criteria based on Gaia DR2 parameters. Following the publication of Gaia early data release 3 (EDR3), these methods were verified and subsequently applied to this latest release. Aims. Previous catalogues of blue horizontal-branch stars were developed using spectral analyses or were restricted to individual globular clusters. The purpose of this catalogue is to identify a set of blue horizontal-branch star candidates that have been selected using photometric and astrometric observations and exhibits a low contamination rate. This hasContext. Blue horizontal-branch stars evolve from low-mass stars that have completed their main-sequence lifetimes and undergone a helium flash at the end of their red-giant phase. As such, blue horizontal-branch stars are very old objects that can be used as markers in studies of the Galactic structure and formation history. To create a clean sky catalogue of blue horizontal-branch stars, we cross-matched the Gaia data release 2 (DR2) dataset with existing reference catalogues to define selection criteria based on Gaia DR2 parameters. Following the publication of Gaia early data release 3 (EDR3), these methods were verified and subsequently applied to this latest release. Aims. Previous catalogues of blue horizontal-branch stars were developed using spectral analyses or were restricted to individual globular clusters. The purpose of this catalogue is to identify a set of blue horizontal-branch star candidates that have been selected using photometric and astrometric observations and exhibits a low contamination rate. This has been deemed important as the success of the Gaia mission has changed the way that targets are selected for large-scale spectroscopic surveys, meaning that far fewer spectra will be acquired for blue horizontal-branch stars in the future unless they are specifically targeted. <br /> Methods. We cross-matched reference blue horizontal-branch datasets with the Gaia DR2 database and defined two sets of selection criteria. Firstly, in Gaia DR2 - colour and absolute G magnitude space, and secondly, in Gaia DR2 - colour and reduced proper motion space. The main-sequence contamination in both subsets of the catalogue was reduced, at the expense of completeness, by concentrating on the Milky Way's Galactic halo, where relatively young main-sequence stars were not expected. The entire catalogue is limited to those stars with no apparent neighbours within 5 arcsec. These methods were verified and subsequently applied to the Gaia EDR3. Results. We present a catalogue, based on Gaia EDR3, of 57 377 blue horizontal-branch stars. The Gaia EDR3 parallax was used in selecting 16 794 candidates and the proper motions were used to identify a further 40 583 candidates.…
Verfasserangaben: | Rick Culpan, Ingrid PelisoliORCiD, Stephan GeierORCiDGND |
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DOI: | https://doi.org/10.1051/0004-6361/202040074 |
ISSN: | 1432-0746 |
Titel des übergeordneten Werks (Englisch): | Astronomy and astrophysics : an international weekly journal / European Southern Observatory (ESO) |
Verlag: | EDP Sciences |
Verlagsort: | Les Ulis |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Datum der Erstveröffentlichung: | 19.10.2021 |
Erscheinungsjahr: | 2021 |
Datum der Freischaltung: | 19.09.2023 |
Freies Schlagwort / Tag: | Galaxy: stellar content; Hertzsprung-Russell and C-M diagrams; catalogs; stars: horizontal-branch |
Band: | 654 |
Aufsatznummer: | A107 |
Seitenanzahl: | 14 |
Fördernde Institution: | Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG) [GE2506/12-1]; UK's Science and Technology Facilities Council (STFC)UK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC) [ST/T000406/1] |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
Peer Review: | Referiert |