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Large-amplitude variables in Gaia Data Release 2. Multi-band variability characterization
- Source :
- A&A 648, A44 (2021)
- Publication Year :
- 2020
-
Abstract
- The second data release (DR2) of Gaia provides mean photometry in three bands for $\sim$1.4 billion sources, but light curves and variability properties are available for only $\sim$0.5 million of them. Here, we provide a census of large-amplitude variables with amplitudes larger than $\sim$0.2 mag in the $G$ band for objects with mean brightnesses between 5.5 and 19 mag. To achieve this, we rely on variability amplitude proxies in $G$, $G_{BP}$ and $G_{RP}$ computed from the uncertainties on the magnitudes published in DR2. We then apply successive filters to identify two subsets containing respectively sources with reliable mean $G_{BP}$ and $G_{RP}$ (for studies using colours) and sources having compatible amplitude proxies in $G$, $G_{BP}$ and $G_{RP}$ (for multi-band variability studies). The full catalogue gathers $23\,315\,874$ large-amplitude variable candidates, and the two subsets with increased levels of purity contain respectively $1\,148\,861$ and $618\,966$ sources. A multi-band variability analysis of the catalogue shows that different types of variable stars can be globally categorized in four groups according to their colour and blue-to-red amplitude ratios as determined from the $G$, $G_{BP}$ and $G_{RP}$ amplitude proxies. The catalogue constitutes the first census of Gaia large-amplitude variable candidates, extracted from the public DR2 archive. The overview presented here illustrates the added-value of the mission for multi-band variability studies even at this stage when epoch photometry is not yet available for all sources. (Abridged abstract)<br />Comment: Final version, A&A, in press. Main text: 20 pages, 26 figures. Four appendixes
- Subjects :
- Astrophysics - Solar and Stellar Astrophysics
Subjects
Details
- Database :
- arXiv
- Journal :
- A&A 648, A44 (2021)
- Publication Type :
- Report
- Accession number :
- edsarx.2009.07746
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1051/0004-6361/202039450