• DOI:10.1051/0004-6361/201629512
• Corpus ID: 1828208

Gaia Data Release 1 Summary of the astrometric, photometric, and survey properties

@article{Brown2016GaiaDR,
  title={Gaia Data Release 1 Summary of the astrometric, photometric, and survey properties},
  author={G. C. Brown and Antonella Vallenari and Timo Prusti and Jos H.J. de Bruijne and François Mignard and Ronald Drimmel and 585 co-authors Leiden Observatory and Leiden University and INAF-Osservatorio astronomico di Padova and ESA-Estec and Observatoire de la C{\^o}te d'Azur and INAF-Osservatorio Astrofisico di Torino},
  journal={Astronomy and Astrophysics},
  year={2016},
  volume={595},
  pages={1-23}
}

• G. C. Brown, A. Vallenari, +9 authors I. Torino
• Published 14 September 2016
• Physics, Geology
• Astronomy and Astrophysics

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7.
Aims: A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release.
Methods: The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue.
Results: Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the Hipparcos and Tycho-2 catalogues - a realisation of the Tycho-Gaia Astrometric Solution (TGAS) - and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of 3000 Cepheid and RR Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr-1 for the proper motions. A systematic component of 0.3 mas should be added to the parallax uncertainties. For the subset of 94 000 Hipparcos stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr-1. For the secondary astrometric data set, the typical uncertainty of the positions is 10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to
0.03 mag over the magnitude range 5 to 20.7.
Conclusions: Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data.