Gaia Data Release 1 (Gaia DR1)

Contents of Gaia DR1 Positions (α, δ) and G magnitudes for all 1,142,679,769 sources with acceptable formal standard errors on positions. Positions and individual uncertainties are computed using a generic prior and Bayes' rule. The five-parameter astrometric solution - positions, parallaxes, and proper motions - for 2,057,050 stars in common between the Tycho-2 Catalogue and Gaia. This part of Gaia DR1 is based on the Tycho-Gaia Astrometric Solution (TGAS). Photometric data of selected RR Lyrae and Cepheid variable stars included in the high-cadence measurements executed at the beginning of the routine phase, for a period of 4 weeks, in a special scanning mode repeatedly covering the ecliptic poles on every spin for calibration purposes. Positions (α, δ) and G magnitudes for 2152 ICRF quasars. Cross-matches between Gaia sources on the one hand and Hipparcos-2, Tycho-2, 2MASS PSC, GSC2.3, PPM-XL, UCAC-4, SDSS DR10 / DR12, AllWISE, and URAT-1 data on the other hand. For more information, see https://www.cosmos.esa.int/web/gaia/data-release-1 Gaia Data Release 1 papers: https://www.cosmos.esa.int/web/gaia/dr1-papers Gaia Data Release 1 documentation: https://gea.esac.esa.int/archive/documentation/GDR1/index.html