Gaia Data Release 2

By L. Lindegren, José A. Gómez Hernández, A. Bombrun, S. Klioner, U. Bastian, M. Ramos-Lerate, A. Torres, H. Steidelmüller, C. Stephenson, D. Hobbs and 81 more. Astronomy & Astrophysics, 2018

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Context. Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the European Space Agency Gaia satellite during the first 22 months of its operational phase. Aims. We describe the input data, models, and processing used for the astrometric content of Gaia DR2, and the validation of these resultsperformed within the astrometry task. Methods. Some 320 billion centroid positions from the pre-processed astrometric CCD observations were used to estimate the five astrometric parameters (positions, parallaxes, and proper motions) for 1332 million sources, and approximate positions at the reference epoch J2015.5 for an additional 361 million mostly faint sources. These data were calculated in two steps. First, the satellite attitude and the astrometric calibration parameters of the CCDs were obtained in an astrometric global iterative solution for 16 million selected sources, using about 1% of the input data. This primary solution was tied to the extragalactic International Celestial Reference System (ICRS) by means of quasars. The resulting attitude and calibration were then used to calculate the astrometric parameters of all the sources. Special validation solutions were used to characterise the random and systematic errors in parallax and proper motion. Results. For the sources with five-parameter astrometric solutions, the median uncertainty in parallax and position at the reference epoch J2015.5 is about 0.04 mas for bright (G < 14 mag) sources, 0.1 mas at G = 17 mag, and 0.7 masat G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr−1, respectively.The optical reference frame defined by Gaia DR2 is aligned with ICRS and is non-rotating with respect to the quasars to within 0.15 mas yr−1. From the quasars and validation solutions we estimate that systematics in the parallaxes depending on position, magnitude, and colour are generally below 0.1 mas, but the parallaxes are on the whole too small by about 0.03 mas. Significant spatial correlations of up to 0.04 mas in parallax and 0.07 mas yr−1 in proper motion are seen on small (< 1 deg) and intermediate (20 deg) angular scales. Important statistics and information for the users of the Gaia DR2 astrometry are given in the appendices.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

AGaiaData Release 2 catalogue of white dwarfs and a comparison with SDSS (2018, background): “By contrast, Gaia Data Release 2 (DR2; Gaia Collaboration et al. 2018a) is more complete by orders of magnitude, and it provides precise astrometry (Lindegren et al. 2018) as well as GBP (330–680 nm), GRP (640–1000 nm), and G (330–1000 nm) passband photometry (Evans et al. 2018).”
The Gaia–Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age (2020, background): “More recently, Gaia parallaxes (Gaia Collaboration et al. 2018; Lindegren et al. 2018) have better constrained the stellar radii of the vast majority of Kepler host stars, followed by more detailed investigations of the valley as a function of stellar mass (Fulton & Petigura 2018), metallicity…”
Gaia-2MASS 3D maps of Galactic interstellar dust within 3 kpc (2019, methodology): “Distances are derived from Gaia DR2 parallaxes, after subtraction of the zero point -0.03 mas (Arenou et al. 2018; Lindegren et al. 2018).”
The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch (2019, methodology): “While awaiting improved parallax results from Gaia, we have updated the absolute magnitude calibration of the I-band TRGB for the LMC.”
Abundance Estimates for 16 Elements in 6 Million Stars from LAMOST DR5 Low-Resolution Spectra (2019, methodology): “We have adopted a global zero-point correction of 29µas to the Gaia parallax (Lindegren et al. 2018).”
A 3D Dust Map Based on Gaia, Pan-STARRS 1, and 2MASS (2019, background): “Gaia DR2 contains five-parameter astrometric determinations for 1.3 billion sources (Lindegren et al. 2018).”
Gaia Data Release 2 (2018, background): “Systematic errors at low levels nonetheless exist in Gaia DR2 (see Arenou et al. 2018; Lindegren et al. 2018).”
Characterizing the Fast Radio Burst Host Galaxy Population and its Connection to Transients in the Local and Extragalactic Universe (2021, methodology): “The Gemini image was astrometrically calibrated to match the Gaia DR2 catalog (Gaia Collaboration et al. 2018; Lindegren et al. 2018), with a relative accuracy of 0 2.”
A Catalog of Newly Identified Star Clusters in Gaia DR2 (2019, background): “The uncertainty in ϖ is ∼0.04mas for sources with G< 14mag, 0.1mas for G≈ 17mag, and ∼0.7mas for G≈ 20mag, corresponding to 0.05, 0.2, and 1.2 mas yr−1 of uncertainty in proper motions, respectively (Lindegren et al. 2018).”
The Optical to Mid-infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS, and WISE Surveys (2019, methodology): “Concerning the astrometric content, for the sources with five-parameter astrometric data, the median uncertainty of the parallax is ∼0.04 mas for G<14 mag sources, 0.1 mas at G=17 mag, and 0.7 mas at G=20 mag (Lindegren et al. 2018).”
A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties (2021, background): “For example, the median uncertainties in parallax and pmra (one-dimenstional proper motion) at 𝐺 = 18 have respectively improved from 0.165 mas to 0.120 mas, and from 0.280mas yr−1 to 0.123mas yr−1 (Lindegren et al. 2018, 2020b).”
Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18 (2019, methodology): “Theseclusterdistanceswereobtained by a maximum-likelihood analysis taking into account the systematic parallax uncertainties and the global parallax zero-point offset of −0.029 mas (Lindegren et al. 2018).”