<i>Gaia</i> Data Release 2
L. LindegrenLund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, SwedenJesús HernándezESA, European Space Astronomy Centre, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainA. BombrunHE Space Operations BV for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainS. A. KlionerLohrmann-Observatorium, Technische Universität Dresden, Mommsenstrasse 13, 01062 Dresden, GermanyU. BastianAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyM. Ramos-LerateA. de TorresHE Space Operations BV for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainH. SteidelmüllerLohrmann-Observatorium, Technische Universität Dresden, Mommsenstrasse 13, 01062 Dresden, GermanyC. A. StephensonTelespazio Vega UK Ltd for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainD. HobbsLund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, SwedenU. LammersESA, European Space Astronomy Centre, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. BiermannAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyR. GeyerLohrmann-Observatorium, Technische Universität Dresden, Mommsenstrasse 13, 01062 Dresden, GermanyT. HilgerLohrmann-Observatorium, Technische Universität Dresden, Mommsenstrasse 13, 01062 Dresden, GermanyDaniel MichalikLund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, SwedenU. StampaAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyP. J. McMillanLund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, SwedenJ. CastañedaInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainM. ClotetInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainG. ComorettoTelespazio Vega UK Ltd for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. DavidsonInstitute for Astronomy, School of Physics and Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UKC. FabriciusInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainG. GraciaGaia Project Office for DPAC/ESA, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainN. C. HamblyInstitute for Astronomy, School of Physics and Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UKA. HuttonAurora Technology for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainA. MoraAurora Technology for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainJ. PortellInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainF. van LeeuwenInstitute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UKU. AbbasIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyA. AbreuElecnor Deimos Space for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. AltmannAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyA. H. AndreiE. AngladaSerco for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainL. Balaguer-NúñezInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainC. BaracheSYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’Observatoire, 75014 Paris, FranceU. BeccianiINAF, Osservatorio Astrofisico di Catania, Catania, ItalyS. BertoneAstronomical Institute, Bern University, Sidlerstrasse 5, 3012 Bern, SwitzerlandL. BianchiEURIX SRL, Corso Vittorio Emanuele II, 61, 10128 Torino, ItalyS. BouquillonSYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’Observatoire, 75014 Paris, FranceG. BourdaLaboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, FranceT. BrüsemeisterAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyB. BucciarelliIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyD. BusoneroIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyR. BuzziIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyR. CancelliereUniversity of Torino, Department of Computer Science, Torino, ItalyT. CarlucciSYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’Observatoire, 75014 Paris, FranceP. CharlotLaboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, FranceN. CheekSerco for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. CrostaIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyC. CrowleyHE Space Operations BV for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainJ. H. J. de BruijneESA, European Space Research and Technology Centre, Keplerlaan 1, 2200 AG, Noordwijk, The NetherlandsF. de FeliceUniversity of Padova, Via Marzolo 8, Padova 35131, ItalyR. DrimmelIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyP. EsquejRHEA for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainA. FiengaUniversité Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Géo Azur, 250 rue Albert Einstein, CS 10269, 06905 Sophia Antipolis Cedex, FranceE. FraileRHEA for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. GaiIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyN. GarraldaInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainJ. J. González-VidalInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainR. GuerraESA, European Space Astronomy Centre, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. HäuserAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyWilfried HofmannAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyB. HollObservatoire Astronomique de l’Université de Genève, Sauverny, Chemin des Maillettes 51, 1290 Versoix, SwitzerlandS. JordanAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyM. G. LattanziIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyH. LenhardtAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyS. LiaoIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyE. LicataEURIX SRL, Corso Vittorio Emanuele II, 61, 10128 Torino, ItalyTim ListerLas Cumbres Observatory, 6740 Cortona Dr. 102, Goleta, CA 93117, USAW. LöfflerAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 14, 69120 Heidelberg, GermanyJ. M. MarchantAstrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UKJ Martín-FleitasAurora Technology for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainR. MessineoF. MignardUniversité Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice Cedex 4, FranceR. MorbidelliIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyE. PoggioIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyA. RivaIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyN. RowellInstitute for Astronomy, School of Physics and Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UKE. SalgueroATG for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainM. SarassoIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyEva SciaccaINAF, Osservatorio Astrofisico di Catania, Catania, ItalyH. I. SiddiquiTelespazio Vega UK Ltd for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainR. L. SmartIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyA. SpagnaIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, ItalyI. A. SteeleAstrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UKF. TarisSorbonne UniversitéJ. TorraInstitut de Ciències del Cosmos, Universitat de Barcelona (ICCUB), Martí Franquès 1, 08028 Barcelona, SpainA. van ElterenSterrewacht Leiden, Leiden University, PO Box 9513, 2300 RA, Leiden, The NetherlandsW. van ReevenAurora Technology for ESA/ESAC, Camino Bajo del Castillo s/n, 28691 Villanueva de la Cañada, SpainAlberto VecchiatoIstituto Nazionale di Astrofisica, Osservatorio Astrofisico di Torino, Via Osservatorio 20, Pino Torinese, Torino 10025, Italy
2018en
ABI
Abstract
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.
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Citations and references
Cited by 20 references