Gaia Data Release 2

Summary of the contents and survey properties

¹ Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
² INAF - Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova, Italy
³ Science Support Office, Directorate of Science, European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201AZ, Noordwijk, The Netherlands
⁴ GEPI, Observatoire de Paris, Université PSL, CNRS, 5 Place Jules Janssen, 92190 Meudon, France
⁵ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁶ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁷ Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
⁸ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁹ Department of Astronomy, University of Geneva, Chemin des Maillettes 51, 1290 Versoix, Switzerland
¹⁰ Mission Operations Division, Operations Department, Directorate of Science, European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
¹¹ Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain
¹² Lohrmann Observatory, Technische Universität Dresden, Mommsenstraße 13, 01062 Dresden, Germany
¹³ European Space Astronomy Centre (ESA/ESAC), Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹⁴ Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden
¹⁵ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice Cedex 4, France
¹⁶ CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹⁷ Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles CP 226, Boulevard du Triomphe, 1050 Brussels, Belgium
¹⁸ F.R.S.-FNRS, Rue d’Egmont 5, 1000 Brussels, Belgium
¹⁹ INAF - Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
²⁰ Telespazio Vega UK Ltd for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
²¹ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
²² Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
²³ INAF - Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
²⁴ INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, via Piero Gobetti 93/3, 40129 Bologna, Italy
²⁵ Serco Gestión de Negocios for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
²⁶ ALTEC, Corso Marche 79, 10146 Torino, Italy
²⁷ Department of Astronomy, University of Geneva, Chemin d’Ecogia 16, 1290 Versoix, Switzerland
²⁸ Gaia DPAC Project Office, ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
²⁹ SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l?Observatoire, 75014 Paris, France
³⁰ National Observatory of Athens, I. Metaxa and Vas. Pavlou, Palaia Penteli, 15236 Athens, Greece
³¹ IMCCE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Lille, 77 av. Denfert-Rochereau, 75014 Paris, France
³² Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
³³ Institut d’Astrophysique Spatiale, Université Paris XI, UMR 8617, CNRS, Bâtiment 121, 91405, Orsay Cedex, France
³⁴ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
³⁵ Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
³⁶ Institut d’Astrophysique et de Géophysique, Université de Liège, 19c, Allée du 6 Août, 4000 Liège, Belgium
³⁷ ATG Europe for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
³⁸ Área de Lenguajes y Sistemas Informáticos, Universidad Pablo de Olavide, Ctra. de Utrera, km. 1, 41013 Sevilla, Spain
³⁹ ETSE Telecomunicación, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Galicia, Spain
⁴⁰ Large Synoptic Survey Telescope, 950 N. Cherry Avenue, Tucson AZ 85719, USA
⁴¹ Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, 67000 Strasbourg, France
⁴² Kavli Institute for Cosmology, University of Cambridge, Madingley Road, CB3 0HA, UK
⁴³ Aurora Technology for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁴⁴ Laboratoire Univers et Particules de Montpellier, Université Montpellier, Place Eugène Bataillon, CC72, 34095 Montpellier Cedex 05, France
⁴⁵ Department of Physics and Astronomy, Division of Astronomy and Space Physics, Uppsala University, Box 516, 75120 Uppsala, Sweden
⁴⁶ CENTRA, Universidade de Lisboa, FCUL, Campo Grande, Edif. C8, 1749-016 Lisboa, Portugal
⁴⁷ Università di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, 95123 Catania, Italy
⁴⁸ INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy
⁴⁹ University of Vienna, Department of Astrophysics, Türkenschanz- straße 17, 1180 Vienna, Austria
⁵⁰ CITIC - Department of Computer Science, University of A Coruña, Campus de Elviña s/n, 15071 A Coruña, Spain
⁵¹ CITIC - Astronomy and Astrophysics, University of A Coruña, Campus de Elviña s/n, 15071 A Coruña, Spain
⁵² INAF - Osservatorio Astronomico di Roma, Via di Frascati 33, 00078 Monte Porzio Catone (Roma), Italy
⁵³ Space Science Data Center - ASI, Via del Politecnico SNC, 00133 Roma, Italy
⁵⁴ University of Helsinki, Department of Physics, PO Box 64, 00014 Helsinki, Finland
⁵⁵ Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, 02430 Masala, Finland
⁵⁶ Isdefe for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁵⁷ Institut UTINAM UMR6213, CNRS, OSU THETA Franche-Comté Bourgogne, Université Bourgogne Franche-Comté, 25000 Besançon, France
⁵⁸ STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, UK
⁵⁹ Departamento de Inteligencia Artificial, UNED, c/ Juan del Rosal 16, 28040 Madrid, Spain
⁶⁰ Elecnor Deimos Space for ESA/ESAC, Camino bajo del Castillo s/n Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁶¹ Thales Services for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁶² Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
⁶³ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
⁶⁴ ON/MCT, Rua Gal. José Cristino 77, Rio de Janeiro 20921-400, Brazil
⁶⁵ OV/UFRJ, Ladeira Pedro Antônio 43, Rio de Janeiro 20080-090, Brazil
⁶⁶ Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA
⁶⁷ Università di Torino, Dipartimento di Fisica, via Pietro Giuria 1, 10125 Torino, Italy
⁶⁸ Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESA-ESAC, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
⁶⁹ Leicester Institute of Space and Earth Observation and Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
⁷⁰ Departamento de Estadística, Universidad de Cádiz, Calle República Árabe Saharawi s/n, 11510 Puerto Real, Cádiz, Spain
⁷¹ Astronomical Institute Bern University, Sidlerstrasse5, 3012 Bern, Switzerland (present address)
⁷² EURIX Srl, Corso Vittorio Emanuele II 61, 10128 Torino, Italy
⁷³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
⁷⁴ HE Space Operations BV for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁷⁵ Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
⁷⁶ SISSA - Scuola Internazionale Superiore di Studi Avanzati, via Bonomea 265, 34136 Trieste, Italy
⁷⁷ University of Turin, Department of Computer Sciences, Corso Svizzera 185, 10149 Torino, Italy
⁷⁸ SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584CA Utrecht, The Netherlands
⁷⁹ Departamento de Matemática Aplicada y Ciencias de la Computación, Univ. de Cantabria, ETS Ingenieros de Caminos, Canales y Puertos, Avda. de los Castros s/n, 39005 Santander, Spain
⁸⁰ Unidad de Astronomía, Universidad de Antofagasta, Avenida Angamos 601, Antofagasta 1270300, Chile
⁸¹ CRAAG - Centre de Recherche en Astronomie, Astrophysique et Géophysique, Route de l’Observatoire, Bp 63, Bouzareah 16340, Alger, Algeria
⁸² University of Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, 2020 Antwerp, Belgium
⁸³ INAF - Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini, 64100 Teramo, Italy
⁸⁴ INAF - Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
⁸⁵ Instituto de Astronomia, Geofìsica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitaria, 05508-900 São Paulo, Brazil
⁸⁶ Department of Astrophysics, Astronomy and Mechanics, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, 15783 Athens, Greece
⁸⁷ Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
⁸⁸ RHEA for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁸⁹ ATOS for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁹⁰ School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
⁹¹ UNINOVA - CTS, Campus FCT-UNL, Monte da Caparica, 2829-516 Caparica, Portugal
⁹² School of Physics, O’Brien Centre for Science North, University College Dublin, Belfield, Dublin 4, Ireland
⁹³ Dipartimento di Fisica e Astronomia, Università di Bologna, Via Piero Gobetti 93/2, 40129 Bologna, Italy
⁹⁴ Barcelona Supercomputing Center - Centro Nacional de Supercomputación, c/ Jordi Girona 29, Ed. Nexus II, 08034 Barcelona, Spain
⁹⁵ Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Box 848, S-981 28 Kiruna, Sweden
⁹⁶ Max Planck Institute for Extraterrestrial Physics, High Energy Group, Gießenbachstraße, 85741 Garching, Germany
⁹⁷ Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland
⁹⁸ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, 1121 Budapest, Hungary
⁹⁹ Eötvös Loránd University, Egyetem tér 1-3, 1053 Budapest, Hungary
¹⁰⁰ American Community Schools of Athens, 129 Aghias Paraskevis Ave. & Kazantzaki Street, Halandri, 15234 Athens, Greece
¹⁰¹ Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
¹⁰² Villanova University, Department of Astrophysics and Planetary Science, 800 E Lancaster Avenue, Villanova PA 19085, USA
¹⁰³ Physics Department, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
¹⁰⁴ McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
¹⁰⁵ Astronomical Institute, Academy of Sciences of the Czech Republic, Fričova 298, 25165 Ondřejov, Czech Republic
¹⁰⁶ Telespazio for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹⁰⁷ Institut de Physique de Rennes, Université de Rennes 1, 35042 Rennes, France
¹⁰⁸ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Rd, 200030 Shanghai, PR China
¹⁰⁹ School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, PR China
¹¹⁰ Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark
¹¹¹ DXC Technology, Retortvej 8, 2500 Valby, Denmark
¹¹² Las Cumbres Observatory, 6740 Cortona Drive Suite 102, Goleta, CA 93117, USA
¹¹³ Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
¹¹⁴ Baja Observatory of University of Szeged, Szegedi út III/70, 6500 Baja, Hungary
¹¹⁵ Laboratoire AIM, IRFU/Service d’Astrophysique - CEA/DSM - CNRS - Université Paris Diderot, Bât 709, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France
¹¹⁶ Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
¹¹⁷ Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic
¹¹⁸ AKKA for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹¹⁹ Vitrociset Belgium for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹²⁰ HE Space Operations BV for ESA/ESTEC, Keplerlaan 1, 2201AZ Noordwijk, The Netherlands
¹²¹ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹²² QUASAR Science Resources for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹²³ Fork Research, Rua do Cruzado Osberno, Lt. 1, 9 esq., Lisboa, Portugal
¹²⁴ APAVE SUDEUROPE SAS for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹²⁵ Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, 38711 Breña Baja, Spain
¹²⁶ Spanish Virtual Observatory, Spain
¹²⁷ Fundación Galileo Galilei - INAF, Rambla José Ana Fernández Pérez 7, 38712 Breña Baja, Santa Cruz de Tenerife, Spain
¹²⁸ INSA for ESA/ESAC, Camino bajo del Castillo s/n, Urbanizaciòn Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹²⁹ Departamento de Arquitectura de Computadores y Automática, Facultad de Informática, Universidad Complutense de Madrid, C/ Prof. José García Santesmases s/n, 28040 Madrid, Spain
¹³⁰ H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
¹³¹ Institut d’Estudis Espacials de Catalunya (IEEC), Gran Capitá 2-4, 08034 Barcelona, Spain
¹³² Applied Physics Department, Universidade de Vigo, 36310 Vigo, Spain
¹³³ Stellar Astrophysics Centre, Aarhus University, Department of Physics and Astronomy, 120 Ny Munkegade, Building 1520, 8000 Aarhus C, Denmark
¹³⁴ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
¹³⁵ Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia
¹³⁶ Sorbonne Universités, UPMC Univ. Paris 6 et CNRS, UMR 7095, Institut d’Astrophysique de Paris, 98 bis bd. Arago, 75014 Paris, France
¹³⁷ Department of Geosciences, Tel Aviv University, Tel Aviv 6997801, Israel

Received: 19 March 2018
Accepted: 14 April 2018

Abstract

Context. We present the second Gaia data release, Gaia DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system.

Aims. A summary of the contents of Gaia DR2 is presented, accompanied by a discussion on the differences with respect to Gaia DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of Gaia DR2 results.

Methods. The raw data collected with the Gaia instruments during the first 22 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to Gaia DR1 in terms of completeness, performance, and richness of the data products. Results. Gaia DR2 contains celestial positions and the apparent brightness in G for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0.5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the G_BP (330–680 nm) and G_RP (630–1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally, Gaia DR2 also represents a new materialisation of the celestial reference frame in the optical, the Gaia-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to Gaia DR1, and we stress the need to consider the two data releases as independent. Conclusions. Gaia DR2 represents a major achievement for the Gaia mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the Gaia survey which covers a very substantial fraction of the volume of our galaxy.