Please use this identifier to cite or link to this item:
Title: Gaia Data Release 2: Summary of the contents and survey properties
Author: Gaia Collaboration
Castañeda Pons, Javier Bernardo
Jordi i Nebot, Carme
Luri Carrascoso, Xavier
Antoja Castelltort, M. Teresa
Romero Gómez, Mercè
Fabricius, Claus
Masana Fresno, Eduard
Portell i de Mora, Jordi
Clotet Altarriba, Marcial
Torra Roca, Jorge
Antiche Garzón, Erika
Balaguer Núñez, María de los Dolores
Borrachero, Raúl
Cantat Gaudin, Tristan
Carrasco Martínez, José Manuel
Casamiquela Floriach, Laia
Castro Ginard, Alfred
Farras Casas, Martí
Julbe, Francesc
Mor Crespo, Roger
Torra Clotet, Ferran
Voss, Hölger
González Vidal, Juan José
Garralda Torre, Nora
Molina Martínez, Daniel
Keywords: Astrometria
Catàlegs d'estels
Star catalogs
Issue Date: 10-Aug-2018
Publisher: EDP Sciences
Abstract: Context. We present the second Gaiadata 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 GBP (330-680 nm) and GRP (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.
Note: Reproducció del document publicat a:
It is part of: Astronomy & Astrophysics, 2018, vol. 616, num. A1
Related resource:
ISSN: 0004-6361
Appears in Collections:Articles publicats en revistes (Física Quàntica i Astrofísica)

Files in This Item:
File Description SizeFormat 
679977.pdf11.61 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.