000003742 001__ 3742
000003742 005__ 20190114171846.0
000003742 0247_ $$2DOI$$a10.1051/0004-6361/201833051
000003742 037__ $$aSCART-2019-0026
000003742 100__ $$aGaia Collaboration
000003742 245__ $$a	Gaia Data Release 2. Summary of the contents and survey properties
000003742 260__ $$c2018
000003742 520__ $$aContext. 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 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. 
000003742 594__ $$aNO
000003742 6531_ $$acatalogs
000003742 6531_ $$aastrometry
000003742 6531_ $$atechniques: radial velocities
000003742 6531_ $$astars: fundamental parameters
000003742 6531_ $$astars: variables: general
000003742 6531_ $$aminor planets
000003742 6531_ $$aasteroids: general
000003742 700__ $$aBrown, A. G. A.
000003742 700__ $$aVallenari, A.
000003742 700__ $$aPrusti, T.
000003742 700__ $$ade Bruijne, J. H. J.
000003742 700__ $$aBabusiaux, C.
000003742 700__ $$aBailer-Jones, C. A. L.
000003742 700__ $$aBiermann, M.
000003742 700__ $$aEvans, D. W.
000003742 700__ $$aEyer, L.
000003742 700__ $$aJansen, F.
000003742 700__ $$aJordi, C.
000003742 700__ $$aKlioner, S. A.
000003742 700__ $$aLammers, U.
000003742 700__ $$aLindegren, L.
000003742 700__ $$aLuri, X.
000003742 700__ $$aMignard, F.
000003742 700__ $$aPanem, C.
000003742 700__ $$aPourbaix, D.
000003742 700__ $$aRandich, S.
000003742 700__ $$aSartoretti, P.
000003742 700__ $$aSiddiqui, H. I.
000003742 700__ $$aSoubiran, C.
000003742 700__ $$avan Leeuwen, F.
000003742 700__ $$aWalton, N. A.
000003742 700__ $$aArenou, F.
000003742 700__ $$aBastian, U.
000003742 700__ $$aCropper, M.
000003742 700__ $$aDrimmel, R.
000003742 700__ $$aKatz, D.
000003742 700__ $$aLattanzi, M. G.
000003742 700__ $$aBakker, J.
000003742 700__ $$aCacciari, C.
000003742 700__ $$aCastañeda, J.
000003742 700__ $$aChaoul, L.
000003742 700__ $$aCheek, N.
000003742 700__ $$aDe Angeli, F.
000003742 700__ $$aFabricius, C.
000003742 700__ $$aGuerra, R.
000003742 700__ $$aHoll, B.
000003742 700__ $$aMasana, E.
000003742 700__ $$aMessineo, R.
000003742 700__ $$aMowlavi, N.
000003742 700__ $$aNienartowicz, K.
000003742 700__ $$aPanuzzo, P.
000003742 700__ $$aPortell, J.
000003742 700__ $$aRiello, M.
000003742 700__ $$aSeabroke, G. M.
000003742 700__ $$aTanga, P.
000003742 700__ $$aThévenin, F.
000003742 700__ $$aGracia-Abril, G.
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000003742 700__ $$aAltmann, M.
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000003742 700__ $$aBarstow, M. A.
000003742 700__ $$aBartholomé Muñoz, S.
000003742 700__ $$aBassilana, J.-L.
000003742 700__ $$aBecciani, U.
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000003742 700__ $$aBusonero, D.
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000003742 700__ $$aCarballo, R.
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000003742 700__ $$aCarrasco, J. M.
000003742 700__ $$aCasamiquela, L.
000003742 700__ $$aCastellani, M.
000003742 700__ $$aCastro-Ginard, A.
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000003742 700__ $$aCostigan, G.
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000003742 700__ $$aCrifo, F.
000003742 700__ $$aCrosta, M.
000003742 700__ $$aCrowley, C.
000003742 700__ $$aCuypers, J.
000003742 700__ $$aDafonte, C.
000003742 700__ $$aDamerdji, Y.
000003742 700__ $$aDapergolas, A.
000003742 700__ $$aDavid, P.
000003742 700__ $$aDavid, M.
000003742 700__ $$ade Laverny, P.
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000003742 700__ $$ade Torres, A.
000003742 700__ $$aDebosscher, J.
000003742 700__ $$adel Pozo, E.
000003742 700__ $$aDelbo, M.
000003742 700__ $$aDelgado, A.
000003742 700__ $$aDelgado, H. E.
000003742 700__ $$aDi Matteo, P.
000003742 700__ $$aDiakite, S.
000003742 700__ $$aDiener, C.
000003742 700__ $$aDistefano, E.
000003742 700__ $$aDolding, C.
000003742 700__ $$aDrazinos, P.
000003742 700__ $$aDurán, J.
000003742 700__ $$aEdvardsson, B.
000003742 700__ $$aEnke, H.
000003742 700__ $$aEriksson, K.
000003742 700__ $$aEsquej, P.
000003742 700__ $$aEynard Bontemps, G.
000003742 700__ $$aFabre, C.
000003742 700__ $$aFabrizio, M.
000003742 700__ $$aFaigler, S.
000003742 700__ $$aFalcão, A. J.
000003742 700__ $$aFarràs Casas, M.
000003742 700__ $$aFederici, L.
000003742 700__ $$aFedorets, G.
000003742 700__ $$aFernique, P.
000003742 700__ $$aFigueras, F.
000003742 700__ $$aFilippi, F.
000003742 700__ $$aFindeisen, K.
000003742 700__ $$aFonti, A.
000003742 700__ $$aFraile, E.
000003742 700__ $$aFraser, M.
000003742 700__ $$aFrézouls, B.
000003742 700__ $$aGai, M.
000003742 700__ $$aGalleti, S.
000003742 700__ $$aGarabato, D.
000003742 700__ $$aGarcía-Sedano, F.
000003742 700__ $$aGarofalo, A.
000003742 700__ $$aGarralda, N.
000003742 700__ $$aGavel, A.
000003742 700__ $$aGavras, P.
000003742 700__ $$aGerssen, J.
000003742 700__ $$aGeyer, R.
000003742 700__ $$aGiacobbe, P.
000003742 700__ $$aGilmore, G.
000003742 700__ $$aGirona, S.
000003742 700__ $$aGiuffrida, G.
000003742 700__ $$aGlass, F.
000003742 700__ $$aGomes, M.
000003742 700__ $$aGranvik, M.
000003742 700__ $$aGueguen, A.
000003742 700__ $$aGuerrier, A.
000003742 700__ $$aGuiraud, J.
000003742 700__ $$aGutiérrez-Sánchez, R.
000003742 700__ $$aHaigron, R.
000003742 700__ $$aHatzidimitriou, D.
000003742 700__ $$aHauser, M.
000003742 700__ $$aHaywood, M.
000003742 700__ $$aHeiter, U.
000003742 700__ $$aHelmi, A.
000003742 700__ $$aHeu, J.
000003742 700__ $$aHilger, T.
000003742 700__ $$aHobbs, D.
000003742 700__ $$aHofmann, W.
000003742 700__ $$aHolland, G.
000003742 700__ $$aHuckle, H. E.
000003742 700__ $$aHypki, A.
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000003742 700__ $$aKarampelas, A.
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000003742 700__ $$aKontizas, E.
000003742 700__ $$aKoposov, S. E.
000003742 700__ $$aKordopatis, G.
000003742 700__ $$aKostrzewa-Rutkowska, Z.
000003742 700__ $$aKoubsky, P.
000003742 700__ $$aLambert, S.
000003742 700__ $$aLanza, A. F.
000003742 700__ $$aLasne, Y.
000003742 700__ $$aLavigne, J.-B.
000003742 700__ $$aLe Fustec, Y.
000003742 700__ $$aLe Poncin-Lafitte, C.
000003742 700__ $$aLebreton, Y.
000003742 700__ $$aLeccia, S.
000003742 700__ $$aLeclerc, N.
000003742 700__ $$aLecoeur-Taibi, I.
000003742 700__ $$aLenhardt, H.
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000003742 700__ $$aLiao, S.
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000003742 700__ $$aSegovia, J. C.
000003742 700__ $$aSégransan, D.
000003742 700__ $$aShih, I.-C.
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000003742 700__ $$aSordo, R.
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000003742 700__ $$aTorra Clotet, F.
000003742 700__ $$aTuron, C.
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000003742 700__ $$aVaillant, M.
000003742 700__ $$aValentini, G.
000003742 700__ $$aValette, V.
000003742 700__ $$avan Elteren, A.
000003742 700__ $$aVan Hemelryck, E.
000003742 700__ $$avan Leeuwen, M.
000003742 700__ $$aVaschetto, M.
000003742 700__ $$aVecchiato, A.
000003742 700__ $$aVeljanoski, J.
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000003742 700__ $$aVogt, S.
000003742 700__ $$avon Essen, C.
000003742 700__ $$aVoss, H.
000003742 700__ $$aVotruba, V.
000003742 700__ $$aVoutsinas, S.
000003742 700__ $$aWalmsley, G.
000003742 700__ $$aWeiler, M.
000003742 700__ $$aWertz, O.
000003742 700__ $$aWevers, T.
000003742 700__ $$aWyrzykowski, Ł.
000003742 700__ $$aYoldas, A.
000003742 700__ $$aŽerjal, M.
000003742 700__ $$aZiaeepour, H.
000003742 700__ $$aZorec, J.
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000003742 700__ $$aZucker, S.
000003742 700__ $$aZurbach, C.
000003742 700__ $$aZwitter, T.
000003742 773__ $$cA1, 22 pp$$pAstronomy & Astrophysics$$v616$$y2018
000003742 8560_ $$fronny.blomme@observatoire.be
000003742 85642 $$ahttp://adsabs.harvard.edu/abs/2018A%26A...616A...1G
000003742 905__ $$apublished in
000003742 980__ $$aREFERD