Gaia Data Release 2 - The astrometric solution

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 u...

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Autores: Gaia Collaboration, Castañeda Pons, Javier Bernardo, Clotet Altarriba, Marcial, Fabricius, Claus, Portell i de Mora, Jordi, Balaguer Núñez, María de los Dolores, Garralda Torre, Nora, González Vidal, Juan José, Torra Roca, Jorge
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2018
País:España
Recursos:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/140841
Acesso em linha:https://hdl.handle.net/2445/140841
Access Level:acceso abierto
Palavra-chave:Astrometria
Paral·laxi
Astrometry
Parallax
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spelling Gaia Data Release 2 - The astrometric solutionGaia CollaborationCastañeda Pons, Javier BernardoClotet Altarriba, MarcialFabricius, ClausPortell i de Mora, JordiBalaguer Núñez, María de los DoloresGarralda Torre, NoraGonzález Vidal, Juan JoséTorra Roca, JorgeAstrometriaParal·laxiAstrometryParallaxContext. 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 results performed 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 mas at G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr1, 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 yr1. 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 yr1 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.EDP Sciences2019201920182019info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion25 p.application/pdfhttps://hdl.handle.net/2445/140841Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB))reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésReproducció del document publicat a: https://doi.org/10.1051/0004-6361/201832727Astronomy & Astrophysics, 2018, vol. 616, num. A2https://doi.org/10.1051/0004-6361/201832727(c) The European Southern Observatory (ESO), 2018info:eu-repo/semantics/openAccessoai:recercat.cat:2445/1408412026-05-29T05:05:01Z
dc.title.none.fl_str_mv Gaia Data Release 2 - The astrometric solution
title Gaia Data Release 2 - The astrometric solution
spellingShingle Gaia Data Release 2 - The astrometric solution
Gaia Collaboration
Astrometria
Paral·laxi
Astrometry
Parallax
title_short Gaia Data Release 2 - The astrometric solution
title_full Gaia Data Release 2 - The astrometric solution
title_fullStr Gaia Data Release 2 - The astrometric solution
title_full_unstemmed Gaia Data Release 2 - The astrometric solution
title_sort Gaia Data Release 2 - The astrometric solution
dc.creator.none.fl_str_mv Gaia Collaboration
Castañeda Pons, Javier Bernardo
Clotet Altarriba, Marcial
Fabricius, Claus
Portell i de Mora, Jordi
Balaguer Núñez, María de los Dolores
Garralda Torre, Nora
González Vidal, Juan José
Torra Roca, Jorge
author Gaia Collaboration
author_facet Gaia Collaboration
Castañeda Pons, Javier Bernardo
Clotet Altarriba, Marcial
Fabricius, Claus
Portell i de Mora, Jordi
Balaguer Núñez, María de los Dolores
Garralda Torre, Nora
González Vidal, Juan José
Torra Roca, Jorge
author_role author
author2 Castañeda Pons, Javier Bernardo
Clotet Altarriba, Marcial
Fabricius, Claus
Portell i de Mora, Jordi
Balaguer Núñez, María de los Dolores
Garralda Torre, Nora
González Vidal, Juan José
Torra Roca, Jorge
author2_role author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Astrometria
Paral·laxi
Astrometry
Parallax
topic Astrometria
Paral·laxi
Astrometry
Parallax
description 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 results performed 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 mas at G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr1, 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 yr1. 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 yr1 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.
publishDate 2018
dc.date.none.fl_str_mv 2018
2019
2019
2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/140841
url https://hdl.handle.net/2445/140841
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.1051/0004-6361/201832727
Astronomy & Astrophysics, 2018, vol. 616, num. A2
https://doi.org/10.1051/0004-6361/201832727
dc.rights.none.fl_str_mv (c) The European Southern Observatory (ESO), 2018
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) The European Southern Observatory (ESO), 2018
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 25 p.
application/pdf
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB))
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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