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Gaia Early Data Release 3 : Acceleration of the Solar System from Gaia astrometry

Klioner, S. A. ; Mignard, F. ; Lindegren, L. LU orcid ; Bastian, U. ; McMillan, P. J. LU orcid ; Hernández, J. ; Hobbs, D. LU orcid ; Ramos-Lerate, M. ; Biermann, M. and Bombrun, A. , et al. (2021) In Astronomy and Astrophysics 649.
Abstract

Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions... (More)

Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate. Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 ± 0.16) × 10-10 m s-2 (or 7.33 ±0.51 km s-1 Myr-1) towards α = 269.1° ± 5.4°, δ = -31.6° ± 4.1°, corresponding to a proper motion amplitude of 5.05 ±0.35 μas yr-1. This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 μas yr-1.

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Contribution to journal
publication status
published
subject
keywords
Astrometry, Galaxy: kinematics and dynamics, Methods: data analysis, Proper motions, Reference systems
in
Astronomy and Astrophysics
volume
649
article number
A9
publisher
EDP Sciences
external identifiers
  • scopus:85104986773
ISSN
0004-6361
DOI
10.1051/0004-6361/202039734
language
English
LU publication?
yes
id
a698503e-398e-4dc0-be24-8f37e8f7e043
date added to LUP
2021-05-10 15:37:40
date last changed
2023-01-01 06:03:45
@article{a698503e-398e-4dc0-be24-8f37e8f7e043,
  abstract     = {{<p>Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate. Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 ± 0.16) × 10-10 m s-2 (or 7.33 ±0.51 km s-1 Myr-1) towards α = 269.1° ± 5.4°, δ = -31.6° ± 4.1°, corresponding to a proper motion amplitude of 5.05 ±0.35 μas yr-1. This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 μas yr-1. </p>}},
  author       = {{Klioner, S. A. and Mignard, F. and Lindegren, L. and Bastian, U. and McMillan, P. J. and Hernández, J. and Hobbs, D. and Ramos-Lerate, M. and Biermann, M. and Bombrun, A. and De Torres, A. and Gerlach, E. and Geyer, R. and Hilger, T. and Lammers, U. and Steidelmüller, H. and Stephenson, C. A. and Brown, A. G.A. and Vallenari, A. and Prusti, T. and De Bruijne, J. H.J. and Babusiaux, C. and Creevey, O. L. and Evans, D. W. and Eyer, L. and Hutton, A. and Jansen, F. and Jordi, C. and Luri, X. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Soubiran, C. and Walton, N. A. and Arenou, F. and Bailer-Jones, C. A.L. and Cropper, M. and Drimmel, R. and Katz, D. and Lattanzi, M. G. and Nicolas, C. and Davidson, M. and Holl, B. and Smith, M. and Álvarez, M. A. and Anderson, R. I. and Baker, S. G. and Mastrobuono-Battisti, A. and Taylor, M. B.}},
  issn         = {{0004-6361}},
  keywords     = {{Astrometry; Galaxy: kinematics and dynamics; Methods: data analysis; Proper motions; Reference systems}},
  language     = {{eng}},
  month        = {{05}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{Gaia Early Data Release 3 : Acceleration of the Solar System from Gaia astrometry}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202039734}},
  doi          = {{10.1051/0004-6361/202039734}},
  volume       = {{649}},
  year         = {{2021}},
}