RT journal article
T1 Gaia Early Data Release 3 The celestial reference frame (Gaia-CRF3)
A1 Klioner, S. A.
A1 Lindegren, L.
A1 Mignard, F.
A1 Hernández, J.
A1 Ramos Lerate, M.
A1 Berihuete Macías, Ángel
A2 Estadística e Investigación Operativa
K1 astrometry
K1 reference systems
K1 proper motions
K1 catalogs
K1 quasars: general
AB Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaiamission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame isdefined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue.Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometricquality.Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues ofquasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants.Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random andsystematic errors in the proper motions are analysed, as well as the radio–optical offsets in position for sources in the third realisationof the International Celestial Reference Frame (ICRF3).Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutionsin Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13–21 with a peak densityat 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of12 µas yr−1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands,the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline thefuture of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extractinformation about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of anastrometric solution.
PB EDP Sciences
SN 0004-6361
YR 2022
FD 2022-04-15
LK http://hdl.handle.net/10498/32137
UL http://hdl.handle.net/10498/32137
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 11-nov-2026