Volume 649, May 2021
|Number of page(s)||7|
|Section||Celestial mechanics and astrometry|
|Published online||26 May 2021|
Characterizing and correcting the proper motion bias of the bright Gaia EDR3 sources
Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB),
Martí i Franquès 1,
2 Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
Accepted: 15 April 2021
In this paper, we characterize magnitude-dependent systematics in the proper motions of the Gaia EDR3 catalog and provide a prescription for their removal. The reference frame of bright stars (G ≲ 13) in EDR3 is known to rotate with respect to extragalactic objects, but this rotation has proven difficult to characterize and correct. We employ a sample of binary stars and a sample of open cluster members to characterize this proper motion bias as a magnitude-dependent spin of the reference frame. We show that the bias varies with G magnitude, reaching up to 80 μas yr−1 for sources in the range G = 11–13, several times the formal EDR3 proper motion uncertainties. We also show evidence for an additional dependence on the color of the source, with a magnitude up to ~10 μas yr−1. However, a color correction proportional to the effective wavenumber is unsatisfactory for very red or very blue stars, and we do not recommend its use. We provide a recipe for a magnitude-dependent correction to align the proper motion of the Gaia EDR3 sources brighter than G = 13 with the International Celestial Reference Frame.
Key words: astrometry / proper motions / methods: data analysis / methods: statistical
© ESO 2021
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.