Validation and Spin of the Bright Part of Gaia DR2 and DR3

Abstract

ABSTRACT The Gaia Data Release 3 (DR3) is an important step in the realization of the future Gaia reference frame. Ideally, across G magnitudes from 3 to 21, the Gaia DR2 and DR3 objects with their positions (, ) and proper motions (, ) should be expressed in a nonrotating reference frame relative to distant extragalactic sources (mostly quasars—QSOs) and in accordance with the International Celestial Reference System (ICRS). There are comparison data for mag objects using Gaia's observations of QSOs, but it is not possible for brighter objects. The QSOs are faint objects in optical domain (just small amount of QSOs for mag) and the validation of the bright part of Gaia reference frame is difficult. We did it and investigated a spin of the indicated rotation of the Gaia bright star reference frame. It is mas year −1 from the other papers. We determined two spin components (, ) of the Gaia bright star reference frame (DR2 and DR3) using our original GD catalog of of 1653 stars. The original data help to avoid spin in the Gaia bright star reference frame.