A compilation of known QSOs for the Gaia mission

TL;DR

This paper compiles a comprehensive catalog of over 1.84 million quasars, including nearly 800,000 in Gaia DR1, to aid Gaia's astrometric calibration and celestial reference frame construction.

Contribution

It provides the largest known quasar catalog tailored for Gaia, enhancing astrometric accuracy and reference frame stability.

Findings

Catalog contains 1,843,850 quasars with 797,632 in Gaia DR1.

The catalog supports Gaia's astrometric bias detection and reference frame creation.

Provides a reliable resource for Gaia mission calibration.

Abstract

Quasars are essential for astrometric in the sense that they are spatial stationary because of their large distance from the Sun. The European Space Agency (ESA) space astrometric satellite Gaia is scanning the whole sky with unprecedented accuracy up to a few muas level. However, Gaia's two fields of view observations strategy may introduce a parallax bias in the Gaia catalog. Since it presents no significant parallax, quasar is perfect nature object to detect such bias. More importantly, quasars can be used to construct a Celestial Reference Frame in the optical wavelengths in Gaia mission. In this paper, we compile the most reliable quasars existing in literatures. The final compilation (designated as Known Quasars Catalog for Gaia mission, KQCG) contains 1843850 objects, among of them, 797632 objects are found in Gaia DR1 after cross-identifications. This catalog will be very useful in Gaia mission.