Correction to the Photometric Colors of Gaia Early Data Release 3

Abstract

In this work, we use the spectroscopy-based stellar color regression method with ∼0.7 million common stars between LAMOST DR7 and Gaia EDR3 to acquire color corrections in G − G RP and G BP − G RP . A sub-millimagnitude precision is achieved. Our results demonstrate that improvements in the calibration process of the EDR3 have removed the color term in G BP − G RP and eliminated the discontinuity caused by the changes of instrument configurations to a great extent. However, modest systematic trends with G magnitude are still detected. The corresponding color correction terms as a function of G are provided for 9.5 mag < G < 17.5 mag and compared with other determinations. We conclude that the corrections given in this work are particularly suited for cases where the color–color investigations are required, while for color–magnitude investigations other corrections may be better owing to systematics with reddening. Possible applications of our results are discussed.