The flux calibration of Gaia

TL;DR

This paper details the Gaia mission's calibration process, emphasizing the importance of external calibration for accurate measurements, and describes the spectrophotometric standard stars survey and calibration model used.

Contribution

It introduces a detailed calibration model for Gaia that uses a grid of standard stars calibrated to Vega, enhancing measurement accuracy.

Findings

Calibration model achieves a few percent accuracy

Standard star grid covers diverse spectral types

External calibration is essential despite self-calibration capabilities

Abstract

The Gaia mission is described, along with its scientific potential and its updated science perfomances. Although it is often described as a self-calibrated mission, Gaia still needs to tie part of its measurements to external scales (or to convert them in physical units). A detailed decription of the Gaia spectrophotometric standard stars survey is provided, along with a short description of the Gaia calibration model. The model requires a grid of approximately 200 stars, calibrated to a few percent with respect to Vega, and covering different spectral types.