Atomic oscillator strengths in the spectral domain of Gaia

This paper presents the results of a detailed investigation of the validity of oscillator strengths in the spectral domain of the Gaia spectrometer 848-875 nm. This analysis is performed by fitting the most significant Fe I and Si I solar lines in this spectral range with synthetic profiles calculated by 3D radiative hydrodynamical (RHD) simulations. Our main conclusion is that the laboratory oscillator strengths agree well (< 0.1 dex) with values derived from 3D simulations, whereas the semi-empirical values found in data bases like the Vienna Atomic Line Database are imprecise, with a disagreement that can be as large as 1 dex. We address this conclusion to laboratories to encourage new oscillator strength measurements in the infrared, especially in the Gaia region.