Orateur
Description
The Auxiliary telescope (AuxTel) of the Rubin Observatory is a spectrometer that precisely characterizes the atmosphere during LSST observation. Observing standard stars and comparing the resulting spectra with out-of-atmosphere CALSPEC spectra gives the whole atmospheric transmission curve. This procedure is performed with a forward modeling software called Spectractor, which is implemented in the main LSST pipeline. In particular, the water content of the atmosphere (PWV) can have a significant impact on the magnitude of the redder LSST bands (i, z, y) and thus on high-redshift supernovae. The CALSPEC star catalog does not cover the full LSST sky, especially for deep drilling fields (DDFs). I will present the use of the GAIA star spectra catalog for AuxTel. We tested the performance of Spectractor with GAIA standards on the available dataset, showing an unbiased determination of PWV. We created a dedicated GAIA source catalog that is optimal for AuxTel and the following of DDF fields. Finally, we derived a correction of the GAIA spectra by directly comparing the CALSPEC/GAIA catalogs. This correction drastically improved the capacity of AuxTel to determine the atmospheric ozone content with GAIA.
