How in situ atmospheric transmission can affect cosmological constraints from type Ia supernovae ?

TL;DR

Accurate in situ atmospheric transmission measurements are crucial for reducing photometric uncertainties in large supernova surveys, thereby improving cosmological constraints.

Contribution

This paper demonstrates how local atmospheric transmission measurements can correct supernova photometry and details its implementation at the Rubin Observatory.

Findings

Measuring atmospheric transmission reduces photometric systematic uncertainties.

Implementation of atmospheric correction at Rubin Observatory improves magnitude accuracy.

Enhanced calibration supports more precise cosmological parameter estimation.

Abstract

The measurement of type Ia supernova colours in photometric surveys is the key to access to cosmological distances. But for future large surveys like the Large Survey of Space and Time undertaken by the Vera Rubin Observatory in Chile, the large statistical power of the promised catalogues will make the photometric calibration uncertainties dominant in the error budget and will limit our ability to use it for precision cosmology. The knowledge of the on-site atmospheric transmission on average for the full survey, or for season or each exposure can help reaching the sub-percent precision for magnitudes. We will show that measuring the local atmospheric transmission allows to correct the raw magnitudes to reduce the photometric systematic uncertainties. Then we will present how this strategy is implemented at the Rubin Observatory via the Auxiliary Telescope and its slitless spectrograph.