Research Division Seminar
From precision to accuracy cosmology: dealing with systematic effects in LSST

Abstract

With the arrival of large galaxy surveys such as KiDS, DES or HSC and their ability to observe millions of galaxies, statistical errors have shrunk, making cosmology a precision science. Now, systematic effects are becoming the main source of uncertainty, so dealing with them will be one of the main challenges that next-generation surveys, such as Euclid, DESI or LSST. In this presentation, we will focus on two sources of systematic uncertainty: observational systematics and atmospheric conditions. For the former, we will explore the methods and lessons learnt from the DES-Y3 galaxy clustering analysis, the ongoing work for Y6 and the prospects for LSST-DESC. For the latter, we will introduce LSST’s Auxiliary Telescope (AuxTel), whose purpose is to measure atmospheric transparency and to derive color corrections based on spectroscopic observations.