Oral Presentation

Forward-modelling Stage IV galaxy surveys for precise cosmological measurements

Author(s): Luca Tortorelli (LMU Munich)

Presenter: Luca Tortorelli (LMU Munich)

Stage IV experiments are set to provide the stringent constraints ever on the cosmological parameters that describe the large scale structure. However, to achieve this aim, we need careful control of the systematics, especially those related to the accurate knowledge of the tomographic redshift distributions. The forward-modelling of photometric and spectroscopic galaxy surveys, a method that bridges cosmology with galaxy evolution, is arising as one of the most promising approaches to solve the problem of accurate galaxy redshift distribution estimates. In this talk I will discuss the past (Tortorelli+18,20,21) and on-going efforts (Tortorelli+24, Tortorelli+25) in forward-modelling galaxy surveys, from the modelling of the galaxy population (GalSBI) to the simulation of images (UFig) and spectra (USpec), as well as the data required to calibrate this model. I'll show that our forward-modelling framework already provides precise redshift distribution estimates for Stage-III setup and that the inclusion of constraining spectroscopic data in the modelling will lead to the precision required by Stage IV surveys.