COLLOQUIUM Dr. Luca Tortorelli, LMU

Forward-modelling galaxy surveys for next-generation cosmological and galaxy population measurements

We are entering a transformative era for cosmology and galaxy evolution, driven by wide-field photometric and spectroscopic galaxy surveys that will map a significant fraction of the observable Universe at an unprecedented volume and depth. These surveys will measure positions, magnitude, and shape for billions of objects, and redshifts for tens of millions of them, leading to a regime where the statistical uncertainties of the measurements are sub-dominant compared to the systematics ones. For both cosmology and galaxy population studies, the accurate determination of galaxy redshift distributions is possibly the largest source of systematics. 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 mitigate the effect of this systematic. 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-SPS) 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 a Stage-III setup and that the future inclusion of constraining spectroscopic data in the modelling will lead to redshift distribution estimates that will enable cosmological and galaxy population studies with the precision required by Stage IV experiments.

Talk in presence and via Zoom:

https://uni-hamburg.zoom.us/j/66006535328?pwd=aGkrSjJIYmZjK0VpYlpGL0ZrdHg2UT09