Open group seminar:  Shivam Pandey (UPenn)

2:30–3:30 pm ERC 401

Shivam Pandey (UPenn) "Perturbation theory for non-linear galaxy biasing in photometric galaxy surveys"

Small scale correlations between the tracers of large-scale structure carry the majority of the information but are challenging to model due to complex astrophysics and the relationship between galaxies and the underlying matter distribution, i.e., galaxy biasing. I will describe hybrid perturbation theory (PT) models of non-linear galaxy bias for applications to photometric galaxy surveys, focusing on recent results from the Dark Energy Survey (DES). I will describe its percent level validation using various mock catalogs. I will then show the cosmological constraints obtained from applying these models on the DES Year-3 (DES Y3) galaxy clustering and weak gravitational lensing measurements. We find that analyzing smaller scales with a non-linear bias model leads to 20-40% tighter cosmological constraints compared to a linear bias model analyzing larger scales. I will also briefly describe a color-dependent hotometric issue impacting the DES Y3 results and how we minimize its impact on our results by changing the selection criteria of red galaxies.

Event Type


Dec 9