Colloquium on Nov. 19, 2020

The impact of baryon-CDM perturbations on halo baryon fraction and clustering

Speaker:Titouan Lazeyras (SISSA)

Venue:Video Conference

Time:16:00 PM, Thursday, Nov. 19, 2020

Abstract:

Baryons and cold dark matter did not comove prior to recombination, leading to so-called baryon-CDM isocurvature perturbations. These perturbations are usually neglected in the analysis of Large-Scale Structure data since they are washed out at low redshift by gravitational evolution. However taking them into account might become important in the era of high precision cosmology. I will present recent results of gravity-only 2-fluid simulations to assess the impact of such perturbations on dark matter halos baryon fraction and clustering. The effect on clustering measured via the cross-power spectrum between the halo field and relative baryon-CDM density one, as well as the associated bias parameter. Finally I will show that in certain cases the impact of such perturbations on the halo-halo power spectrum can be non-negligible and degenerate with the one of massive neutrinos.

Report PPT:SWIFAR_Titouan Lazeyras.pdf