Sergio Contreras (DIPC)
Tue. September 14th, 2021, 11:30 am-12:30 pm
How well does galaxy clustering constrain cosmology?
On the LCDM cosmology, dark matter collapses into virialise objects called haloes. The abundance and distribution of these haloes are a direct consequence of the cosmology of the Universe. By constraining the dark matter halo clustering, we could also constraint the cosmology from our Universe. Since dark matter haloes can not be observed, we need to use galaxies to trace them.
In this talk, I will present a new method that we develop capable of constraining cosmological information from the redshift space galaxy clustering. We use the scaling of cosmological simulations and the SubHalo Abundance Matching extended (SHAMe) empirical model to produce realistic galaxy clustering measurements over a wide range of cosmologies. We generate more than 100,000 clustering measurements at different cosmological and SHAMe parameters to build an emulator capable of reproducing the projected correlation function, monopole and quadrupole of the galaxies. We run an MCMC using this emulator to constrain the cosmology of the TNG300 hydrodynamic simulation. We correctly predicted the cosmology of the TNG300 simulation constraining sigma8 between [0.75,0.83] and Omega matter h^2 between [0.127,0.162]. The best constraints are obtained when including scales below 2 Mpc/h and when combining all different clustering statistics. We conclude that our approach can be used to constrain cosmological and galaxy formation parameters from the galaxy clustering of galaxy surveys.
Host: Idit Zehavi