Cosmology Seminar: Teppi Okumura, IPMU, “Theoretical modelling of redshift-space distortions for galaxies toward precision cosmology”

Event time: 
Friday, December 16, 2016 - 3:00pm to 4:00pm
46 Hillhouse (), 207 See map
46 Hillhouse
New Haven, CT 06511
Event description: 

Revealing the acceleration of the cosmic expansion is one of the most important issues in cosmology. The mysterious dark energy could be driving the acceleration, or gravity law predicted from Einstein’s theory of general relativity could be breaking down at cosmological scales. To investigate the origin of the acceleration, observations of large-scale structure of the Universe traced by galaxy surveys are considered as the best probe through a measurement of baryon acoustic oscillations (BAO) and redshift-space distortions (RSD). In this talk, I will first demonstrate that the accuracy of the current theoretical models for extracting the dark energy or gravity properties is not high enough for the future precision surveys such as the DESI and Subaru PFS surveys. Particularly, incorrect modeling of redshift-space distortions of satellite galaxies easily leads to a wrong constraint on gravity theories. I will present two complementary approaches which overcome this problem. One is to predict the galaxy power spectrum by combining cosmological perturbation theory and halo model. Another is to reconstruct the power spectrum of dark matter halos from the observed galaxy distribution.