Astro Lunch Seminar

Speaker: Ken Osato (Institut d'Astrophysique de Paris)
Title: Cosmology and cluster astrophysics with cross-correlations of HSC WL and Planck tSZ
Date (JST): Tue, Nov 26, 2019, 12:00 - 13:30
Place: Seminar Room A
Related File: 2465.pdf
Abstract: Galaxy clusters, which are the most massive bound objects in the Universe, are regarded as one of the most important cosmological probes because the abundance and clustering properties reflect the structure formation. On the other hand, the mass of galaxy clusters, which is the most fundamental quantity of galaxy clusters, is not the direct observable in X-ray or the thermal Sunyaev-Zel'dovich (tSZ) effect observations. In order to relate the observed flux to the mass, hydrostatic equilibrium, where thermal pressure balances the self-gravity of galaxy clusters, is widely adopted in practical analysis. However, mass calibration measurements suggest that 15-30% of the mass is supported by physical processes other than thermal pressure, which is called as non-thermal pressure. The precise evaluation of the non-thermal pressure is essential for mass estimate of galaxy clusters. In this work, we aim to scrutinize the non-thermal pressure support in galaxy clusters for the wide ranges of redshift and mass with weak gravitational lensing (WL) and tSZ. In addition to auto-correlations of tSZ, we employ the cross-correlation of tSZ and WL. In this talk, we present the analysis of the cross-correlation measurement with Subaru Hyper Suprime-Cam (HSC) for WL and Planck for tSZ to constrain cosmological parameters and hydrostatic bias parameters simultaneously. From the joint analysis of tSZ auto-power spectrum and tSZ-WL cross-correlation, we find non-thermal pressure supports 28.9% of the total mass of galaxy clusters. The estimated hydrostatic bias parameter is consistent with mass calibration measurements.