Speaker:	Tomomi Sunayama (University of Arizona)
Title:	TBAAn accurate cluster cosmology analysis using SDSS and HSC Y3 data
Date (JST):	Tue, Dec 12, 2023, 12:00 - 12:30
Place:	Seminar Room A
Abstract:	Galaxy clusters are the most massive gravitationally self-bound objects in the Universe. These clusters form at the rare high peaks of the primordial density fluctuations, and they subsequently trace the growth of structure in the Universe as they grow in mass and abundance. As such, clusters constitute a natural cosmological probe for constraining the properties of the primordial fluctuations as well as cosmological parameters including the nature of dark energy. Clusters are, however, also known to be susceptible to many systematics such as selection biases and systematics. Furthermore, the recent cosmology result from DES using photometrically-identified clusters, which favored lower Omega_m and higher sigma8 compared against other constraints from CMB and large-scale structure, question optical clusters as a cosmological probe. We developed a novel analysis method that fully forward models the abundances, weak lensing, and clustering of galaxy clusters including an accurate modeling of systematics such as projection effects. Projection effects are the misidentification of interloper galaxies as a member of clusters and are considered the biggest systematics. We found that projection effects not only alter mass-observable relation but also boost the amplitude of clustering and lensing signals due to the anisotropic distribution of optical clusters and modeling projection effects is a key to an accurate cosmological analysis using optical clusters. In this talk, I will present the result of a joint analysis using Sloan Digital Sky Survey (SDSS) redMaPPer clusters and Hyper-Suprime Cam (HSC)-Y3 shape catalog.

← Back