Journal Club

Weak lensing analysis of CODEX clusters using Dark Energy Camera Legacy Survey

by Dr Anirut Phriksee (Post-Doc)

Asia/Bangkok
Cassiopeia (Narit)

Cassiopeia

Narit

Description

Galaxy clusters are the massive gravitationally bound structures in the universe. Studying this class of objects provides important information on the formation and evolution of large-scale structures and on the dark matter distribution. Weak gravitational lensing, a phenomenon related to the deflection of light by a massive object like a galaxy cluster can be used to estimate the mass distribution in galaxy clusters. In this talk, I present the weak lensing analysis of 279 galaxy clusters from the COnstrain Dark Energy with X-ray survey (CODEX), using imaging data from 4200 square degrees of the DECam Legacy Survey (DECaLS) Data Release 3. The cluster sample results from a joint selection in X-ray, optical richness in the range 20 ≤ λ < 110, and redshift in the range 0.1 ≤ z ≤ 0.2. I model the cluster mass (M200c) and the richness relation⁠. By measuring the CODEX cluster sample as an individual cluster, I obtain the best-fitting values and the richness scaling index, consistent with a power-law relation. Moreover, I separate the cluster sample into three richness groups; λ = 20–30, 30–50, and 50–110, and measure the stacked excess surface mass density profile in each group. The results show that both methods are consistent. In addition, I find a good agreement between the weak lensing-based scaling relation and the relation obtained with dynamical masses estimated from cluster member velocity dispersions measured by the SDSS-IV/SPIDERS team. This suggests that the cluster dynamical equilibrium assumption involved in the dynamical mass estimates is statistically robust for a large sample of clusters.