(Proposal ID) S11A-070

(PI) Futamase, Toshifumi

(Proposal Title)
Weak Lensing Study of Statistical Property of DM Subhalos in Coma Cluster

(Abstract)
We propose to conduct weak lensing (WL) study of Coma cluster (z = 0.0236) 
with deep Suprime-Cam (S-Cam) imaging to probe the substructure of dark matter 
(DM) halos. As clearly demonstrated by our pilot WL study, the wide and high-
quality imaging capability of S-Cam will provides sufficient sensitivity and 
spatial resolution for detailed WL mapping of DM subhalos with M_sub>~10^12h^-1
M_sun inside the very close cluster, allowing us to examine, for the first 
time, the spatial distribution and the mass function of DM subhalos without 
any assumptions. We conduct WL substructure survey within r_200 within which 
the mean density is 200 times the critical mass density rho_cr, in order to 
obtain (1) the correlation between the spatial extent of subhalos and their 
projected distances from the cluster center, r_t(theta), and (2) the number 
density for subhalos dN_sub/d lnM_sub �� M_sub^-alpha, and (3) the subhalo 
mass function N(M_sub). These new observables provide the statistical property 
of DM subhalos which will not only easily distinguish between Cold Dark Matter
(CDM) and Warm Dark Matter(WDM), but also be used an unique cosmological test 
of CDM structure formation scenario on scales of <~a few Mpc, as well as 
important clues for understanding the history of hierarchical mass assembly on 
cluster mass scale.