(Proposal ID) S14B-158

(PI) Toshikawa Jun

(Proposal Title)
 Searching for Protoclusters across Cosmic Time

(Abstract)
Revealing the large-scale structure formation and galaxy evolution in high 
dense environment has been one of the biggest issues. To approach this, 
protoclusters will provide a great deal of information on the primordial 
conditions of galaxy clusters. In our previous study, we have discovered a 
protocluster at z=6.01 by using the combination of i-dropout technique and 
wide-field imaging capability of SprimeCam. Following this discovery, we 
propose to take FOCAS spectroscopy for other plausible protocluster candidates 
at z~3-6 which are discovered in the ~4deg^2 blank field of CFHTLS Deep Fields 
with more than 4sigma overdense significance at peak. First of all, we would 
like to definitely confirm that our target regions are real protoclusters. 
Then, we can qualitatively characterize the general properties of early 
structures and its possible environmental effects. The comparison of internal 
structure of protoclusters with those of low redshift and local cluster will 
trace cluster formation in a virialization process. The proposed systematic 
observation excellently complements the previous researches and must provide 
us with diverse viewpoints on protoclusters. From this study, we will be able 
to approach nature of cluster formation and galaxy evolution in high dense 
environment across cosmic time.