(Proposal ID) S14A-019

(PI) Koyama Yusei

(Proposal Title)
 GANBA-Subaru: dissecting distant star forming galaxies across environments

(Abstract)
Studying the internal physics of distant galaxies is a rapidly-developing 
frontier in the extragalactic astronomy. However, all the previous studies 
have been focusing on field galaxies. We here propose to carry out an 
AO-assisted, narrowband (NB2315; lambdac=2.315 mum) imaging observation of a 
newly discovered rich proto-cluster at z = 2.53 (USS1558-003). The proto-
cluster was discovered as a strong over-density of Halpha emitters by our 
(seeing-limited) NB observations with MOIRCS. We now propose to spatially 
resolve the strong Halpha line emissions of individual galaxies to ~1 kpc 
by the AO-assisted imaging with our companion (identical) NB filter on IRCS. 
Our goal is to map and resolve the internal distribution of SF activity in 
those young cluster galaxies and to identify the physical processes that 
trigger/truncate star formation in those systems. Any environmental effects 
must have left some footprints in their internal structures, and such 
environment-dependent signatures will be directly identified by comparing with 
the field galaxies. We will also combine this unique data-set with our 
approved HST images, providing us with size, morphology (clumps), stellar 
mass and extinction maps to further characterize the physical states of these 
progenitors of cluster early-type galaxies.