(Proposal ID) S12B-008

(PI) Kodama, Tadayuki

(Proposal Title)
Scrutinizing biased galaxy formation with panoramic near-infrared spectroscopy

(Abstract)
We have nearly completed the imaging part of the Mahalo-Subaru project in 
which we have mapped out star-forming activities over the wide range in 
redshift (1.5--2.5) and in environment. Our unique sample of clusters and a 
blank field and the narrow-band (NB) emitters therein will serve as excellent 
laboratories to investigate the environment-dependent galaxy formation. We now 
propose to conduct an intensive near-infrared (NIR) spectroscopic survey by 
taking the advantage of Subaru's two unique wide-field NIR spectrographs, FMOS 
and MOIRCS. We will target ~1200 line emitters in 6 clusters and a blank field,
 and detect a series of major nebular emission lines in order to fully 
characterize the properties of the NB emitters. Specifically, we will derive 
(1) membership of emitters to confirm structures, and velocity dispersion of 
each clump as a proxy of its system mass, (2) true star formation rates 
reliably corrected for dust extinction, (3) gaseous metallicities to 
characterize evolutionary states, and (4) AGN contribution to investigate 
co-activation with SF activity, and compare these quantities in detail as a 
function of redshift and environment to physically understand the biased 
galaxy formation at high-z and the rapid decline of star forming activities 
with time in dense environments.