(Proposal ID) S12A-096

(PI) Silverman, John

(Proposal Title)
Subaru/FMOS survey of star formation at z~1.5 in COSMOS

(Abstract)
Large spectroscopic surveys of high-redshift galaxies have been conducted 
primarily in the optical, thus introducing a strong selection bias against 
massive, star-forming galaxies which tend to be dust obscured, especially at 
rest-frame UV.  To remove such an impediment, we propose to exploit the unique 
capabilities of FMOS to acquire near-infrared spectroscopy of 3500 star-
forming galaxies in the COSMOS field at an epoch (1.2 < z < 1.7) of rapid 
galaxy formation.  The detection of H alpha in emission will enable us to 
(1) obtain accurate redshifts, (2) measure star formation rates less impacted 
by dust extinction, and (3) map the distribution of large-scale structures at 
these redshifts.  Our program will determine how star formation depends on 
stellar mass and environment, both recently recognized as drivers of galaxy 
evolution at lower redshifts.  In conjunction with large optical spectroscopic 
surveys in COSMOS, empirical models of galaxy evolution can be effectively 
expanded to cover a wide dynamic range in redshift (0<~ z <~3.5).  
Furthermore, these spectra will provide an invaluable resource for future HSC 
surveys and ALMA followup of COSMOS.