(Proposal ID) S17A-133

(PI) Onodera, Masato

(Proposal Title)
Near-IR emission lines: understanding dusty galaxies evolution  to z=1

(Abstract)
We ask for 2  Subaru/MOIRCS nights to obtain H&K spectroscopy of 100 Herschel-
selected, ultraluminous, dusty star forming galaxies  to detect their rest-
frame near-IR nebular lines Pa beta, [SIII], HeI and FeII up to z~1. Suffering 
much less from dust attenuation, these lines provide a unique access to the 
densest and most  obscured cores of starbursting galaxies, totally unreachable 
using rest-frame optical lines traditionally observed (Balmer series, [OII], 
[OIII], [NII]). We will use near-IR line ratios for a pilot exploration of the 
gas metallicity (i.e., S is an alpha element, thus [SIII]/Pa beta is a 
potential O/H metallicity tracer, FeII is a product of Type I supernovae 
explosions and shock/AGN tracer), exploring correlations with unbiased tracers 
of total SFR (Pa beta, infrared luminosity) and stellar mass. This will 
potentially provide a first assessment of the issue of the metal content of 
starburst galaxies and new clues on their black hole growth with obvious 
implications on the understanding of the importance of starbursting phases in 
galaxy evolution. Moreover, we will provide useful empirical correlations and 
calibrations comparing observations with CLOUDY photoionization modeling, 
paving the way for forthcoming routine JWST observations of these lines all 
the way to z>10.