(Proposal ID) S12B-051

(PI) Okoshi, Katsuya

(Proposal Title)
Survey for Galaxies associated with coincident, multiple HI gas at high redshift

(Abstract)
We propose to carry out a systematic search for reliable detections of star 
formation activity associated with coincident, multiple HI gas in spectra of 
gravitationally lensed quasars at high redshift with Keck telescope. By 
measuring the spatial distributions of HI gas and associated metals, we aim to 
establish a comprehensive picture for understanding how the circumgalactic 
media affect the formation and/or evolution of primordial galaxies. We are 
going to use the OSIRIS IFU spectroscopy mode whose sensitive wavelengths 
correspond to the redshifted H alpha/[OII] emission lines of host galaxies at 
z>2. The glare of background quasars often prevents from searching for the 
emission lines from host galaxies in the proximity ( < 1 arcsec) to HI 
absorbers. The high resolution imaging with LGS-AO enables us to approach very 
close to the HI gas at small impact parameter. The combination of high-
performance LGS-AO + IFU spectroscopy + gravitationally lensing is the most 
promising way to search for faint emissions associated with multiple HI gas 
from small to large impact parameters in the circumgalactic media.