(Proposal ID) S16A-027

(PI) Kajisawa, Masaru

(Proposal Title)
Spectroscopic Follow-up  for Massive Galaxies in a z=2.39 Proto-cluster II

(Abstract)
{This is a continuation program from S15A-023, where only 1 night out of 3 
requested nights was allocated and observed.} A proto-cluster around a radio 
galaxy 53W002 at z=2.39 was discovered as a density excess of Lyalpha Emitters 
(LAEs). Recently we found a large-scale high-density structure of LAEs at ~3 
arcmin north of 53W002. We then searched NIR-selected massive galaxies at the 
same redshift in this region and found that the color-selected massive galaxy 
candidates are preferentially located along the high-density structure of LAEs 
on ~5 Mpc scale. We here propose a NIR follow-up spectroscopy of the massive 
galaxy candidates at z~2.4 in order 1) to confirm whether these massive galaxy 
candidates belong to the high-density structure of LAEs or not, 2) to estimate 
the physical properties, especially, average stellar age in order to constrain 
the evolutionary phase of these massive cluster members. We also compare 
spatial distribution between these massive galaxies and LAEs in order to study 
the relationship between the formation and evolution of these massive and less 
massive populations. The proposed observations enable us to investigate how 
galaxies formed and evolved in the high-density structure which is expected to 
become a typical cluster at the present universe.