Subaru/MOIRCS Near-Infrared Imaging in the Proto-Cluster Region at z=3.1

We present the results of deep near-infrared imaging observations of the z = 3.1 proto-cluster region in the SSA 22a field taken by MOIRCS mounted on the Subaru Telescope. We observed a 21.7 arcmin(2) field to depths of J = 24.5, H = 24.3, and K = 23.9 (5 sigma). We examined the distribution of the K-selected galaxies at z similar to 3 by using a simple color cut for distant red galaxies (DRGs) as well as a photometric-redshift selection technique. The marginal density excess of DRGs and the photo-z selected objects were found around the two most luminous Ly alpha blobs (LABS). We investigated the correlation between the K-selected objects and the LABS, and found that several galaxies with stellar mass, M-* = 10(9)-10(11) M-circle dot, exist in the vicinity of LABS, especially around the two most luminous ones. We also found that 7 of the 8 LABS in the field have plausible K-s-band counterparts, and the sum of the stellar mass possibly associated with LABS correlates with their luminosity and surface brightness, which implies that the origin of Ly alpha emission may be closely correlated with their previous star-formation phenomena.