Subaru/MOIRCS near-infrared imaging in the proto-cluster region at z = 3.1

Abstract

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 arcmin2 field to depths of J = 24.5, H = 24.3, and K = 23.9 (5σ). We examined the distribution of the K-selected galaxies at z ∼ 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 Lya blobs (LABs). We investigated the correlation between the K-selected objects and the LABs, and found that several galaxies with stellar mass, M* = 109-1011M⊙, 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 K8-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 Lyα emission may be closely correlated with their previous star-formation phenomena. © 2008. Astronomical Society of Japan.