Protocluster Region Research Articles

Subaru Deep Near-Infrared Imaging of the Field of a Possible Proto-Cluster Near the Radio Galaxy 53W002 at $z=2.4$

Abstract We present the results of deep $K^\prime$ - and $J$-band imaging of the field of a proto-cluster region near the radio galaxy 53W002 at $z=2.390$ with the Subaru Telescope. The data were analyzed together with deep optical and near-infrared (NIR) images taken with the Hubble Space Telescope to investigate the properties of ten optically compact emission-line galaxies and candidates. Excluding the three objects which may contain active galactic nuclei, many are faint or undetected at $K^\prime$ ($\lambda_\mathrm{rest} \approx 6000 \,{Å}$), and are therefore revealed to be intrinsically small starbursting objects. On the other hand, we detect few objects with colors and magnitudes expected for quiescent massive galaxies at $z=2.4$ in the field.