SSA 22 field NIR imaging

Using a narrow-band filter centered at 2.033{mu}m, [O III] {lambda}5007 emitters at z~3.06+/-0.02 were searched to examine star-forming activities in an over-density region where a clustering of Lyman Break Galaxies (LBGs) and Lyman {alpha} emitter candidates around z=3.09 was reported, though the targeted redshift is slightly different from that of the peak of the over-density region.

Although one emitter candidate at z=3.06 was detected, it is likely to be located at a redshift of between 1 and 2 judged based on multi-band photometry. Another emission-line object was detected in another narrow-band filter (``off band'' filter) centered at 2.120{mu}m, which is identified with a galaxy at z=0.132 (the emission line is Paschen {alpha}). The K'-band imaging data revealed the presence of 12 Extremely Red Objects (EROs) with I_814_-K'>=4.