Near-Infrared Survey of the GOODS-North Field: Search for Luminous
  Galaxy Candidates at z=>6.5
  We present near-infrared (NIR; J & Ks) survey of the Great Observatories
Origins Deep Survey-North (GOODS-N) field. The publicly available imaging data
were obtained using the MOIRCS instrument on the 8.2m Subaru and the WIRCam
instrument on the 3.6m Canada-France-Hawaii Telescope (CFHT). These
observations fulfill a serious wavelength gap in the GOODS-N data - i.e., lack
of deep NIR observations. We combine the Subaru/MOIRCS and CFHT/WIRCam archival
data to generate deep J and Ks band images, covering the full GOODS-N field
(~169 sq. arcmin) to an AB magnitude limit of ~25 mag (3sigma). We applied
z'-band dropout color selection criteria, using the NIR data generated here. We
have identified two possible Lyman Break Galaxy (LBG) candidates at z\gtrsim6.5
with J\lesssim24.5. The first candidate is a likely LBG at z\sim6.5 based on a
weak spectral feature tentatively identified as Lyalpha line in the deep
Keck/DEIMOS spectrum, while the second candidate is a possible LBG at z\sim7
based on its photometric redshift. These z'-dropout objects, if confirmed, are
among the brightest such candidates found so far. At z\gtrsim6.5, their star
formation rate is estimated as 100-200 solar mass per year. If they continue to
form stars at this rate, they assemble a stellar mass of ~5x10^10 solar mass
after about 400 million years, becoming the progenitors of massive galaxies
observed at z\sim5. We study the implication of the z'-band dropout candidates
discovered here, in constraining the bright-end of the luminosity function and
understanding the nature of high redshift galaxies.
