Optical - Near-Infrared catalogue for the AKARI North Ecliptic Pole Deep
  Field
  Aims. We present an 8-band (u*, g', r', i', z', Y, J, Ks) optical to NIR deep
photometric catalog based on the observations made with MegaCam and WIRCam at
CFHT, and compute photometric redshifts, zp in the North Ecliptic Pole (NEP)
region. Our catalog provides us to identify the counterparts, and zp for AKARI
NIR/MIR sources.
  Results. The estimated 4sigma detection limits within an 1" aperture radius
are 26.7, 25.9, 25.1, and 24.1 mag [AB] for g', r', i', and z'-bands and 23.4,
23.0, and 22.7 mag for Y, J, and Ks-bands, respectively. There are a total of
85797 sources in the band-merged catalog. An astrometric accuracy of this
catalog determined by examining coordinate offsets with regard to 2MASS is
0.013" with a root mean square offset of 0.32". We distinguish 5441 secure
stars from extended sources using u*-J vs. g'-Ks colors, combined with the
SExtractor stellarity index of the images. Comparing with galaxy spectroscopic
redshifts, we find a photometric redshift dispersion, sigma_(dz/(1+z)), of
0.032 and catastrophic failure rate, dz/(1+z)>0.15, of 5.8% at z<1, while a
dispersion of 0.117 and a catastrophic failures rate of 16.6% at z>1. We extend
estimate of the zp uncertainty over the full magnitude/redshift space with a
redshift probability distribution function and find that our redshift are
highly accurate with z'<22 at zp<2.5 and for fainter sources with z'<24 at z<1.
From the investigation of photometric properties of AKARI infrared sources
(23354 sources) using the g'z'Ks diagram, <5% of AKARI sources with optical
counterparts are classified as high-z (1.4<z<2.5) star-forming galaxies. Among
the high-z star-forming galaxies, AKARI MIR detected sources seem to be
affected by stronger dust extinction compared with sources with non-detections
in the AKARI MIR bands. The full, electronic version of our catalog with zp
will be available at the CDS.
