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J- and Ks-band Galaxy Counts and Color Distributions in the AKARI North Ecliptic Pole Field

Koji Imai·Hideo Matsuhara·Shinki Oyabu·Takehiko Wada·Toshinobu Takagi·Naofumi Fujishiro·Hitoshi Hanami·Chris P. Pearson
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Abstract

We present the J- and Ks-band galaxy counts and galaxy colors covering 750 square arcminutes in the deep AKARI North Ecliptic Pole (NEP) field, using the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer (FLAMINGOS) on the Kitt Peak National Observatory (KPNO) 2.1m telescope. The limiting magnitudes with a signal-to-noise ratio of three in the deepest regions are 21.85 and 20.15 in the J- and Ks-bands respectively in the Vega magnitude system. The J- and Ks-band galaxy counts in the AKARI NEP field are broadly in good agreement with those of other results in the literature, however we find some indication of a change in the galaxy number count slope at J~19.5 and over the magnitude range 18.0 < Ks < 19.5. We interpret this feature as a change in the dominant population at these magnitudes because we also find an associated change in the B - Ks color distribution at these magnitudes where the number of blue samples in the magnitude range 18.5 < Ks < 19.5 is significantly larger than that of Ks < 17.5.

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Koji Imai, Hideo Matsuhara, Shinki Oyabu, Takehiko Wada, Toshinobu Takagi, Naofumi Fujishiro, Hitoshi Hanami, Chris P. Pearson. 2007-02-09. J- and Ks-band Galaxy Counts and Color Distributions in the AKARI North Ecliptic Pole Field. https://doi.org/10.1086/513513

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