The Hawaii-AAO K-band Galaxy Redshift Survey -- Paper I: The Local K-band Luminosity Function

Abstract

We present the K-band local luminosity function derived froma sample of 1056 bright (K<15) K-selected galaxies from the Hawaii-AAO K-band redshift survey. The Hawaii-AAO K-band redshift survey covers 4 equatorial fields with a total area of 8.22 $°^2$. We derive both the non-parametric and Schechter luminosity function from our data, and determine $M^*(K)=-23.70\pm0.08+5\log_{10}(h)$, $α=-1.37\pm0.10$ and $ϕ^*=0.013\pm0.003 h^3 \Mpc^{-3}$ for a universe with $Ω_m=0.3$ and $Ω_Λ=0.7$. We also measure the K-band luminosity function for the early- and later-type galaxies from our morphologically classified subsample. It appears that later-type galaxies have a fainter $M^*$ and a steep slope, while early-type galaxies have a much brighter $M^*$ and a quite flat slope in their K-band luminosity functions. This is consistent with what have been found in optical type dependent luminosity function. The K-band luminosity density derived using our luminosity function is now measured at a similar redshift depth to optical luminosity densities in the SDSS redshift survey. It is 2 times higher than the previous measurement from the shallower 2MASS sample and resolves the previously reported discrepancies between optical and near-IR luminosity densities.