The K-Band Galaxy Luminosity Function
Abstract
We measured the K-band luminosity function using a complete sample of 4192 morphologically-typed 2MASS galaxies with 7 < K < 11.25 mag spread over 2.12 str. Early-type (T < -0.5) and late-type (T > -0.5) galaxies have similarly shaped luminosity functions, alphae=-0.92+/-0.10 and alphal=-0.87+/-0.09. The early-type galaxies are brighter, M*e=-23.53+/-0.06 mag compared to M*l=-22.980.06 mag, but less numerous, n*e=(0.0045+/-0.0006)h3/Mpc3 compared to n*l=(0.0101+/-0.0013)h3/Mpc3 for H0=100h km/s Mpc, such that the late-type galaxies slightly dominate the K-band luminosity density, jlate/jearly=1.17+/-0.12. Our morphological classifications are internally consistent, consistent with previous classifications and lead to luminosity functions unaffected by the estimated uncertainties in the classifications. These luminosity functions accurately predict the K-band number counts and redshift distributions for K < 18 mag, beyond which the results depend on galaxy evolution and merger histories.
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