The Morphological Type Dependence of K-band Luminosity Functions

Differential 2.2μm (K-band) luminosity functions are presented for a complete sample of 1570 nearby (Vgsr ≤ 3000 km/s, where Vgsr is the velocity measured with respect to the Galactic standard of rest), bright (K ≤ 10 mag), galaxies segregated by visible morphology. The K-band luminosity function for late-type spirals follows a power law that rises towards low luminosities whereas the K-band luminosity functions for ellipticals, lenticulars and bulge-dominated spirals are peaked with a fall off at both high and low luminosities. However, each morphological type (E, S0, S0/a-Sab, Sb-Sbc, Sc-Scd) contributes approximately equally to the overall K-band luminosity density in the local universe, and by inference, the stellar mass density as well.