A COMPLETE GALAXY REDSHIFT SURVEY .5. INFRARED LUMINOSITY FUNCTIONS FOR FIELD GALAXIES

A subsample of the optically selected Anglo-Australian Redshift Survey, which we have observed at infrared wavelengths, is used to construct the first infrared luminosity function for 'field' galaxies. Infrared completeness limits for the survey are estimated using a V/V(max) test in order to obtain a sample complete in the K (2.2 mum) passband, from which luminosity function parameters are derived using standard techniques. A new statistical method is then developed to construct the infrared luminosity function from the full optically selected survey, and possible sources of bias in this technique are examined. The best estimates of the infrared Schechter luminosity function parameters are M(K)* = - 25.1 +/- 0.3 and alpha = -1.0 +/- 0.3 for H-0 = 50 km s-1 Mpc-1. We find that E/S0 and spiral galaxies have identical infrared luminosity functions to within the errors. This is interpreted in terms of a similar formation and evolutionary history for E/S0s and spiral bulges. The infrared luminosity functions are then used to predict number-magnitude counts at 2.2 mum. The best agreement between the observed and predicted counts is obtained for no-evolution models with q0 approximately 0.02 and a normalization of phi* = (0.1 4 +/- 0.02) x 10(-2) (H-0/50)3 Mpc-3.