The 60-  and far-infrared luminosity functions of IRAS galaxies

The 60-μm luminosity function for galaxies detected by IRAS is determined from a compilation of samples with highly complete redshift information totalling 2818 galaxies, including the new QMC–Cambridge–Durham survey and samples including many nearby, low-luminosity galaxies. We use clustering-independent maximum likelihood methods throughout. A non-parametric estimator is used to determine the shape of the luminosity function, and the best parameter set found for a suitable analytic form. We find the luminosity function to be well described by a Gaussian dependence on log(luminosity), changing over to a very flat power law at low luminosities: this latter feature is in strong contrast to previous results. We find our results to be very insensitive to various models for deviations from the Hubble flow and to different values of the Hubble constant.