The infrared luminosity function of galaxies in the Coma Cluster

An infrared survey of the central 650 arcmin(2) of the Coma Cluster is used to determine the H-band luminosity function for the cluster. Redshifts are available for all galaxies in the survey with H < 14.5, and for this sample we obtain a good fit to a Schechter function with H* = 11.13 and alpha = -0.78. These luminosity function parameters ale similar to those measured for field galaxies in the infrared, which is surprising considering the very different environmental densities and, presumably, merger histories for field galaxies. For fainter galaxies, we use two independent techniques to correct for field galaxy contamination in the cluster population: the B - R color-magnitude relation and an estimate for the level of background and foreground contamination from the literature. Using either method, we find a steep upturn for galaxies with 14 < H < 16, with slope alpha similar or equal to -1.7.