Session 3 - Evolution of Galaxies & Clusters of Galaxies.
Display session, Monday, June 09
South Main Hall,

## [3.04] The Near Infrared Luminosity Function of Galaxies in the Coma Cluster

P. Eisenhardt, R. De Propris (JPL/Caltech)

Optical and near infrared photometry from the U through K bands has been measured for galaxies with H < 16 in a 22' \times 29' field in the core of the Coma cluster. Cluster members are selected via their redshifts at H < 13 and by the color magnitude relation for fainter galaxies.

The H luminosity function is well fit by a Schechter function with H= 10.81 \pm 0.35 and \alpha = -0.91 0.11 for H < 14.5. This agrees well with the field near infrared luminosity function determined by Gardner et al. (1997). There is evidence for a significant upturn in the slope for 14.5 < H < 16.

Galaxies obey a tight color-magnitude relation: the slope of the relation is steeper for bluer colors than for redder ones. Elliptical galaxies have shallower slopes than do S0 galaxies. We also discuss the dispersion about these relations.

Internal color gradients for ellipticals are \sim -0.14 mag per decade in radius in U-V and indistinmguishable from 0 in V-I, consistent with previous results. We detect no gradient in the average color of galaxies as a function of distance from the cluster center, within the surveyed field.