MULTICOLOR, 2-DIMENSIONAL PHOTOMETRIC-STUDY OF GALAXIES IN RICH ABELLCLUSTERS .1. OBSERVATIONS AND REDUCTIONS

We have embarked on a long term project to obtain high precision photo metry on individual galaxies in 45 rich clusters of galaxies. Data fro m the first set of six clusters have yielded BVRI photometric informat ion on 961 galaxies and 384 stars. These objects come from the central one Mpc of Abell 576, 957, 1185, 1377, 2063, and 2657, each of which is of richness class R greater than or equal to 1. Each object was exa mined with two radial surface brightness fitting functions, and an asy mptotic magnitude was determined. One fitting function produced a shap e parameter beta which, when taken in. combination with the color inde x (B-I), shows a breakdown of the three basic morphological types (E, S0, and S) into four beta types and a set of peculiar galaxies. Our re sults match previous studies well, and also provide some new insights into the clusters. In addition, we have examined the effects of plate scale on the determination of these photometric parameters. All parame ters were found to repeat across plate scale differences. We also exam ined the effects of co-adding frames in an attempt to understand the d egradation or improvement of the photometric parameters with increasin g signal-to-noise. (C) 1997 American Astronomical Society.