Astron. Astrophys. Suppl. Ser. 140, 155-170

The luminosity function of cluster galaxies

II. Data reduction procedures applied to the cluster Abell 496

A. Moretti ¹, E. Molinari ¹, G. Chincarini^1,2, and S. De Grandi¹

Send offprint request: moretti@merate.mi.astro.it

1 - Osservatorio Astronomico di Brera, Via Bianchi 46, I-22055 Merate, Italy
2 - Università degli Studi di Milano, via Celoria 16, I-20133 Milano, Italy

Received March 23; accepted August 30, 1999

Abstract:

We initiated a large project aimed to estimate the Luminosity Function of galaxies in clusters and to evaluate its relation to cluster morphology. With this paper we deem necessary to outline the general procedures of the data reduction and details of the data analysis. The cluster sample includes the brightest southern ROSAT all-sky survey clusters with z < 0.1. These have been observed in three colours g, r, i, and mapped up to a few core radii using a mosaic of CCD frames. E/S0 galaxies in the cluster core are singled out both by morphology (for the brightest galaxies), and by colour. The details of the data reduction procedure are illustrated via the analysis of the cluster Abell 496, which has been used as a pilot cluster for the whole program. The related photometric catalogue consists of 2355 objects. The limiting magnitudes (the reference Surface Brightness is given in parenthesis) in the various colours are respectively g(25.5) = 24.14, r(25.5) = 24.46, i(25.0) = 23.75. These correspond to the limiting absolute magnitudes -12.28, -11.96 and -12.67 (H₀ = 50 km/s/Mpc).

Key words: galaxies: photometry -- galaxies: cluster: general