Luminosity Function of Cluster Galaxies

Abstract

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 (H 0 = 50 km/s/Mpc).

The Luminosity Function of cluster galaxies. III.

“…The choice is the most reasonable one following the work by Sandage et al (1985) on the Virgo cluster; it is evident from the data of the present analysis, Figs. 1 and 2 and as indicated also in Molinari et al (1998) and references therein. In a cluster, as it is very evident also from our data, the bright galaxies are located in the central region and these are the galaxies that are fitted by the Gaussian component of the LF.…”

“…The detailed description of the observations, the data analysis and the algorithms we used can be found in the papers by Molinari et al (1998), Moretti et al (1999), and the laurea thesis by Moretti (1997), Ratti (1998), andParolin (2002). As we want to present the results from the analysis of 7 clusters of the original sample, we give here just few informations to ease the reading (see Table 1).…”

Deep near-IR observations of the Chandra Deep Field and of the HDF South

“…Evidence of a steep LF of field galaxies at infrared wavelength come from Szokoly et al (1998) who find a slope α = −1.3 and from Bershady et al (1999) who estimate α = −1.6. Other evidence in favor of α −1 come from the results obtained on optically selected samples of field galaxies (Marzke et al 1994(Marzke et al , 1997Zucca et al 1997) and of cluster galaxies (De Propris et al 1998;Lobo et al 1997;Bernstein et al 1995;Molinari et al 1998). However, such a steep LF, which contributes substantially to the galaxy counts at optical wavelengths (see e.g.…”

Environmental effects on the galaxy luminosity function in the cluster of galaxies Abell 496

“…The CFH12K camera is made of 12 2K×4K CCDs (hereafter, we will label the various CCDs from A to L anticlockwise from the south east corner). A global sketch of our field, together with those previously observed by Molinari et al (1998) and by our team are shown in Fig. 1, superimposed on the positions of the galaxies with redshifts belonging to the cluster (see the Durret et al (1999b) catalogue).…”

“…Positions of all the galaxies (relatively to the cD) with redshifts in Abell 496 from the Durret et al (1999b) catalogue (crosses). The large rectangle shows the size of the present image; the small squares forming a sort of cross in the center correspond to the CCD catalogue by Slezak et al (1999); the squares drawn with dotted lines indicate the fields covered by Molinari et al (1998).…”