The bright galaxy population of five medium redshift clusters - II. Quantitative galaxy morphology

摘要

Aims. Following the study presented in our previous paper, basedon the Nordic Optical Telescope (NOT) sample, which consists of fiveclusters of galaxies within the redshift range imaged in the central 0.5-2Mpc in very good seeing conditions, wehave studied the quantitative morphology of their bright galaxypopulation Methods. We analyzed the surface brightness profiles of thegalaxy population in those clusters, after performing simulations inorder to check the reliability of the fits. We also derived aquantitative morphological classification. Results. The structural parameters derived from these analysesare presented. We obtained that the structural parameters of E/S0galaxies are similar to those shown by galaxies in low redshiftclusters. However, the disc scales are different. In particular, thescales of the discs of galaxies in medium redshift clusters arestatistically different than those located in similar galaxies in theComa cluster. However, the scales of the discs of galaxies in mediumredshift clusters are similar to nearby field galaxies. Conclusions. Our results suggest that the evolution of the disccomponent of galaxies in clusters is faster than in field ones.Mechanisms like galaxy harassment showing timescales of 1Gyrcould be responsible for this disc scale evolution. This indicates thatspiral galaxies in clusters have undergone a strong evolution in thelast 2.5 Gyr or that Coma is in some way anomalous. Key words: galaxies: clusters: general - galaxies: structure - cosmology: observations