Tracing of the chemical evolution of the massive elliptical galaxy NGC 3377 using a merger scenario

摘要

Mergers are thought to play a significant role in the formation of galaxies in clusters. The chemical evolution of the halo of the massive elliptical galaxy NGC 3377, a member of the Leo cluster, is considered in the framework of such a merger scenario. An open chemical evolution model is set up to calculate the metallicity distributions of pre-merging fragments. The model assumes that pristine gas was accreted onto the fragments during their whole evolution before their merger. The metallicity distribution resulting from the overlay of a variable number of fragments is then compared to observational data for NGC 3377. It was found that the observed metallicity distribution function of this elliptical galaxy is reproduced by merging at least five fragments from two different groups, namely low-and high-metallicity fragments.