O EFEITO AMBIENTAL NO AGLOMERADO DE GALÁXIAS RX J0152.3-1357, EM Z = 0.84

Abstract

Environmental effects in cluster RX J0152.7-1357, at z = 0.84 External mechanisms can transform galaxies over time. This occurs predominantly in denser environments such as groups and clusters of galaxies, where the gravitational interactions and the gas supply are more complex compared to isolated galaxies. In order to study these transformations in clusters, we are performing a study of the relatively young and complex high redshift cluster RX J0152.7-1357 at z = 0.84. Our data consists of wide-field images in the rest-frame far- and near-UV from GALEX and VLT/VIMOS, optical photometry from Subaru, and detailed morphological information from the Hubble Space Telescope for over a hundred spectroscopically confirmed cluster members. By analyzing the trends in properties of galaxies, such as star formation rate, stellar mass, age, spectral type and morphology as a function of the cluster-centric radius, local density, and location relative to different spatial and kinematic substructures in and around the cluster, we can constrain various scenarios for galaxy transformations and the cluster-building process. We conclude that the gravitational interactions in a cluster of galaxies at z = 0.84 already make evident the morphology-density relation and the appearance of the red sequence. Infalling galaxies located in the outskirts and in intermediate density environments already show signs of star formation quenching. The galaxies undergo an accelerated transformation from active to passive when they enter the central region of the cluster.