New detections and statistics of diffuse radio sources in galaxy clusters

Abstract

Galaxy clusters are the largest gravitationally bound structures of the Universe, formed from density fluctuations and grown hierarchically through the extreme process of merging and mass accretion. They represent very interesting tools to study the cosmology and the evolution of large scale structures. Synchrotron non-thermal emission detected in the forms of radio halos, relics and minihalos according to their morphology, size and location is linked to the different dynamical state of the hosting clusters. Halos and relics are detected in clusters characterized by a strong merger activity and a dynamical disturbed state, while minihalos are present only in relaxed cool-core clusters. In spite of many encouraging results obtained up to now, the occurrence and the luminosity function of diffuse radio sources with the redshift are still unknown: present data are strongly limited to nearby clusters (z < 0.2 − 0.3). The aim of this PhD thesis is mainly to investigate the evolutionary history of non-thermal properties of galaxy clusters and to determine whether the correlations observed at low redshift evolve with time. To attempt this ambitious goal we selected an homogeneous sample of 44 massive and high X-ray luminous galaxy clusters in the redshift range 0.3 ≤ z < 0.7, extracted from the Ebeling MAssive Cluster Survey (MACS). We have undertaken an observational campaign on this sample with the JVLA in L-band, C and D configurations.