Multi-wavelength study of diffuse radio objects in the galaxy clusters

Abstract

According to the standard cosmology, the Universe started with the Big Bang around 13.7 billion years ago. At this stage, the Universe was a condensed mixture of elementary particles and photons at extremely high temperature, and as it started to expand and cooled, neutral hydrogen started to form and photons decoupled from the baryons. Since then it went through different phases of evolution to finally form the structures we see today. The study of these different stages of cosmic evolution has opened up multiple area of active research along with the development of right instrument to probe these epochs. The aim of this thesis is to study the most recent phase of the cosmic evolution where large scale structures like galaxy clusters and filaments are formed, giving rise to the cosmic web. On larger scales, cluster samples are handy tools to understand the formation and evolution of large scale structures by studying the average statistical properties of clusters as a function of redshift. As clusters are relatively luminous at many wavelengths, they can be easily traced to very high redshifts and can be a very important observational tool for cosmologists, in particular, to constrain cosmological parameters. This thesis aims to understand the physical mechanisms governing the astrophysical phenomena in the cluster ICM. In particular, the formation mechanisms of diffuse radio sources found in the ICM, i.e., radio halos, relics, minihalos and phoenixes.