Examination of Radio Halos and Corresponding X-Ray Emission in Galaxy Clusters

Abstract

Galaxy clusters are some of the largest structures in the visible Universe, on the order of 1-3 megaparsecs in size (~1023 meters). The process that creates these clusters and the usually strong magnetic fields within them is not well understood. Present in the center of these large scale structures is an extremely diffuse mixture of gases that emits electromagnetic radiation in the of radio waves and X-ray spectrum. It is known that, for some of these clusters, the strength of these emissions correlates well (i.e. clusters with strong X-ray emission have strong radio emission), but for many the radio emission drops significantly while the X-ray emission may still remain strong. This mechanism that causes this drop in radio is unknown, especially since much of this radio emission likely lies below the detection limit of modern radio telescopes. Using statistical image processing techniques, we sought to identify the presence of the diffuse radio emission that lies below the detection limit using observations from the Sydney University Molonglo Sky Survey of clusters in the Southern Sky, cross-referencing with X-ray images taken from . In this poster, I present a confirmation of a real detection of diffuse radio emission within these clusters. Unfortunately, the procedure used to detect this diffuse emission is unable to pinpoint which clusters, specifically, contain the diffuse emission, and which do not. Therefore, I also present attempts to narrow down which clusters contain this emission, and their correlation to the X-ray emission in each cluster. The results of this experiment serve to further the understanding of the formation and lifetime of galaxy clusters within the Universe, as well as better the methods used to observe and analyze them.