The galaxy cluster environments of wide angle tail radio sources

Abstract

Double-lobed radio sources result from high-speed plasma jets produced as matter accretes onto the central black hole within an elliptical galaxy. Those which display a characteristic jet-hotspot-lobe transition and possess an intermediate radio power are called Wide Angle Tail radio sources (WATs). WATs are typically associated with the luminous central galaxy within a cluster of galaxies and usually appear bent due to their interaction with the hot, X-ray bright intracluster medium (ICM). They have been proven to be good tracers of high redshift clusters where X-ray and optical observations are more difficult. Nonetheless, it has been unclear whether a WATs presence is directly linked to cluster conditions on the global scale (i.e., cluster mergers or clusters with cores that are cooling, providing fuel for the central black hole). In an effort to characterize the global X-ray properties of WAT clusters, I have assembled a sample of 12 WAT systems observed with the Chandra X-ray Observatory. I examine the distribution of substructure, temperature, abundance, density and pressure within the ICM. I compare the results with those of an identical analysis of two WAT-less cluster samples, those with known mergers and those with cool cores. I find the majority of WAT clusters display some merger signatures and many show evidence of cool/high metallicity gas within 100 kpc of the WAT host galaxy. Some WATs are found in relaxed clusters with intact cool cores and these are best suited to be included in certain cluster cosmological studies. I observe that clusters with the highest central densities and pressures host WATs with the shortest flare radii. I have performed a more in-depth analysis of the X-ray and radio properties of two WAT clusters which appear to exhibit contrasting levels of dynamical activity and WAT source bending (Abell562 and Abell1446). I conclude that merger-induced ICM ram pressure is the primary factor in shaping both WATs. By examining the conditions within the cores of these systems and the interaction between the ICM and radio sources, I am able to constrain the internal properties of the jets and lobes.