Contribution
Polarimetry and Faraday Rotation of radio galaxies behind the lobes of Centaurus A
Presenter: Bryan Gaensler (University of Sydney)
Abstract: The lobes of Centaurus A have a maximum angular extent of almost 10°. The large projected area of these lobes has thus allowed us to carry out a unique experiment, in which we have used the Australia Telescope Compact Array to measure the polarisation and Faraday rotation of approximately 300 distant radio galaxies in the direction of Centaurus A. Approximately a third of these sources lie directly behind the lobes, while the remaining two-thirds have positions just outside the lobes, and allow us to account for foreground Faraday rotation in the Milky Way. I will present the first results from this “rotation measure grid” through Centaurus A – our analysis suggests enhanced fluctuations in Faraday rotation around the rim of the southern lobe, potentially demonstrating the presence of a skin of thermal gas swept up from the surrounding intra-cluster medium.