Evans, Daniel

Panchromatic Observations of the Nuclei of z<0.5 3CRR Radio Galaxies: Implications for Feeding, Feedback, and Black Hole Spin.

Author list: Daniel Evans, Mark Birkinshaw, Diana Worrall, David Garofalo, Martin Hardcastle, Judith Croston, Ralph Kraft, Rita Sambruna

We present a radio through X-ray study of the nuclei of 3CRR radio galaxies at z<0.5. This unique data set allows us to answer three key questions about radio-loud AGN: (1) What is the origin of X-ray emission? We show that the X-ray emission from low-excitation radio galaxies is dominated by a parsec-scale jet and shows no evidence for a torus. High excitation radio galaxies, on the other hand, are dominated by luminous accretion disks. (2) How does accretion take place? By estimating the kinetic jet power, we show that Bondi accretion of the hot IGM can power the majority of LERGs, but not the most powerful of these. The Bondi paradigm fails altogether for HERGs. (3) How are jets powered? We next consider models for extracting jet power from rotating black holes. We demonstrate that both the jet power and time evolution of radio-loud AGN fit into a model in which black hole spin varies from retrograde to prograde with respect to the accreting material.