Geoff Bicknell (Australian National University)

Radio-Mode Feedback -- Geoff Bicknell Colloquium

Marsfield Lecture Theatre

Abstract

The potential role of Radio Galaxies in providing feedback during the formation of bright galaxies has breathed new life into the study of radio galaxies. Both observations and theory are providing new insights into the way
in which young radio galaxies interact with their environment. In our theoretical program at Mt Stromlo, we have been been conducting 3D simulations of relativistic jets interacting with an inhomogeneous interstellar medium. We have mapped out an extensive parameter space consisting of jet power, filling factor and cloud sizes, with high resolution (~ 1 pc) simulations, with the aim
of determining the range of jet powers which are relevant to negative AGN feedback, i.e. the suppression of star formation.

Radio jet-powered bubbles lead to the dispersal of clouds in the galactic nucleus. We have determined the detailed physics of this dispersal process and the velocities of clouds that are produced by the simulations are consistent
with various observations of high redshift radio galaxies and CSS radio sources. So far it appears that the range of jet powers that are relevant to radio-mode feedback are in excess of 10^{43} > ergs s^{-1} and the ratio of the jet power to Eddington luminosity should exceed 10^{-4}. The morphology of our simulations are also strikingly similar to some well-known radio sources
including the iconic quasar 3C 48.