AGN and the necessity of feedback.
There is now good observational evidence that some type of feedback process must operate within galaxies. Such a process has long been thought to exist on the basis of theoretical studies of galaxy formation. This feedback is responsible for regulating the rate of star formation and thereby preventing the formation of an overabundance of low-mass galaxies. There is gathering evidence that this feedback process must somehow involve the supermassive black holes thought to dwell in the centres of galaxies.
Benson
Andrew J
AJ
Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH, UK. abenson@astro.ox.ac.uk