Published online by Cambridge University Press: 03 June 2010
Accretion onto the massive black hole at the centre of a galaxy can feed energy and momentum into its surroundings via radiation, winds, and jets. Feedback due to radiation pressure can lock the mass of the black hole onto the MBH–σ relation, and shape the final stellar bulge of the galaxy. Feedback due to the kinetic power of jets can prevent massive galaxies greatly increasing their stellar mass by heating gas, which would otherwise cool radiatively. The mechanisms involved in cosmic feedback are discussed and illustrated with observations.