This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: (of course) models in which the stars are all very low mass and conveniently unobservable, but the role of nonradial flow and magnetic fields may well defeat those last few kiloparsecs. It has also been wdely suggested that AGN outbursts heat the IC sufficiently to dafeat cooling flows; evidence includes finding places where the radio plasma from double sources has shoved the hot gas around, and waves indicating kinetic-energy input. Cluster X-ray emission is perhaps a better tracer of dynamical evolution than galaxy counts, since it is smooth and not limited by galaxy statistics. This is also the technique of choice for finding distant clusters (as extended X-ray sources) since confusion at faint magnitudes makes optical identification difficult and unreliable. Note that the total mass of gas usually exceeds that in stars for a typical cluster....
View Full Document