20 November 2003

Speaker: Mitchell Begelman (Univ. of Colorado Boulder)

Title: Cooling Flows Sing the Blues

Abstract: Despite copious production of X-rays, gas in the central regions of clusters of galaxies appears to be neither cooling nor flowing at the rate predicted by cooling flow models. Energy input by AGN is a prime candidate for offsetting the radiative losses. I will discuss the physics of "effervescent heating" and describe the evidence that acoustic energy injected by AGN can quench cooling flows. I will also discuss the possibility that AGN heating is responsible for the "entropy floor" in galaxy clusters.

References for students:

1. M. C. Begelman 2003, astro-ph/0303040
2. A. C. Fabian et al. 2003a, MNRAS, 344,43
3. A. C. Fabian et al. 2003b, MNRAS, 344, 48
4. M. Ruszkowski and M. C. Begelman 2002, ApJ, 581,223
5. M. Ruszkowski, M. Brueggen and M. C. Begelman 2003, astro-ph/031076