2009/03/02 by Edward C. D. Pope
Engineering · Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy groups and clusters #Intracluster medium #Observable #Space Technology and Applications #Star formation #Velocity dispersion #astro-ph.GA
paper · pdf · doi:10.1111/j.1365-2966.2009.14714.x
Accepted for publication in MNRAS, 11 pages, 2 figures and 2 tables
arxiv created 2009/03/02 · openalex publication_date 2009/04/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have constructed an analytical model of active galactic nuclei (AGN) feedback and studied its implications for elliptical galaxies and galaxy clusters. The results show that momentum injection above a critical value will eject material from low-mass elliptical galaxies, and leads to an X-ray luminosity, LX, that is ∝σ8−10, depending on the AGN fuelling mechanism, where σ is the velocity dispersion of the hot gas. This result agrees well with both observations and semi-analytic models. In more massive ellipticals and clusters, AGN outflows quickly become buoyancy dominated. This necessarily means that heating by a central cluster AGN redistributes the intracluster medium (ICM) such that the mass of hot gas, within the cooling radius, should be ∝LX(< rcool)/[g(rcool)σ], where g(rcool) is the gravitational acceleration at the cooling radius. This prediction is confirmed using observations of seven clusters. The same mechanism also defines a critical ICM cooling time of ∼0.5 Gyr, which is in reasonable agreement with recent observations showing that star formation and AGN activity are triggered below a universal cooling time threshold.