2003/12/18 by Luca Ciotti, L. Ciotti, J. P. Ostriker +1 · 1 citation
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Heat Transfer Mechanisms #astro-ph
paper · pdf · doi:10.1063/1.1718482
6 pages, 1 figure, to appear in "Plasmas in the Laboratory and in the Universe: new insights and new challenges", G. Bertin, D. Farina, R. Pozzoli eds., AIP Conference Proceedings
arxiv created 2003/12/18 · openalex publication_date 2004/01/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Recent observations by Chandra and XMM‐Newton demonstrate that the central gas in “cooling flow” galaxy clusters has a mass cooling rate that decreases rapidly with decreasing temperature. This contrasts the predictions of a steady state cooling flow model. On the basis of these observational results, the gas can be in a steady state only if a steady temperature dependent heating mechanism is present; alternatively the gas could be in an unsteady state, i.e., heated intermittently. Intermittent heating can be produced by accretion on the supermassive black hole residing in the central cluster galaxy, via Compton heating. This mechanism can be effective provided that the radiation temperature of the emitted spectrum is higher than the gas temperature. Here we explore whether this heating mechanism can be at the origin of the enigmatic behavior of the hot gas in the central regions of “cooling flow” clusters. Although several characteristics of Compton heating appear attractive in this respect, we find that the fraction of absorbed heating for realistic gas and radiation temperatures falls short by two orders of magnitude of the required heating.