2004/07/31 by Noam Soker, Fabio Pizzolato · 1 citation
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1086/428112
published as Astrophys.J. 622 (2005) 847-852 · The Astrophysical Journal, in press
arxiv created 2004/12/14 · openalex publication_date 2005/03/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We propose a scenario in which a large fraction or even most of the gas cooling to low temperatures of T < 10 4 K in cooling flow clusters gains energy directly from the central black hole. Most of the cool gas is accelerated to nonrelativistic high velocities, v j ≃ 10 3 -10 4 km s -1 , after flowing through, or close to, an accretion disk around the central black hole. A poorly collimated wind (or a pair of poorly collimated opposite jets) is formed. According to the proposed scenario, this gas inflates some of the X-ray-deficient bubbles, such that the average gas temperature inside these bubbles (cavities) in cooling flow clusters is kT b ≲ 100 keV. A large fraction of these bubbles will be very faint or undetectable in the radio. The bright rims of these weak smaller bubbles will appear as ripples. We suggest that the X-ray ripples observed in the Perseus cluster, for example, are not sound waves but rather the rims of radio-faint weak bubbles that are only slightly hotter than their environment. This scenario is incorporated into the moderate cooling flow model; although not a necessary ingredient in that model, it brings it to better agreement with observations. A cooling flow does exist in the moderate cooling flow model, but the mass cooling rate is ≲10% of that in old versions of cooling flow models.