2008/06/19 by Evan Scannapieco, Marcus Brüggen
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Cascade #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy formation and evolution #Hydrostatic equilibrium #Intracluster medium #Structure formation #Turbulence #astro-ph
paper · pdf · doi:10.1086/591228
23 pages, 19 figures, ApJ, in press, full resolution version available at http://scannapieco.asu.edu/clusterpaper.pdf
arxiv created 2008/06/19 · openalex publication_date 2008/10/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Hot, underdense bubbles powered by active galactic nuclei (AGNs) are likely to play a key role in halting catastrophic cooling in the centers of cool-core galaxy clusters. We present three-dimensional simulations that capture the evolution of such bubbles, using an adaptive mesh hydrodynamic code, FLASH3, to which we have added a subgrid model of turbulence and mixing. While pure hydro simulations indicate that AGN bubbles are disrupted into resolution-dependent pockets of underdense gas, proper modeling of subgrid turbulence indicates that this is a poor approximation to a turbulent cascade that continues far beyond the resolution limit. Instead, Rayleigh-Taylor instabilities act to effectively mix the heated region with its surroundings, while at the same time preserving it as a coherent structure, consistent with observations. Thus, bubbles are transformed into hot clouds of mixed material as they move outward in the hydrostatic intracluster medium (ICM), much as large airbursts lead to a distinctive "mushroom cloud" structure as they rise in the hydrostatic atmosphere of Earth. Properly capturing the evolution of such clouds has important implications for many ICM properties. In particular, it significantly changes the impact of AGNs on the distribution of entropy and metals in cool-core clusters such as Perseus.