2007/07/30 by Woong-Tae Kim · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Cooling flow #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy merger #Interacting galaxy #Intracluster medium #Kinetic energy #Turbulence #Velocity dispersion #astro-ph
paper · pdf · doi:10.1086/521950
12 pages including 3 figures, To appear in ApJL
arxiv created 2007/07/30 · openalex publication_date 2007/09/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using three-dimensional hydrodynamic simulations, we investigate heating and turbulence driving in an intracluster medium (ICM) by orbital motions of galaxies in a galaxy cluster. We consider N g member galaxies on isothermal and isotropic orbits through an ICM typical of rich clusters. An introduction of the galaxies immediately produces gravitational wakes, providing perturbations that can potentially grow via resonant interaction with the background gas. When N M 11 ≲ 100, where M 11 is each galaxy mass in units of 10 11 M ☉ , the perturbations are in the linear regime and the resonant excitation of gravity waves is efficient in generating kinetic energy in the ICM, resulting in the velocity dispersion σ v ~ 2.2 N M 11 km s -1 . When N M 11 ≳ 100, on the other hand, nonlinear fluctuations of the background ICM destroy galaxy wakes and thus render resonant excitation weak or absent. In this case, the kinetic energy saturates at the level corresponding to σ v ~ 220 km s -1 . The angle-averaged velocity power spectra of turbulence driven in our models have slopes in the range of -3.7 to -4.3. With the nonlinear saturation of resonant excitation, none of the cooling models considered are able to halt the cooling catastrophe, suggesting that the galaxy motions alone are unlikely to solve the cooling flow problem.