Long-Term Evolution of Magnetized Bubbles in Galaxy Clusters
Abstract
We have performed nonlinear ideal magnetohydrodynamic simulations of the long-term evolution of a magnetized low-density "bubble" plasma formed by a radio galaxy in a stratified cluster medium. It is found that about 3.5% of the initial magnetic energy remains in the bubble after ~8 × 109 yr, and the initial magnetic bubble expansion is adiabatic. The bubble can survive for at least 8 × 109 yr due to the stabilizing effect of the bubble magnetic field on Rayleigh-Taylor and Kelvin-Helmholtz instabilities, possibly accounting for "ghost cavities" as observed in Perseus A. A filament structure spanning about 500 kpc is formed along the path of bubble motion. The mean value of the magnetic field inside this structure is ~0.88 μG at ~8 × 109 yr. Finally, the initial bubble momentum and rotation have limited influence on the long-term evolution of the bubble.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2008
- DOI:
- 10.1086/592147
- arXiv:
- arXiv:0806.3717
- Bibcode:
- 2008ApJ...684L..57L
- Keywords:
-
- galaxies: jets;
- magnetic fields;
- methods: numerical;
- MHD;
- Astrophysics
- E-Print:
- 11 pages, 5 figures, accepted by ApJL. Minor changes according to the referee's report