Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-02-08
Mon.Not.Roy.Astron.Soc. 359 (2005) 493-503
Astronomy and Astrophysics
Astrophysics
12 pages, 5 figures, accepted by MNRAS
Scientific paper
10.1111/j.1365-2966.2005.08902.x
The buoyant rise of hot plasma bubbles inflated by AGN outflows in galaxy clusters can heat the cluster gas and thereby compensate radiative energy losses of this material. Numerical simulations of this effect often show the complete disruption of the bubbles followed by the mixing of the bubble material with the surrounding cluster gas due to fluid instabilities on the bubble surface. This prediction is inconsistent with the observations of apparently coherent bubble structures in clusters. We derive a general description in the linear regime of the growth of instabilities on the surface between two fluids under the influence of a gravitational field, viscosity, surface tension provided by a magnetic field and relative motion of the two fluids with respect to each other. We demonstrate that Kelvin-Helmholtz instabilities are always suppressed, if the fluids are viscous. They are also suppressed in the inviscid case for fluids of very different mass densities. We show that the effects of shear viscosity as well as a magnetic fields in the cluster gas can prevent the growth of Rayleigh-Taylor instabilities on relevant scale lengths. R-T instabilities on pc-scales are suppressed even if the kinematic viscosity of the cluster gas is reduced by two orders of magnitude compared to the value given by Spitzer for a fully ionised, unmagnetised gas. Similarly, magnetic fields exceeding a few microG result in an effective surface tension preventing the disruption of bubbles. For more massive clusters, instabilities on the bubble surface grow faster. This may explain the absence of thermal gas in the north-west bubble observed in the Perseus cluster compared to the apparently more disrupted bubbles in the Virgo cluster.
Fangohr Hans
Kaiser Christian R.
Pavlovski Georgi
Pope Edward C. D.
No associations
LandOfFree
The stability of buoyant bubbles in the atmospheres of galaxy clusters does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The stability of buoyant bubbles in the atmospheres of galaxy clusters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The stability of buoyant bubbles in the atmospheres of galaxy clusters will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-27787