Tracing gas motions in the Centaurus cluster

Abstract

We apply the stochastic model of iron transport developed by Rebusco et al. to the Centaurus cluster. Using this model, we find that an effective diffusion coefficient D in the range 2 × 10²⁸-4 × 10²⁸cm²s^-1 can approximately reproduce the observed abundance distribution. Reproducing the flat central profile and sharp drop around 30-70kpc, however, requires a diffusion coefficient that drops rapidly with radius so that D > 4 × 10²⁸cm²s^-1 only inside about 25kpc. Assuming that all transport is due to fully developed turbulence, which is also responsible for offsetting cooling in the cluster core, we calculate the length- and velocity-scales of energy injection. These length-scales are found to be up to a factor of ~10 larger than expected if the turbulence is due to the inflation and rising of a bubble. We also calculate the turbulent thermal conductivity and find it is unlikely to be significant in preventing cooling.