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Y. Fujita, C. L. Sarazin (University of Virginia)
We present the results of a Chandra observation of the central region of the cluster Abell 133. This cluster has a filamentary radio relic. The X-ray image shows that the distribution of low temperature gas at the cluster center is not smooth and symmetric with respect to the central cD galaxy. Moreover, a plume of X-ray emission extends from the galaxy to the NW. This plume extends in the direction of and partly overlaps the radio relic. The spectral analysis shows that the plume consists of low temperature thermal gas.
We considered two possible origins of the plume:
\noindent 1. Kelvin-Helmholtz Instability: The complex X-ray structure may show that a Kelvin-Helmholtz (KH) instability is developing between cold gas around cD galaxy moving to the SE and the surrounding hot ICM. In this case, the cD galaxy must be moving with a velocity of >300\rm\; km\; s-1. The critical velocity for the KH Instability is a few times smaller than those for A2142 and A3667 that have clear cold fronts.
\noindent 2. Uplifted Gas by a Buoyant Bubble: Recently, Churazov et al. (2001) showed that a buoyant bubble produced by AGN activities can uplift cold gas at the cluster center. For A133, the bubble may be radio plasma forming the radio relic and may uplift the plume. The age of radio relic is estimated to be 5\times 107~yr (Slee et al. 2001). The velocity of the bubble expected from the age (700\rm\; km\; s-1) is consistent with that numerically predicted by Churazov et al. (2001).
Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Numbers GO1-2122X and GO1-2123X, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-39073.