AAS 205th Meeting, 9-13 January 2005
Session 75 Galaxy Clusters and Groups I
Oral, Tuesday, January 11, 2005, 10:00-11:30am, Pacific 2/3

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[75.01] Giant X-ray Cavities and Large Scale Shocks in a Distant Galaxy Cluster

B.R. McNamara (Ohio U.), P.E.J. Nulsen (CfA), M.W. Wise (MIT-CSR), D.A. Rafferty (Ohio U.), C. Carilli, C.L. Sarazin (NRAO), E.L. Blanton (Boston U.)

We report the discovery of a pair of giant cavities, each nearly 200 kpc in diameter, embedded in the gaseous halo of the redshift z=0.216 galaxy cluster MS0735.6+7421. The cavities appear as surface brightness depressions in an image of the cluster taken with the Chandra X-ray Observatory. The cavities are filled with radio emission and are bounded by an elliptical shock structure resembling a ``radio cocoon.'' The shock's energy ~6\times 1061 erg and 100 Myr age make it the most energetic AGN outburst known. The cavities are depositing approximately 2/3 keV per particle of heat throughout the cluster, enough to quench a large cooling flow for several Gyr and to heat the entire cluster. The accreted mass onto the supermassive black hole at the center of the cD galaxy required to power the outburst is ~3\times 108~{\rm M\odot}, implying the black hole has grown substantially in the past 100 Myr.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.