8th HEAD Meeting, 8-11 September, 2004
Session 2 Galaxy Clusters and the Intergalactic Medium
Poster, Wednesday, September 8, 2004, 9:00am-10:00pm

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[2.01] A Detailed Analysis of the AGN/ICM Interaction in Hydra A

M. W. Wise (MIT), B. R. McNamara (Ohio Univ.), P. E. J. Nulsen, L. P. David (CfA)

We present results from a new 200 ksec Chandra observation of the Hydra A cluster of galaxies. As in the Perseus cluster, Chandra has observed large X-ray cavities or bubbles associated with the central radio source in Hydra A. Unlike its more famous cousin, however, the central radio source in Hydra A is an order of magnitude stronger, making it an ideal laboratory for studying the interactions between the central AGN and the surrounding intracluster medium (ICM). Here we will present detailed maps of the physical properties of the X-ray emitting gas, and discuss the constraints they imply for models of AGN/ICM interactions in cluster cores. With the current data set, we can resolve the temperature and abundance structure of the cavities in Hydra A on scales of 3 kpc. Our analysis confirms the presence of cool gas (T ~3 keV) associated with the rims of the cavities, and we will discuss the consequences this result has for theories of AGN-driven shocks and estimates of Hydra A's evolution/age. This cool gas associated with the cavity rims exhibits an elemental abundance enhancement ~2 greater than the surrounding ICM, consistent with previous suggestions that radio bubbles convectively loft metal-rich gas from the core into the outer parts of the cluster. We also find that the mechanical energy in the cavities is enough to balance radiative cooling in the core of Hydra A. We discuss this result in light of recent evidence for truncated cooling in cluster cooling cores.

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.