AAS Meeting #193 - Austin, Texas, January 1999
Session 38. Galaxy Clusters
Display, Thursday, January 7, 1999, 9:20am-6:30pm, Exhibits Hall 1

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[38.11] The Virgo Cluster and the M87 Radio Halo: Outflow, not Cooling Flow

F. N. Owen (NRAO), J. A. Eilek (NM Tech), N. E. Kassim (NRL)

We present new 90cm VLA observations of the 80 kpc radio structure of M87. The new images show a spectacular, complex structure extending from the region containing the jet out into two bubble-like lobes. The brightest parts of the radio emission suggest a poorly collimated flow from the inner lobes out into the bubbles. The many bright, curved features in this flow appear to be shocks which must be heating the external medium as well as blowing up the bubbles. The extremely filamented source requires a very unfilled radio structure which implies that the minimum energy magnetic fields have been underestimated. Combined with recent models of the jet and inner lobes, the new image suggests that more energy is being pumped into the bubbles by the activity in the central black hole than is being radiated away in X-rays from the same volume, which has been modeled as a cooling flow. Thus these observations suggest that the central black hole is powering the activity seen over this large region, not the slow infall of the hot cluster medium.


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