AAS 200th meeting, Albuquerque, NM, June 2002
Session 22. Extra Galactic Magnetic Fields: Their Origin and Manifestation through Structure of Quasars, Radio Lobes and within Clusters
Special Session Oral, Monday, June 3, 2002, 10:00-11:30am, La Cienega

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[22.01] Source of the Largest Extragalactic Magnetic Field Energies

P.P. Kronberg (LANL), Q.W. Dufton (University of Toronto), H. Li, S.A. Colgate (LANL)

The recently implied ubiquity of ~\,108\, M\odot central black holes (GBH) in large elliptical galaxies raises the question ``How much of the black hole energy that is released can we independently and quantitively measure in the surrounding IGM?''. A recent source-by-source analysis by us to answer this question determined that the best IGM calorimeters for this purpose are the largest (~0.5 to 5\,Mpc), not the most radio luminous extragalactic radio sources. These occur in relatively rarified IGM environments away from cluster cores. The upper bound of the energy content of the synchrotron-emitting lobes, much of which is magnetic, is ~8 \times 1060ergs, -- a significant fraction of the GBHs' gravitational binding energy. There are reasons why this global total energy estimate may even be conservative. The proximity of this number to the AGNs' total (gravitational) energy reservoir, and hence with the total radiated energy over all bands (which escapes at c) has many implications that are not yet understood in detail. The captured, i.e. magnetic, energy which propagates away much more slowly, constitutes a very large amount of retained energy in the locality of the host galaxy. For a cluster member AGN, this magnetic energy will be deposited within the host galaxy cluster. For a ``field'' radio galaxy, it will remain captured within ~ a Mpc.

We briefly discuss the wideranging implications that this hitherto hidden, intergalactic magnetic energy has for subsequent galaxy formation on these scales, and some implications for the IGM energetics of galaxy clusters.

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.