AAS 205th Meeting, 9-13 January 2005
Session 32 The Galactic Center
Oral, Monday, January 10, 2005, 10:00-11:30am, Pacific 2/3

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[32.01] TeV Emission from the Black-Hole Plerion at the Galactic Center

C.D. Dermer, A. Atoyan (NRL)

The HESS collaboration recently reported the detection of TeV \gamma-ray emission coincident with Sgr~A\ast. In the context of other Galactic Center (GC) observations, this points to the following scenario: In the extreme advection-dominated accretion flow (ADAF) regime of the GC black hole (BH), synchrotron radio/sub-mm emission of ~ 100 \,\rm MeV electrons emanates from an inefficiently radiating turbulent magnetized corona within 20 R\rm S (Schwarzschild radii) of the GCBH. Electrons are accelerated in this ADAF through second-order Fermi processes by MHD turbulence. Closer to the innermost stable orbit of the ADAF, instabilities and shocks within the flow inject power-law electrons through first-order Fermi acceleration to make synchrotron X-ray flares observed with Chandra, XMM, and INTEGRAL. A subrelativistic MHD wind subtending an ~ 1\,\rm sr cone with power \gtrsim 1037\,erg\,s-1 is driven by the ADAF from the vicinity of the GCBH. Electrons accelerated at the wind termination shock at \gtrsim 1016.5\,cm from the GCBH Compton-scatter ADAF and FIR dust emission to TeV energies. The synchrotron radiation of these electrons produces the quiescent X-ray plerionic source resolved by Chandra. The radio counterpart of the TeV/X-ray plerion, formed when the injected electrons cool on timescales of \gtrsim 104\,\rm yrs, could explain the origin of the nonthermal radio emission in the two-sided bar of the radio nebula Sgr A West.

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The author(s) of this abstract have provided an email address for comments about the abstract: dermer@gamma.nrl.navy.mil

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