Angular momentum transport, in the central region of the Galaxy
Leonid M. Ozernoy1,2, Alexei M. Fridman3,4, Peter L. Biermann5
1 Computational Sciences Institute and Department of Physics & Astronomy, George Mason U., Fairfax, VA 22030-4444, USA, email: ozernoy@science.gmu.edu
2Laboratory for Astronomy and Solar Physics, Goddard Space Flight Center, Greenbelt, MD 20771, USA, email: ozernoy@stars.gsfc.nasa.gov
3Institute of Astronomy, Russian Academy of Sciences, 48 Pyatnitskaya St., Moscow 109017, Russia, email: afridman@inasan.rssi.ru
4Moscow State University, 18 University Prospect, Moscow, 119899, Russia
5Max Planck Institut für Radioastronomie, Auf dem Hügel 69, P.O. Box 2024, D-53010, Germany, email: p165bie@mpifr-bonn.mpg.de
Paper: to appear in A&A
Abstract:
We discuss mechanisms for angular momentum transport in the clumpy
medium of the circumnuclear disk at the Galactic center. The viscosity due to
clump-clump collisions is found to be less than some critical viscosity;
this meets the conditions at which a collective mode of nonaxisymmetric
shear perturbations in the disk is able to grow
until going into the saturation regime where fully developed turbulence is
established. We find that the angular momentum transfer due to this
turbulent viscosity turns out to comparable to the transport due to magnetic
torques. Taken together, the turbulent and magnetic transfer of angular
momentum are able to provide the inflow of mass into the central parsec
with a rate of about 10-2Mo/yr, consistent with the available data.
Preprints available from the authors at OZERNOY@achamp.gsfc.nasa.gov
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or the raw TeX (no figures) if you click here.
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