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Issue A&A Volume 419, Number 3, June I 2004 Page(s) 941 - 948 Section Galactic structure, stellar clusters and populations DOI 10.1051/0004-6361:20040098

A&A 419, 941-948 (2004)
DOI: 10.1051/0004-6361:20040098

Density waves in the shearing sheet

IV. Interaction with a live dark halo

B. Fuchs

Astronomisches Rechen-Institut, Mönchhofstrasse 12-14, 69120 Heidelberg, Germany
(Received 2 June 2003 / Accepted 19 February 2004)

Abstract
It is shown that if the self-gravitating shearing sheet, a model of a patch of a galactic disk, is embedded in a live dark halo, this has a strong effect on the dynamics of density waves in the sheet. I describe how the density waves and the halo interact via halo particles either on orbits in resonance with the wave or on non-resonant orbits. Contrary to expectation the presence of the halo leads to a very considerable enhancement of the amplitudes of the density waves in the shearing sheet. This effect appears to be the equivalent of the recently reported enhanced growth of bars in numerically simulated stellar disks embedded in live dark halos. Finally I discuss the transfer of linear momentum from a density wave in the sheet to the halo and show that it is mediated only by halo particles on resonant orbits.

Key words: galaxies: kinematics and dynamics -- galaxies: spiral

© ESO 2004

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