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1999ApJ...524..634L - Astrophys. J., 524, 634-649 (1999/October-3)
Eccentric behavior of disk galaxies.
LOVELACE R.V.E., ZHANG L., KORNREICH D.A. and HAYNES M.P.
Abstract (from CDS):
We first study the eccentric motion of a disk consisting of two rings of different radii but equal mass, Md/2. For small Md the two rings are stable, but for Md larger than a threshold value the rings are unstable with a dynamical timescale growth. For Md sufficiently above this threshold, the instability acts to decrease the angular momentum of the inner ring, while increasing that of the outer ring. The instability results from the merging positive and negative energy modes with increasing Md. Second, we analyze the eccentric motion of one ring interacting with a radially shifted central mass. In this case instability sets in above a threshold value of the central mass (for a fixed ring mass), and it acts to increase the angular momentum of the central mass (which therefore rotates in the direction of the disk matter), while decreasing the angular momentum of the ring.
Third, we study the eccentric dynamics of a disk with an exponential surface density distribution represented by a large number of rings. The inner part of the disk is found to be strongly unstable. Angular momentum of the rings is transferred outward and to the central mass if present, and a trailing one-armed spiral wave is formed in the disk. Fourth, we analyze a disk with a modified exponential density distribution where the density of the inner part of the disk is reduced. In this case we find much slower, linear growth of the eccentric motion. A trailing one-armed spiral wave forms in the disk and becomes more tightly wrapped as time increases. The motion of the central mass if present is small compared with that of the disk.
Abstract Copyright: ∼
Journal keyword(s): Celestial Mechanics, Stellar Dynamics - Galaxies: Kinematics and Dynamics - Galaxies: Structure
Simbad objects: 8
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