Publication: Spiral and Bar Instabilities Provoked by Dark Matter Satellites
All || By Area || By Year| Title | Spiral and Bar Instabilities Provoked by Dark Matter Satellites | Authors/Editors* | J. Dubinski, J.-R. Gauthier, L.M. Widrow, S. Nickerson |
|---|---|
| Where published* | In proceedings The Formation and Evolution of Disk Galaxies, eds. E. Corsini and J. Funes |
| How published* | Proceedings |
| Year* | 2008 |
| Volume | |
| Number | |
| Pages | 4 |
| Publisher | |
| Keywords | Galactic Dynamics; Spiral Galaxies; Dark Matter |
| Link | http://arxiv.org/abs/0802.3997 |
| Abstract |
We explore the secular dynamical evolution of an N-body model of M31 in the presence of a population of 100 dark matter satellites over 10 Gyr. The satellite population has structural and kinematic characteristics modelled to follow the predictions of Lambda-CDM cosmological simulations. Vertical disk heating is a small effect despite many interactions with the satellite population with only a 20% increase in vertical velocity dispersion sigma_z and the disk scale height z_d at the equivalent solar radius R = 2.5R_d . However, the stellar disk is noticeably flared after 10 Gyr with z_d nearly doubling at the disk edge. Azimuthal disk heating is much larger with sigma_R and sigma_z both increasing by 1.7x. However, in a control experiment without satellites dispersion increases by 1.5x suggesting that most of the effect is due to heating through scattering off of spiral structure excited by swing-amplified noise. Surprisingly, direct impacts of satellites on the disk can excite spiral structure with a significant amplitude and in some cases impacts close to the disk center also induce the bar instability. The large number of dark matter satellite impacts expected over a galaxy's lifetime may be a significant source of external perturbations for driving disk secular evolution. |
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