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| Paper: |
Spiral and Bar Instabilities Provoked by Dark Matter Satellites |
| Volume: |
396, Formation and Evolution of Galaxy Disks |
| Page: |
321 |
| Authors: |
Dubinski, J.; Gauthier, J.-R.; Widrow, L.; Nickerson, S. |
| Abstract: |
We explore the secular dynamical evolution of an N-body model of M 31 in the presence of a population of 100 dark matter satellites over 10 Gyr. The satellite population has structural and kinematic characteristics modeled to follow the predictions of ΛCDM 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 σz and the disk scale height zd at the equivalent solar radius R = 2.5 Rd. However, the stellar disk is noticeably flared after 10 Gyr with zd nearly doubling at the disk edge. Azimuthal disk heating is much larger with σR and σz both increasing by 1.7×. However, in a control experiment without satellites dispersion increases by 1.5× 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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