Spiral and Bar Instabilities Provoked by Dark Matter Satellites

Understand

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.