Stability of satellite planes in M31 II: effects of the dark subhalo population
Abstract
The planar arrangement of nearly half the satellite galaxies of M31 has been a source of mystery and speculation since it was discovered. With a growing number of other host galaxies showing these satellite galaxy planes, their stability and longevity have become central to the debate on whether the presence of satellite planes are a natural consequence of prevailing cosmological models, or represent a challenge. Given the dependence of their stability on host halo shape, we look into how a galaxy plane's dark matter environment influences its longevity. An increased number of dark matter subhaloes results in increased interactions that hasten the deterioration of an already-formed plane of satellite galaxies in spherical dark haloes. The role of total dark matter mass fraction held in subhaloes in dispersing a plane of galaxies presents non-trivial effects on plane longevity as well. But any misalignment of plane inclines to major axes of flattened dark matter haloes lead to their lifetimes being reduced to ≤3 Gyr. Distributing ≥40 per cent of total dark mass in subhaloes in the overall dark matter distribution results in a plane of satellite galaxies which is prone to change through the 5-Gyr integration time period.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2018
- DOI:
- 10.1093/mnras/stx2483
- arXiv:
- arXiv:1709.08010
- Bibcode:
- 2018MNRAS.473.2212F
- Keywords:
-
- galaxies: haloes;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 11 pages, 9 figures, accepted to MNRAS September 22 2017