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 subhalos results in increased interactions that hasten the deterioration of an already-formed plane of satellite galaxies in spherical dark halos. The role of total dark matter mass fraction held in subhalos in dispersing a plane of galaxies present non trivial effects on plane longevity as well. But any misalignments of plane inclines to major axes of flattened dark matter halos lead to their lifetimes being reduced to < 3 Gyrs. Distributing > 40% of total dark mass in subhalos in the overall dark matter distribution results in a plane of satellite galaxies that is prone to change through the 5 Gyr integration time period.

11 pages, 9 figures, accepted to MNRAS September 22 2017

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Cited by in corpus (5)

• Planes of satellites around Milky Way/M31-mass galaxies in the FIRE simulations and comparisons with the Local Group
• The Hubble Space Telescope Survey of M31 Satellite Galaxies I. RR Lyrae-based Distances and Refined 3D Geometric Structure
• Evolution of galactic planes of satellites in the EAGLE simulation
• Two major accretion epochs in M31 from two distinct populations of globular clusters
• The imprint of galaxy mergers on satellite planes in a cosmological context