Stability of the Milky Way Satellite Galaxy Plane under the Influence of Neighbors

TL;DR

This study investigates how the gravitational influence of neighboring galaxies, especially M31, affects the stability of the Milky Way's satellite galaxy plane over billions of years.

Contribution

It introduces a model considering the time-varying, nonspherical gravitational potential including the quadrupole component from M31's influence.

Findings

Perturbations can significantly alter satellite trajectories beyond 100 kpc.

The stability of the satellite plane depends on M31's trajectory.

Such planar structures may only persist for a few billion years.

Abstract

Trajectories of test particles in a time-varying nonspherical gravitational potential model of our Galaxy are considered. The role of the quadrupole component of the potential, which at distances greater than 50 kpc is associated with the distribution of matter in the Galaxy's neighborhood (mainly with the influence of the galaxy M31), is studied. It is shown that perturbations of the potential created by the environment can significantly change the trajectories of particles at distances greater than 100 kpc from the Galactic center, but the magnitude of this effect depends on the still poorly known trajectory of the galaxy M31. For some variants of this trajectory, structures resembling a "thin plane" of satellite galaxies cannot exist for more than 2-3 billion years.