The collision between the Milky Way and Andromeda and the fate of their Supermassive Black Holes

TL;DR

This paper simulates the future collision of the Milky Way and Andromeda galaxies, focusing on the dynamics of their supermassive black holes and how initial conditions influence the merger timeline.

Contribution

It provides new insights into the dependence of galaxy merger timing and black hole evolution using direct N-body simulations with the HiGPUs code.

Findings

Merger likely occurs in 3-5 Gyrs under reliable scenarios.

Black holes may form a tight binary system post-merger.

The merger timeline depends on initial orbital parameters.

Abstract

Our Galaxy and the nearby Andromeda Galaxy (M31) form a bound system, even though the relative velocity vector of M31 is currently not well constrained. Their orbital motion is highly dependent on the initial conditions, but all the reliable scenarios imply a first close approach in the next 3-5 Gyrs. In our study, we simulate this interaction via direct N-body integration, using the HiGPUs code. Our aim is to investigate the dependence of the time of the merger on the physical and dynamical properties of the system. Finally, we study the dynamical evolution of the two Supermassive Black Holes placed in the two galactic centers, with the future aim to achieve a proper resolution to follow their motion until they form a tight binary system.