Can a Satellite Galaxy Merger Explain the Active Past of the Galactic Center?

TL;DR

This paper explores whether a satellite galaxy merger could explain the Milky Way's past active phase, suggesting that such an event might have triggered star formation and black hole activity in the Galactic Center.

Contribution

It proposes a novel scenario linking satellite galaxy infall and merger events to the historical activity observed in the Galactic Center.

Findings

Satellite galaxy infall could have occurred starting at redshift 10.

Merger with an intermediate mass black hole may have triggered past activity.

The model aligns with forensic evidence of past star formation and accretion in the GC.

Abstract

Observations of the Galactic Center (GC) have accumulated a multitude of "forensic" evidence indicating that several million years ago the center of the Milky Way galaxy was teaming with starforming and accretion-powered activity -- this paints a rather different picture from the GC as we understand it today. We examine a possibility that this epoch of activity could have been triggered by the infall of a satellite galaxy into the Milky Way which began at the redshift of 10 and ended few million years ago with a merger of the Galactic supermassive black hole with an intermediate mass black hole brought in by the inspiralling satellite.