A Formation Scenario for the Disk of Satellites: Accretion of Satellites during Mergers

TL;DR

This paper proposes a new formation scenario for the Disk of Satellites (DoS) in galaxies, suggesting that satellite accretion during mergers can produce the observed thin, extended, rotating satellite structures.

Contribution

It introduces a novel merger-based formation mechanism for the DoS, emphasizing satellite accretion during galaxy coalescence as a key process.

Findings

Simulations show satellite populations can form a DoS during mergers.

Key parameters influence the formation of a flattened, rotating satellite structure.

The scenario explains DoS features consistent with observations.

Abstract

The Disk of Satellites (DoS) observed in the Andromeda galaxy is a thin and extended group of satellites, nearly perpendicular to the disk plane, that share a common direction of rotation about the centre of Andromeda. Although a DoS is also observed in the Milky Way galaxy, the prevalance of such structures in more distant galaxies remains controversial. Explanations for the formation of such DoSs vary widely from filamentary infall, or flattening due to the potential field from large scale structure, to galaxy interactions in a Mondian paradigm. Here we present an alternative scenario -- during a merger, a galaxy may bring its own satellite population when merging with another galaxy. We demonstrate how, under the correct circumstances, during the coalescence of the two galaxies, the satellite population can be spread into an extended, flattened structure, with a common direction of rotation about the merger remnant. We investigate the key parameters of the interaction, and the satellite population, that are required to form a DoS in this scenario.