Dissipative Dark Matter and the Andromeda Plane of Satellites

TL;DR

This paper proposes that dissipative dark matter within a galactic disk can explain the high mass-to-light ratios observed in the Andromeda satellite plane, suggesting a new mechanism for dark matter distribution during galaxy interactions.

Contribution

It introduces the idea that dissipative dark matter in a thin disk can produce high mass-to-light ratios in satellite galaxies, a novel explanation for their observed properties.

Findings

Dark matter in the galactic plane can be more tightly bound due to lower velocities.

Tidal forces can extract dark matter patches with high mass-to-light ratios.

Preliminary N-body results show ratios up to 30, pending full simulations.

Abstract

We show that dissipative dark matter can potentially explain the large observed mass to light ratio of the dwarf satellite galaxies that have been observed in the recently identified planar structure around Andromeda, which are thought to result from tidal forces during a galaxy merger. Whereas dwarf galaxies created from ordinary disks would be dark matter poor, dark matter inside the galactic plane not only provides a source of dark matter, but one that is more readily bound due to the dark matter's lower velocity. This initial N-body study shows that with a thin disk of dark matter inside the baryonic disk, mass-to-light ratios as high as O(30) can be generated when tidal forces pull out patches of sizes similar to the scales of Toomre instabilities of the dark disk. A full simulation will be needed to confirm this result.