Formation and Evolution of sub-structures in tidal tails: Spherical dark matter haloes

TL;DR

This study compares theoretical predictions and simulations of star over-density formation in tidal tails of dwarf galaxies within different dark matter halo shapes, revealing asymmetries and establishing new relations.

Contribution

It demonstrates that the shape of dark matter halos (cored or cuspy) does not affect over-density formation, but uncovers asymmetries between tidal tail arms and relates over-density distance and size.

Findings

No difference in over-density formation between cored and cuspy halos.

Trailing arm grows faster than leading arm, showing asymmetry.

Established a relation between over-density distance and size.

Abstract

Recently a theory about the formation of over-densities of stars along tidal tails of globular clusters has been presented, this theory predicts the position and time of formation of such over-densities and was successfully tested with N-body simulations of globular clusters in a point mass galactic potential. In this work we present a comparison between this theory and our simulations using a dwarf galaxy orbiting two differently shaped dark matter halos to study the effects of a cored and a cuspy halo on the formation and evolution of tidal tails. We find no difference using a cuspy or a cored halo, however, we find an intriguing asymmetry between the leading and trailing arm of the tidal tails. The trailing arm grows faster than the leading arm. This asymmetry is seen in the distance to first over-density and its size as well. We establish a relation between the distance to the first over-density and the size of this over-density.