Substructures in Minor Mergers' Tidal Streams

TL;DR

This study investigates the formation of substructures like stellar clusters within tidal streams from minor galactic mergers, using simulations to understand their properties and the role of gas and dark matter.

Contribution

It demonstrates that gas presence leads to long-lasting substructures in tidal streams, providing insights into their formation and dark matter's influence.

Findings

Gas is essential for stable substructure formation.

Long-lived clumps can form in tidal streams with gas.

Evidence suggests dark matter's role in these structures.

Abstract

In this work, we explore the idea that substructures like stellar clusters could be formed from the tidal stream produced in galactic minor mergers. We use $N$-body and SPH simulations of satellite galaxies interacting with a larger galaxy. We study the distribution of mass in streams to identify overdensity regions in which a substructure could be formed. We found that without gas, no substructure formed as none of the overdensities shows a definite morphology nor dynamical stability. Including gas we found that several clumps appear and proved to be real long standing physical structures ($t \geq$ 1 Gyr). We analyzed the orbits, ages and masses of these structures, finding its correspondence with the halo subsystems. We conclude that it is possible to form cluster-like structures from the material in tidal streams and found evidence in favour of the presence of dark matter in these systems.