Dark Matter Accounts for Perturbation in the GD-1 Stellar Stream

TL;DR

This paper investigates a perturbation in the GD-1 stellar stream, suggesting it was likely caused by a dark matter clump, and uses simulations to explore dark matter distribution in the Milky Way.

Contribution

It introduces a model linking stream gaps to dark matter subhalos and identifies the first potential impact of a dark matter clump on GD-1.

Findings

Detected a significant gap in GD-1 caused by perturbation.

Simulations suggest the impact was likely due to dark matter rather than globular clusters.

Provides a method to map dark matter distribution using stellar stream perturbations.

Abstract

The longest recognized stellar stream in the Milky Way Galaxy has an expanse of over more than half the north sky. There was a physical disturbance within the stream, 500 million years ago, which could have been the scar of a dark matter collision. Due to its proximity to the galactic center, the GD-1 stellar stream can act as an antenna for gravitational perturbations. In 2018, a significant gap in GD-1 was discovered due to perturbation. A stream gap occurs when a massive object collides with the stellar stream. Based on the chasm location and width, we can guess when and where the impact occurred. Using globular cluster sky coordinates and simulated galactocentric distributions, we calculated how close each globular cluster came to the GD-1 stream. This would be the first time a globular cluster has come close enough to the GD-1 stream to impact another object. Clusters, on the other hand, rarely approach GD-1, indicating that it was struck by something more exotic, like a clump of dark matter, when discovered. A simulation and theoretical model were created to better understand the GD-1 stellar stream behavior. These details can be used to map the large-scale distribution of dark matter in our galaxy as well as the small-scale structure of dark matter in the host galaxies of the streams. Examination of stellar streams and detection of subhalos will not only confirm the presence of dark matter but also reveal information about its particle nature.