Phase-space correlation in stellar streams of the Milky Way halo: The clash of Kshir and GD-1

TL;DR

This paper reports the discovery of a new stellar stream called Kshir that is spatially and kinematically correlated with the known GD-1 stream in the Milky Way halo, suggesting a shared origin or interaction.

Contribution

The paper introduces Kshir, a new stellar stream, and explores its correlation with GD-1, proposing a dark matter sub-halo accretion scenario to explain their phase-space entanglement.

Findings

Kshir is a 70-degree long stellar stream in the Milky Way halo.

Kshir and GD-1 are at similar distances and show remarkable kinematic correlation.

A shared dark matter sub-halo origin may explain their phase-space relationship.

Abstract

We report the discovery of a 70-degree long stellar stream in the Milky Way halo, which criss-crosses the well known "GD-1" stream. We show that this new stellar structure ("Kshir") and GD-1 lie at similar distance, and are remarkably correlated in kinematics. We propose several explanations for the nature of this new structure and its possible association with GD-1. However, a scenario in which these two streams were accreted onto the Milky Way within the same dark matter sub-halo seems to provide a natural explanation for their phase-space entanglement, and other complexities of this coupled-system.