PHASE-SPACE CORRELATION IN STELLAR STREAMS OF THE MILKY WAY HALO: THE CLASH OF KSHIR AND AND GD-1

Khyati Malhan , Rodrigo A Ibata (1) , Raymond G Carlberg , Michele Bellazzini , Benoit Famaey (1) , Nicolas Martin (1)

1 ObAS - Observatoire astronomique de Strasbourg

We report the discovery of a 70 • 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.

Domaines: Physique [physics]; Astrophysique [astro-ph]

Khyati Malhan, Rodrigo A Ibata, Raymond G Carlberg, Michele Bellazzini, Benoit Famaey, et al.. PHASE-SPACE CORRELATION IN STELLAR STREAMS OF THE MILKY WAY HALO: THE CLASH OF KSHIR AND AND GD-1. The Astrophysical journal letters, 2019, 886 (1), pp.L7. ⟨10.3847/2041-8213/ab530e⟩. ⟨hal-02984950⟩