Stellar streams in the deforming dark matter haloes of the Milky Way and the LMC

Nov 07, 2022 - 11:00 am to 12:00 pm

Campus, Varian 355

Sophia Lilleengen (University of Surrey) In Person Only

The ongoing merger of the Milky Way and the Large Magellanic Cloud (LMC) is deforming the dark matter haloes of both galaxies, effectively making these galaxies a local dark matter collider. With stellar streams being sensitive to the gravitational potential, the Orphan-Chenab (OC) stream is particularly insightful as it spans the inner and outer Milky Way, and it passes close to the LMC. I will present the first models of the OC stream in time-dependent halos of the Milky Way and the LMC that are described by basis function expansions of N-body simulations of the Milky Way-LMC passage. I will show how these deformations have an observable signature on the OC stream. In particular, we find that the Milky Way’s dipole has the most significant effect. In order to determine which stellar streams best constrain these time-dependent haloes, I will present how to use information theory to probe the information content of the stream observables. This is a promising first step to using stellar streams as detectors in this dark matter collider to test the collisionless nature of dark matter.