Stellar Tidal Streams in Nearby Galaxies as Dark Matter Probes

Mergers and tidal interactions between massive galaxies and their dwarf satellites are a fundamental prediction of the Lambda-Cold Dark Matter cosmology. These events are thought to influence galaxy evolution throughout cosmic history and to provide important observational diagnostics of nonlinear structure formation. Thin stellar streams in the Milky Way and Andromeda galaxies are spectacular evidence for satellite disruption at the present day. However, constructing a statistically meaningful sample of tidal streams beyond our immediate cosmic neighborhood has proven a daunting observational challenge, and their potential for deepening our understanding of galaxy formation has yet to be realized. In this talk I present the results of the Stellar Tidal Stream Survey over the last decade, a project dedicated to the detection of stellar streams in the local Universe with robotic telescopes in collaboration with high-class astrophotographers. I will also discuss the perspectives to use stellar tidal streams as tracers of dark matter distribution around nearby spiral galaxies (including the Milky Way). In particular, narrow tidal streams could probe the existence of hundreds of dark matter halos without stars which could currently orbit the Milky Way, as predicted by recent cosmological simulations.

27/06/2019 - 12:30
Dr. David Martinez-Delgado
Instituto de Calculo Astronomico, Universidad de Heidelberg, Alemania