Uncovering the nature of dark matter with stellar streams in the Milky Way

Event Date: 
March 20, 2019
Ana Bonaca

Globular clusters are large congregations of stars, which gradually lose their members to form thin and long stellar streams. In pristine conditions, these streams have a nearly uniform density, however, new observations of one such structure in the Milky Way halo have revealed a likely site of perturbation. The on-sky morphology suggests a recent, close encounter with a massive and dense perturber. Known baryonic objects are unlikely perturbers based on their orbital properties, but observations permit a low-mass clump of dark matter as a plausible candidate. This discovery opens up the exciting possibility that detailed observations of streams could measure the abundance of dark-matter substructure and thus shed light on the nature of dark matter.

Speaker Bio: 
Ana Bonaca is a Fellow at the Institute for Theory and Computation, hosted by the Center for Astrophysics | Harvard & Smithsonian. She works on creating a 3D, high-resolution map of the Milky Way halo, which is dominated by the elusive dark matter. In her research, she collects and employs data from ground- and space-based observatories, analyzes numerical simulations and develops new statistical tools. Ana obtained an Astronomy PhD from Yale University and was awarded the Brouwer prize for a distinguished thesis.