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.
Uncovering the nature of dark matter with stellar streams in the Milky Way
March 20, 2019
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.