Speaker
Description
Outflows from star-forming regions are thought to have a profound effect on galaxy evolution. The role of cosmic rays in such outflows is however not clear at present. We report on the discovery of a cosmic-ray loaded outflow from the young massive star cluster Westerlund 1, which is known to accelerate cosmic rays to several tens of TeV. The outflow manifests itself as a ~150 pc-diameter GeV gamma-ray source in the direction of a low-density region in the interstellar medium at the edge of the Galactic disc. The GeV source is offset from the TeV gamma-ray emission surrounding the cluster, indicative of relativistic electrons that have escaped the cluster environment. Our results suggest the presence of cosmic-ray nuclei in the outflow, with a density far exceeding that in the average interstellar medium. We discuss possible implications of our work.
