American Association for the Advancement of Science, Science, 5956(326), p. 1080-1082, 2009
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Cosmic Acceleration Cosmic rays are thought to be accelerated in the shock waves produced by supernova explosions and can generate gamma rays when they interact with interstellar particles and radiation. Starburst galaxies, with their increased star formation rates, increased stellar explosion rates, and high densities of gas and radiation fields, are considered to be promising sources of gamma-ray emission. Using the High Energy Stereoscopic System (H.E.S.S) array of telescopes, Acero et al. (p. 1080 , published online 24 September) report the detection of gamma rays from one of the closest starburst galaxies, NGC 253. NGC 253 is a spiral galaxy, similar to our own Galaxy, except that its nucleus is undergoing an episode of intense star formation. The H.E.S.S. findings confirm that cosmic-ray acceleration is indeed efficient in starburst galaxies and open up new ways to understand cosmic-ray acceleration.