A connection between star formation activity and cosmic rays in the starburst galaxy M 82
Abstract
Although Galactic cosmic rays (protons and nuclei) are widely believed to be dominantly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery [1]. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size, more than 50 times the diameter of similar Galactic regions, uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density [2]. The cosmic rays produced in the formation, life, and death of their massive stars are expected to eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. M 82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in gamma rays [3, 4]. Here we report the detection of >700 GeV gamma rays from M 82. From these data we determine a cosmic-ray density of 250 eV cm-3 in the starburst core of M 82, or about 500 times the average Galactic density. This result strongly supports that cosmic-ray acceleration is tied to star formation activity, and that supernovae and massive-star winds are the dominant accelerators.
Cite
@article{arxiv.0911.0873,
title = {A connection between star formation activity and cosmic rays in the starburst galaxy M 82},
author = {V. A. Acciari and E. Aliu and T. Arlen and T. Aune and M. Bautista and M. Beilicke and W. Benbow and D. Boltuch and S. M. Bradbury and J. H. Buckley and V. Bugaev and K. Byrum and A. Cannon and O. Celik and A. Cesarini and Y. C. Chow and L. Ciupik and P. Cogan and P. Colin and W. Cui and R. Dickherber and C. Duke and S. J. Fegan and J. P. Finley and G. Finnegan and P. Fortin and L. Fortson and A. Furniss and N. Galante and D. Gall and K. Gibbs and G. H. Gillanders and S. Godambe and J. Grube and R. Guenette and G. Gyuk and D. Hanna and J. Holder and D. Horan and C. M. Hui and T. B. Humensky and A. Imran and P. Kaaret and N. Karlsson and M. Kertzman and D. Kieda and J. Kildea and A. Konopelko and H. Krawczynski and F. Krennrich and M. J. Lang and S. LeBohec and G. Maier and S. McArthur and A. McCann and M. McCutcheon and J. Millis and P. Moriarty and R. Mukherjee and T. Nagai and R. A. Ong and A. N. Otte and D. Pandel and J. S. Perkins and F. Pizlo and M. Pohl and J. Quinn and K. Ragan and L. C. Reyes and P. T. Reynolds and E. Roache and H. J. Rose and M. Schroedter and G. H. Sembroski and A. W. Smith and D. Steele and S. P. Swordy and M. Theiling and S. Thibadeau and A. Varlotta and V. V. Vassiliev and S. Vincent and R. G. Wagner and S. P. Wakely and J. E. Ward and T. C. Weekes and A. Weinstein and T. Weisgarber and D. A. Williams and S. Wissel and M. Wood and B. Zitzer},
journal= {arXiv preprint arXiv:0911.0873},
year = {2009}
}
Comments
18 pages, 4 figures; published in Nature; Version is prior to Nature's in-house style editing (differences are minimal)