A Cocoon of Freshly Accelerated Cosmic Rays Detected by Fermi in the Cygnus Superbubble

Markus Ackermann , Marco Ajello , A. Allafort , Luca Baldini , Jean Ballet (1) , Guido Barbiellini , D. Bastieri , A. Belfiore , R. Bellazzini , B. Berenji , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , E. Bottacini , M. Brigida , Pascal Bruel (2) , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , J. M. Casandjian (1) , C. Cecchi , A. Chekhtman , C. C. Cheung , J. Chiang , S. Ciprini , R. Claus , J. Cohen-Tanugi (3) , A. de Angelis , F. de Palma , C. D. Dermer , E. Do Couto E Silva , P. S. Drell , D. Dumora (4) , C. Favuzzi , S. J. Fegan (2) , W. B. Focke , P. Fortin (2) , Y. Fukazawa , P. Fusco , F. Gargano , S. Germani , N. Giglietto , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , I. A. Grenier (1) , L. Guillemot , S. Guiriec , D. Hadasch , Y. Hanabata , A. K. Harding , M. Hayashida , K. Hayashi , E. Hays , G. Jóhannesson , A. S. Johnson , T. Kamae , H. Katagiri , J. Kataoka , M. Kerr , Jürgen Knödlseder (5) , M. Kuss , J. Lande , L. Latronico , S.-H. Lee , F. Longo , F. Loparco , B. Lott (4) , M. N. Lovellette , P. Lubrano , P. Martin , M. N. Mazziotta , J. E. Mcenery , J. Mehault (3) , P. F. Michelson , W. Mitthumsiri , T. Mizuno , C. Monte , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , M. Naumann-Godo (1) , P. L. Nolan , J. P. Norris , E. Nuss (3) , T. Ohsugi , A. Okumura , E. Orlando , J. F. Ormes , M. Ozaki , D. Paneque , D. Parent , M. Pesce-Rollins , M. Pierbattista (1) , F. Piron (3) , M. Pohl , D. Prokhorov , S. Rainò , R. Rando , M. Razzano , T. Reposeur (4) , S. Ritz , P. M. Saz Parkinson , C. Sgrò , E. J. Siskind , P. D. Smith , P. Spinelli , A. W. Strong (6) , H. Takahashi , T. Tanaka , J. G. Thayer , J. B. Thayer (1) , D. J. Thompson , L. Tibaldo , D. F. Torres , G. Tosti , A. Tramacere , E. Troja , Y. Uchiyama , J. Vandenbroucke , V. Vasileiou (3) , G. Vianello , V. Vitale , A. P. Waite , P. Wang , B. L. Winer , K. S. Wood , Z. Yang , S. Zimmer , Sylvain Bontemps (7)

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 LLR - Laboratoire Leprince-Ringuet
3 LUPM - Laboratoire Univers et Particules de Montpellier
4 GLAST
5 IRAP - Institut de recherche en astrophysique et planétologie
6 MPE - Max-Planck-Institut für Extraterrestrische Physik
7 FORMATION STELLAIRE 2011

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population.

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]; Astrophysique stellaire et solaire [astro-ph.SR]

Markus Ackermann, Marco Ajello, A. Allafort, Luca Baldini, Jean Ballet, et al.. A Cocoon of Freshly Accelerated Cosmic Rays Detected by Fermi in the Cygnus Superbubble. Science, 2011, 334, pp.1103-. ⟨10.1126/SCIENCE.1210311⟩. ⟨hal-00651320⟩