Direct evidence for hadronic cosmic-ray acceleration in the supernova remnant IC 443

M. Tavani, A. Giuliani, A.W. Chen, A. Argan, G. Barbiellini, A. Bulgarelli, P. Caraveo, P.W. Cattaneo, V. Cocco, T. Contessi, F. D'Ammando, E. Costa, G. De Paris, E. Del Monte, G. Di Cocco, I. Donnarumma, Y. Evangelista, A. Ferrari, M. Feroci, F. FuschinoM. Galli, F. Gianotti, C. Labanti, I. Lapshov, F. Lazzarotto, P. Lipari, F. Longo, M. Marisaldi, M. Mastropietro, S. Mereghetti, E. Morelli, E. Moretti, A. Morselli, L. Pacciani, A. Pellizzoni, F. Perotti, G. Piano, P. Picozza, M. Pilia, G. Pucella, M. Prest, M. Rapisarda, A. Rappoldi, E. Scalise, A. Rubini, S. Sabatini, E. Striani, P. Soffitta, M. Trifoglio, A. Trois, E. Vallazza, S. Vercellone, V. Vittorini, A. Zambra, D. Zanello, C. Pittori, F. Verrecchia, P. Santolamazza, P. Giommi, S. Colafrancesco, L.A. Antonelli, L. Salotti

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The supernova remnant (SNR) IC 443 is an intermediate-age remnant well known for its radio, optical, X-ray, and gamma-ray energy emissions. In this Letter, we study the gamma-ray emission above 100MeV from IC 443 as obtained by the AGILE satellite. A distinct pattern of diffuse emission in the energy range 100MeV-3GeV is detected across the SNR with its prominent maximum (source "A") localized in the northeastern shell with a flux F = (47±10) × 10?8photons cm?2s?1above 100MeV. This location is the site of the strongest shock interaction between the SNR blast wave and the dense circumstellar medium. Source "A" is not coincident with the TeV source located 0.4° away and associated with a dense molecular cloud complex in the SNR central region. From our observations, and from the lack of detectable diffuse TeV emission from its northeastern rim, we demonstrate that electrons cannot be the main emitters of gamma rays in the range 0.1-10GeV at the site of the strongest SNR shock. The intensity, spectral characteristics, and location of the most prominent gamma-ray emission together with the absence of cospatial detectable TeV emission are consistent only with a hadronic model of cosmic-ray acceleration in the SNR. A high-density molecular cloud (cloud "E") provides a remarkable "target" for nucleonic interactions of accelerated hadrons; our results show enhanced gamma-ray production near the molecular cloud/shocked shell interaction site. IC 443 provides the first unambiguous evidence of cosmic-ray acceleration by SNRs. © 2010. The American Astronomical Society. All rights reserved.
Original languageEnglish
Pages (from-to)-
JournalAstrophysical Journal Letters
Issue number2 PART 2
Publication statusPublished - 2010
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Tavani, M., Giuliani, A., Chen, A. W., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P., Cattaneo, P. W., Cocco, V., Contessi, T., D'Ammando, F., Costa, E., De Paris, G., Monte, E. D., Cocco, G. D., Donnarumma, I., Evangelista, Y., Ferrari, A., Feroci, M., ... Salotti, L. (2010). Direct evidence for hadronic cosmic-ray acceleration in the supernova remnant IC 443. Astrophysical Journal Letters, 710(2 PART 2), -.