FERMI LARGE AREA TELESCOPE DISCOVERY OF GeV GAMMA-RAY EMISSION FROM THE VICINITY OF SNR W44

Y. Uchiyama , S. Funk , H. Katagiri , J. Katsuta , M. Lemoine-Goumard (1) , H. Tajima , T. Tanaka , D. F. Torres

1 GLAST

We report the detection of GeV γ-ray emission from the molecular cloud complex that surrounds the supernova remnant (SNR) W44 using the Large Area Telescope on board Fermi. While the previously reported γ-ray emission from SNR W44 is likely to arise from the dense radio-emitting filaments within the remnant, the γ-ray emission that appears to come from the surrounding molecular cloud complex can be ascribed to the cosmic rays (CRs) that have escaped from W44. The non-detection of synchrotron radio emission associated with the molecular cloud complex suggests the decay of π0 mesons produced in hadronic collisions as the γ-ray emission mechanism. The total kinetic energy channeled into the escaping CRs is estimated to be Wesc ~ (0.3-3) × 1050 erg, in broad agreement with the conjecture that SNRs are the main sources of Galactic CRs.

Mots clés: acceleration of particles; cosmic rays; ISM: supernova remnants; radiation mechanisms: non-thermal

Domaines: Phénomènes cosmiques de haute energie [astro-ph.HE]; Phénomènes cosmiques de haute energie [astro-ph.HE]

Y. Uchiyama, S. Funk, H. Katagiri, J. Katsuta, M. Lemoine-Goumard, et al.. FERMI LARGE AREA TELESCOPE DISCOVERY OF GeV GAMMA-RAY EMISSION FROM THE VICINITY OF SNR W44. The Astrophysical journal letters, 2012, 749, pp.L35. ⟨10.1088/2041-8205/749/2/L35⟩. ⟨in2p3-00695269⟩