We examine the impact of nonlinear diffusive shock acceleration on the TeV visibility of SNRs. A dense molecular cloud near a SNR provides a good target for pp-collisions leading to subsequent gamma ray emission through neutral pion decay. The intensity and the spectral shape of this radiation is thus determined by the spectrum of accelerated particles. This may become instrumental in distinguishing between the hadronic and leptonic origin of the emission.

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 2 (OG part 1), pages 763-766