Method to extract the primary cosmic ray spectrum from very high energy gamma-ray data and its application to SNR RX J1713.7-3946

摘要

Supernova remnants are likely to be the accelerators of the galactic cosmicrays. Assuming the correctness of this hypothesis, we develop a method toextract the parent cosmic ray spectrum from the VHE gamma ray flux emitted bysupernova remnants (and other gamma transparent sources). Namely, we calculatesemi-analytically the (inverse) operator which relates an arbitrary gamma rayflux to the parent cosmic ray spectrum, without relying on any theoreticalassumption about the shape of the cosmic ray and/or photon spectrum. Weillustrate the use of this technique by applying it to the young SNR RXJ1713.7-3946 which has been observed by H.E.S.S. experiment during the lastthree years. Specific implementations of the method permit to use as an inputeither the parameterized VHE gamma ray flux or directly the raw data. Thepossibility to detect features in the cosmic rays spectrum and the error in thedetermination of the parent cosmic ray spectrum are also discussed.