How precisely can neutrino emission from supernova remnants be constrained by gamma ray observations?

We propose a conceptually and computationally simple method to evaluate the neutrinos emitted by supernova remnants using the observed gamma ray spectrum. The proposed method does not require any preliminary parametrization of the gamma ray flux; the gamma ray data can be used as an input. In this way, we are able to propagate easily the observational errors and to understand how well the neutrino flux and the signal in neutrino telescopes can be constrained by gamma ray data. We discuss the various possible sources of theoretical and systematical uncertainties (e.g., hadronic modeling, neutrino oscillation parameters, etc.), obtaining an estimate of the accuracy of our calculation. Furthermore, we apply our approach to the supernova remnant RX J1713.7-3946, showing that neutrino emission is very well constrained by the H.E.S.S. gamma ray data: indeed, the accuracy of our prediction is limited by theoretical uncertainties. The observation of neutrinos from RX J1713.7-3946 seems possible with an exposure of the order of few km(2)xyear, provided that the detection threshold in future neutrino telescopes will be not higher than about 1 TeV.