0720047

The SNR RX J1713.7-3946 is part of a class of remnants dominated by synchrotron emission in X-rays and is one of the few detected at the TeV. It is therefore an excellent target to study particle acceleration at SNR shocks. The nature of the particles producing TeV emission is still a matter of controversy. The strong similarities between X-ray and TeV images suggest a leptonic origin but the required magnetic field is quite low. On the other hand to be viable hadronic scenarios require high ambient matter density at odds the the absence of strong thermal X-ray emission. The hard X-rays probe the electrons in the spectral cutoffs region and are therefore fundamental to understand the mechanisms of acceleration to the highest energies. Suzaku has been able to measure the integrated spectrum of the remnant but so far no detailed spectro-imagery exist for this object. We propose a 4Ms observation of RX J1713.7-3946 to map the hard X-ray emission from the remnant from 10 keV up to 50 keV and to resolve spatially the hard X-ray spectrum of the remnant. (we request a special 3x3 dithering mode allowing good JemX exposure while limiting systematics in the other instruments). This will allow a mapping of the spectral cutoffs in the shell and hopefully shed some light on the long standing problem of the origin of cosmic rays up to the knee. [truncated! Please see actual data for full text]