H.E.S.S. observations of the shell-type SNR RX J1713.7 3946

The shell-type supernova remnant (SNR) RX J1713.73946 (G347.3-0.5) was first discovered with ROSAT in X-rays [1] and later also observed to emit TeV γ-rays [2, 3]. This object, together with several other southern-hemisphere SNRs, is a prime target for observations with the High Energy Stereoscopic System (H.E.S.S.), a new system of imaging atmospheric Cherenkov telescopes which was completed at the end of 2003 in Namibia and is now in full operation [4, 5]. We present first results from deep observations of the SNR RX J1713.7 3946 conducted with the complete H.E.S.S. array in 2004. Almost all parts of the SNR emit gamma rays; the emission is found to resemble a shell structure with increased fluxes from the western and north-western part. The differential gamma-ray spectrum of the whole SNR extends over more than two orders of magnitude and appears rather hard with a power-law photon index of =2.27±0.02(stat.)±0.20(say.) The characteristics of the energy spectrum imply efcient acceleration of charged particles to energies well beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.