Detection of TeV gamma-ray emission from the shell-type supernova remnant RX J0852.0-4622 with HESS

We report the detection of TeV $\gamma$-rays from the shell-type supernova remnant RX J0852.0-4622 with data of 3.2 h of live time recorded with HESS in February 2004. An excess of ( $700 \pm 60$) events from the whole remnant with a significance of 12 $\sigma$ was found. The observed emission region is clearly extended with a radius of the order of $1\degr$ and the spatial distribution of the signal correlates with X-ray observations. The spectrum in the energy range between 500 GeV and 15 TeV is well described by a power law with a photon index of $\Gamma = 2.1 \pm 0.1_{{\rm stat}} \pm 0.2_{{\rm syst}}$ and a differential flux at 1 TeV of $\varphi_{1\,{\rm TeV}} = (2.1 \pm 0.2_{{\rm stat}} \pm 0.6_{{\rm syst}}) \times 10^{-11}~\mbox{cm}^{-2}\,\mbox{s}^{-1}\,\mbox{TeV}^{-1}$. The integral flux above 1 TeV was measured to be $\Phi(E>1\,\mbox{TeV}) = (1.9 \pm 0.3_{{\rm stat}} \pm 0.6_{{\rm syst}}) \times 10^{-11}~\mbox{cm}^{-2}\,\mbox{s}^{-1}$, which is at the level of the flux of the Crab nebula at these energies. More data are needed to draw firm conclusions on the magnetic field in the remnant and the type of the particle population creating the TeV $\gamma$-rays.