Observations of the shell-type supernova remnant SN1006 have been carried out with the H.E.S.S .
system of Cherenkov telescopes during 2003 ( 18.2h with two operating telescopes ) and 2004 ( 6.3h with all four telescopes ) .
No evidence for TeV \gamma -ray emission from any compact or extended region associated with the remnant is seen and resulting upper limits at the 99.9 % confidence level are up to a factor 10 lower than previously-published fluxes from CANGAROO .
For SN1006 at its current epoch of evolution we give limits for a number of important global parameters .
Upper limits on the \gamma -ray luminosity ( for E =0.26 to 10 TeV , distance d =2 kpc ) of L _ { \gamma } < 1.7 \times 10 ^ { 33 } erg s ^ { -1 } , and the total energy in corresponding accelerated protons , W _ { p } < 1.6 \times 10 ^ { 50 } erg ( for proton energies E _ { p } \sim 1.5 to 60 TeV and assuming the lowest value n = 0.05 cm ^ { -3 } of the ambient target density discussed in literature ) are estimated .
Extending this estimate to cover the range of proton energies observed in the cosmic ray spectrum up to the knee ( we take here E _ { p } \sim 1 GeV to 3 PeV , assuming a differential particle index - 2 ) gives W _ { p } < 6.3 \times 10 ^ { 50 } erg .
A lower limit on the post-shock magnetic field of B > 25 \mu G results when considering the synchrotron/inverse-Compton framework for the observed X-ray flux and \gamma -ray upper limits .