SN 1006 and cosmic-ray acceleration

SN 1006 is the prototype of supernova remnants in which the X-ray emission is dominated by synchrotron emission of cosmic-ray electrons. We have put together all XMM-Newton data on SN 1006 to get complete (but very inhomogeneous) coverage. We have also built a new radio map at comparable spatial resolution from VLA (interferometric) and Parkes (single dish) data. We show that the X-ray synchrotron emission is very peaked at the bright limbs (much more than the radio). This favors the geometry in which the bright limbs are polar caps, so that cosmic-rays would be accelerated preferentially where the magnetic field is parallel to the shock speed.