The Thin X-ray Rims of SN1006

The historical supernova remnant SN 1006 AD and several other young supernova remnants (SNRs) display sharp X-ray synchrotron rims along their edges. These rims are very narrow, requiring the abrupt disappearance of either relativistic electrons or magnetic field downstream. If synchrotron losses on electrons are responsible, magnetic fields must be amplified by orders of magnitude in the shock. We present new Chandra observations of SN 1006, including the first long exposure of the southwest limb, and measure the filament widths in the ranges 0.5 to 1, 1 to 2, and 2 to 7 keV. We interpret them with three theoretical models: synchrotron losses on diffusing or on convecting electrons, or damping of temporary magnetic turbulence. Differentiating among these models is important, as post-shock magnetic field amplification has direct implications for the possibility of SNRs accelerating cosmic rays up to the “knee” in the integrated cosmic-ray spectrum around 3000 TeV. To do this, we primarily consider the energy dependence of filament widths in the 0.5-7 keV band. For all three models, we also derive estimates of the post-shock magnetic field through both simple approximations and full numerical calculations. We find that profiles at a specific energy can be well fit by any of the three models, but the approximate scaling of the widths with energy ( E_-.2 to E_-.5) requires a hybrid model. We also confirm that significant magnetic-field amplification is required for all models, with average post-shock estimates ranging from ~ 70 μG -120 μG in the northeast and ~ 60 μG-110 μG in the southwest. This work is supported by NASA through grant GO2-13066A.