Azimuthal variation in the properties of cosmic ray acceleration at the blast wave of SN 1006

We present evidence for morphological changes due to efficient cosmic ray ion acceleration in the structure of the southeastern region of the supernova remnant SN 1006 using a combination of multi-wavelength observations. The forward shock front is clearly traced by a filament of Balmer emission in the southeast. This optical emission allows us to trace the location of the blast wave (BW) even where the synchrotron emission from relativistic electrons is either absent or too weak to detect. The contact discontinuity (CD) is traced using the low-energy X-ray (i.e., oxygen band) image which we argue reveals the distribution of shocked ejecta. We interpret the azimuthal variations of the ratio of radii between the BW and CD plus the X-ray and radio synchrotron emission at the BW using CR-modified hydrodynamic models. Different azimuthal profiles are assumed for the injection rate of particles into the acceleration process, magnetic field and level of turbulence. We found that the observations are consistent with a model in which these parameters are all azimuthally varying, being largest in the brightest regions. (author)