Radio and X‐Ray Profiles in Supernova Remnants Undergoing Efficient Cosmic‐Ray Production

The strong shocks in young supernova remnants (SNRs) should accelerate cosmicrays (CRs) and no doubt exists that \rel electrons are produced in SNRs.However, direct and convincing evidence that SNRs produce CR nuclei has not yetbeen obtained and may, in fact, be long in coming if current gamma-rayobservatories do not see an unambiguous pion-decay feature. Nevertheless, thelack of an observed pion-decay feature does not necessarily mean that CR ionsare not abundantly produced since ions do not radiate efficiently. If CR ionsare produced efficiently by diffusive shock acceleration (DSA), their presencewill modify the hydrodynamics of the SNR and produce morphological effectswhich can be clearly seen in radiation produced by electrons. We describe insome detail our CR-hydro model, which couples DSA with the remnanthydrodynamics, and the synchrotron emission expected for two distinct parametersets representing type Ia and type II supernovae. Several morphologicalfeatures emerge in radial profiles, including the forward shock precursor,which are observable with current X-ray observatories and which shoulddefinitively show if young SNRs produce CR ions efficiently or not. For thespecific case of SN 1006, we conclude, as have others, that the extremely shortX-ray scale heights observed near the outer shock argue convincingly for theefficient production of CR ions.Comment: 20 pages, 13 figures, accepted in ApJ June 200