Recent X-ray studies have shown that supernova shock models are unable to satisfactorily explain X-ray emission in the rim of the Cygnus Loop. In an attempt to account for this anomalously enhanced X-ray flux, we fit the region with a model including theoretical charge exchange (CX) data along with shock and background X-ray models. The model includes the CX collisions of $O^{ 8+}$, $O{ 7+}$, $N^{ 7+}$, $N^{ 6+}$, $C^{ 6+}$, and $C^{ 5+}$ with H with an energy of 1 keV/u (438 km/s). The observations reveal a strong emission feature near 0.7 keV that cannot fully be accounted for by a shock model, nor the current CX data. Inclusion of CX, specifically $O^{ 7+} + H$, does provide for a statistically significant improvement over a pure shock model.
Categories: astro-ph.HE