Can Charge Exchange Explain Anomalous Soft X-Ray Emission in the Cygnus Loop?
Abstract
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 O8 +, O7 +, N7 +, N6 +, C6 +, and C5 + with H with an energy of 1 keV u-1 (438 km s-1). 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 O7 + + H, does provide for a statistically significant improvement over a pure shock model.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2014
- DOI:
- 10.1088/2041-8205/787/2/L31
- arXiv:
- arXiv:1405.0939
- Bibcode:
- 2014ApJ...787L..31C
- Keywords:
-
- atomic processes;
- ISM: supernova remnants;
- line: formation;
- X-rays: general;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in ApJL, 5 pages, 4 figures, 1 table