X-ray Emission from Charge Exchange in the Cygnus Loop SNR
arXiv:1502.05068 · doi:10.1093/mnras/stv319
Abstract
The Cygnus Loop has been the focus of substantial debate concerning the contribution of charge exchange (CX) to supernova remnant (SNR) X-ray emission. We take advantage of a distinct feature of CX, enhanced Kα forbidden line emission, and employ the energy centroid of the OVII Kα triplet as a diagnostic. Based on X-ray spectra extracted from an extensive set of Suzaku observations, we measure the energy centroid shifts of the triplet on and off the shock rim of the remnant. We find that enhanced forbidden to resonance line emission exists throughout much of the rim and this enhancement azimuthally correlates with non-radiative Hα filaments, a tracer of strong neutral-plasma interaction in the optical. We also show that alternative mechanisms cannot explain the enhancement observed. These results demonstrate the need to model the CX contribution to the X-ray emission of SNRs, particularly for shocks propagating in a partially neutral medium. Such modeling may be critically important to the correct measurements of the ionization, thermal, and chemical properties of SNRs.
8 pages, 5 figures, MNRAS accepted
References in corpus (6)
- Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
- Resolving the Origin of the Diffuse Soft X-ray Background
- EBIT Charge-Exchange Measurements and Astrophysical Applications
- Can Charge Exchange Explain Anomalous Soft X-ray Emission in the Cygnus Loop?
- Chandra Observations of the Northeastern Rim of the Cygnus Loop
- Inner-shell ionization, radiative losses and thermal conductivity in young SNRs