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arXiv · astro-ph/0609308

Evidence for Solar-Wind Charge-Exchange X-Ray Emission from the Earth's Magnetosheath

Ryuichi Fujimoto·Kazuhisa Mitsuda·Dan McCammon·Yoh Takei·Michael Bauer·Yoshitaka Ishisaki·F. Scott Porter·Hiroya Yamaguchi·Kiyoshi Hayashida·Noriko Y. Yamasaki
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Abstract

We report an apparent detection of the C VI 4p to 1s transition line at 459 eV, during a long-term enhancement (LTE) in the Suzaku north ecliptic pole (NEP) observation of 2005 September 2. The observed intensity of the line is comparable to that of the C VI 2p to 1s line at 367 eV. This is strong evidence for the charge-exchange process. In addition to the C VI lines, emission lines from O VII, O VIII, Ne X, and Mg XI lines showed clear enhancements. There are also features in the 750 to 900 eV range that could be due to some combination of Fe XVII and XVIII L-lines, higher order transitions of O VIII (3p to 1s and 6p to 1s), and a Ne IX line. From the correlation of the X-ray intensity with solar-wind flux on time scales of about half a day, and from the short-term (~10 minutes) variations of the X-ray intensity, these lines most likely arise from solar-wind heavy ions interacting with neutral material in the Earth's magnetosheath. A hard power-law component is also necessary to explain the LTE spectrum. The origin of this component is not yet known. Our results indicate that solar activity can significantly contaminate Suzaku cosmic X-ray spectra below ~1 keV. Recommendations are provided for recognizing such contamination in observations of extended sources.

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Ryuichi Fujimoto, Kazuhisa Mitsuda, Dan McCammon, Yoh Takei, Michael Bauer, Yoshitaka Ishisaki, F. Scott Porter, Hiroya Yamaguchi, Kiyoshi Hayashida, Noriko Y. Yamasaki. 2006-09-12. Evidence for Solar-Wind Charge-Exchange X-Ray Emission from the Earth's Magnetosheath. https://doi.org/10.1143/ptps.169.71

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