Time Variability of the Geocoronal Solar Wind Charge Exchange in the Direction of the Celestial Equator

Yuichiro Ezoe; Ken Ebisawa; Noriko Y. Yamasaki; Kazuhisa Mitsuda; Hiroshi Yoshitake; Naoki Terada; Yoshizumi Miyoshi; Ryuichi Fujimoto

arXiv · 1006.5253

Time Variability of the Geocoronal Solar Wind Charge Exchange in the Direction of the Celestial Equator

Yuichiro Ezoe·Ken Ebisawa·Noriko Y. Yamasaki·Kazuhisa Mitsuda·Hiroshi Yoshitake·Naoki Terada·Yoshizumi Miyoshi·Ryuichi Fujimoto

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Abstract

We report the detection of a time variable OVII line emission in a deep 100 ks Suzaku X-ray Imaging Spectrometer spectrum of the Galactic Ridge X-ray emission. The observed line intensity is too strong (11+/-2 line unit or photon cm^-2 s^-1 str^-1) to be emitted inside the heavily obscured Galactic disk. It showed a factor of two time variation which shows a significant (~4 sigma) correlation with the solar wind O^7+ ion flux. The high line intensity and the good time correlation with the solar wind strongly suggests that it originated from geocoronal solar wind charge exchange emission. We discuss the X-ray line intensity considering a line of sight direction and also theoretical distribution models of the neutral hydrogen and solar wind around the Earth. Our results indicate that X-ray observationsof geocoronal solar wind charge exchange emission can be used to constrain these models.

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Yuichiro Ezoe, Ken Ebisawa, Noriko Y. Yamasaki, Kazuhisa Mitsuda, Hiroshi Yoshitake, Naoki Terada, Yoshizumi Miyoshi, Ryuichi Fujimoto. 2010-06-28. Time Variability of the Geocoronal Solar Wind Charge Exchange in the Direction of the Celestial Equator. https://arxiv.org/abs/1006.5253

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