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

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We report on the detection of a time variable O VII line emission in a deep 100ks 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 sr-1) to be emitted inside the heavily obscured galactic disk. It showed a factor of two time variation that showed a significant (∼4σ) correlation with the solar-wind O 7+ ion flux. The high line intensity and 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 while considering a line-of-sight direction and also theoretical distribution models of the neutral hydrogen and solar wind around Earth. Our results indicate that X-ray observations of geocoronal solar-wind charge-exchange emission can be used to constrain these models.

Original languageEnglish
Pages (from-to)981-986
Number of pages6
JournalPublications of the Astronomical Society of Japan
Volume62
Issue number4
DOIs
Publication statusPublished - 2010 Aug 25

Keywords

  • Earth
  • Sun: Solar wind
  • Sun: Solar-terrestrial relations
  • X-rays: Diffuse background

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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