X-ray emission due to charge exchange between solar wind and earth atmosphere on September 12, 2005

A sky region close to the supernova remnant SN1006 was observed twice with Suzaku on September 12, 2005, and on January 26, 2006. We found that the region was bright in a soft X-ray band during the first observation. Comparing the XIS spectra of the two observations, we found that the soft X-ray brightening can be explained by emission lines from ionized carbon, nitrogen, oxygen, iron, and so on. Emission lines due to the transitions from the M shell or higher to the K shell were included. These characteristics strongly suggest that the origin of the soft X-ray brightening is the charge exchange between solar wind ions and neutral atoms in the Earth atmosphere.