Oral Presentation

The origin of the Galactic Ridge X-ray Emission

Takayuki Yuasa (RIKEN)

The origin of the apparently extended X-ray emission along the Galactic ridge has been a long-standing mystery of X-ray astronomy. A debate over two major ideas for explaining the emission origin, namely the dim-but-numerous point-source origin and the truly diffuse plasma origin, is getting to converge, mostly attributing the observed flux to the former. Chandra X-ray Observatory has been extensively used by Revnivtsev et al. 2009 to spatially resolve the dim point sources that comprise the extended emission, and we employed Suzaku X-ray Observatory's broad spectral coverage to spectroscopically decompose the emission into multiple source types (Yuasa et al. 2012). This talk will review the previous and recent studies on the Galactic ridge X-ray emission and reports detailed spectral calculations performed in our recent paper showing that the emission is composed, mainly, of coronally active stars and cataclysmic variables.