X-Ray Reflection Nebulae with Large Equivalent Widths of the Neutral Iron Kα Line in the Sagittarius C Region
Koyama, Katsuji; Nakajima, Hiroshi; Matsumoto, Hironori; Nobukawa, Masayoshi; Tsuru, Takeshi Go; Murakami, Hiroshi; Yamauchi, Shigeo; Senda, Atsushi
Japan
Abstract
This paper reports on the first results of a Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Kα from neutral or low-ionized Fe. One of them, M359.38-0.00, was newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M359.43-0.07 and M359.47-0.15, after subtracting the galactic center diffuse X-ray emission (GCDX), exhibit a strong Kα line from FeI with large equivalent widths (EWs) of 2.0--2.2keV and a clear Kβ of FeI. The GCDX in the Sgr C region is composed of the 6.4keV- and 6.7keV-associated components. These were phenomenologically decomposed by taking relations between the EWs of the 6.4keV and 6.7keV lines. Then, the former EWs against the associated continuum in bright clump regions were estimated to be 2.4+2.3-0.7keV. Since the two different approaches give similar large EWs of 2keV, we strongly suggest that the 6.4keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae).