Suzaku Spectroscopy of an X-Ray Reflection Nebula and a New Supernova Remnant Candidate in the SgrB1 Region
Koyama, Katsuji; Nakajima, Hiroshi; Matsumoto, Hironori; Nobukawa, Masayoshi; Tsuru, Takeshi Go; Murakami, Hiroshi; Yamauchi, Shigeo; Hyodo, Yoshiaki; Inui, Tatsuya; Takikawa, Yojiro
Japan
Abstract
We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) = (0°.5, -0°.1) near to the Galactic center (GC) with the Suzaku/XIS. Emission lines of SXV, FeI, FeXXV, and FeXXVI were clearly detected in the spectrum. We found that the FeXXV and FeXXVI line emissions smoothly distribute over the SgrB1 and B2 regions connecting from the GC. This result suggests that the GC hot plasma extends at least up to the SgrB region with constant temperature. There are two diffuse X-ray sources in the observed region. One of the two (G0.42-0.04) is newly discovered, and exhibits a strong SXV Kα emission line, suggesting a candidate for a supernova remnant located in the GC region. The other one (M0.51-0.10), having a prominent FeI Kα emission line and a strongly absorbed continuum, is likely to be an X-ray reflection nebula. There is no near source bright enough to irradiate M0.51-0.10. However, the FeI Kα emission can be explained if SgrA* was ∼ 106 times brighter 300years ago, the light travel time for 100 pc to M0.51-0.10, than it is at present.