Suzaku Spectroscopy of an X-Ray Reflection Nebula anda New Supernova Remnant Candidate in the Sgr B1 Region

摘要

We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (1, b) = (0?5, —0?1) near to the Galacticcenter (GC) with the Suzaku/XIS. Emission lines of S xv, Fe I, Fe XXV, and Fe XXVI were clearly detected in thespectrum. We found that the Fe xxv and Fe XXVI line emissions smoothly distribute over the Sgr B 1 and B2 regionsconnecting from the GC. This result suggests that the GC hot plasma extends at least up to the Sgr B region withconstant 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 S xv Kα emission line, suggesting a candidate for a supernova remnantlocated in the GC region. The other one (M 0.51-0.10), having a prominent Fe I Ka emission line and a stronglyabsorbed continuum, is likely to be an X-ray reflection nebula. There is no near source bright enough to irradiateM 0.51-0.10. However, the FeI Kα emission can be explained if Sgr A~* was ~ 10~6times brighter 300 years ago,the light travel time for 100 pc to M 0.51-0.10, than it is at present.