Masaaki Sakano1, Robert S. Warwick1, Anne Decourchelle2
1 Department of Physics and Astronomy,
University of Leicester, Leicester LE1 7RH, UK
2 Service d'Astrophysique, CEA Saclay, L'Orme des merisiers, bat. 709, F-91191 Gif-sur-Yvette, France
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We present the X-ray study of the Sgr A region, particularly Sgr A East, with XMM-Newton, which provides the best-quality X-ray spectra ever obtained. The low- and high-energy band images show that hard X-rays are more concentrated on plane, except for the hard filamentary structure XMM J174540-2904.5. The spectrum of Sgr A East is represented with two-component thin thermal plasma model with temperatures of 1 and 4 keV, which has reached the ionization equilibrium state. The abundance of iron is found to be apparently higher in the central region up to a 3-4 solar value than in the outer area of 0.4-0.6 solar. On the other hand, the abundances of other elements are uniformly distributed with 1 solar. We also detected a weak fluorescent K-alpha line from neutral iron in the outer region. It is explained so that the dust shell surrounding Sgr A East is illuminated with Sgr A East itself. Combining the X-ray results of Sgr A East and Sgr A* with those of other wavelengths, we discuss the possible connection between them.