X-Ray Spectrum of Sagittarius A East

Abstract

Abstract Sgr A East is a young SNR located in the Galactic Center (GC) region. Since the GC region is occupied by diffuse X-ray emission (GCDX) with a strong 6.7 keV line, an estimation of the GCDX is crucial to study the X-ray spectrum of Sgr A East. The flux and spectrum of the GCDX are found to be smoothly distributed around and across Sgr A East, and hence a reliable GCDX subtraction can be made. This paper presents the X-ray spectrum of Sgr A East with the XIS on board Suzaku. In addition to the previously reported $\mathrm{K}\alpha$ lines from S XV, Ar XVII, Ca XIX, and Fe XXV (all He-like atoms), we found $\mathrm{K}\alpha$ lines from S XVI, Ar XVIII, Fe XXVI (all hydrogenic atoms), and Ni XXVII (He-like), $\mathrm{K}\beta$ lines from S XV, Ar XVII, and Fe XXV, and a $\mathrm{K}\gamma$ line from Fe XXV. Plasma diagnostics using these lines revealed the presence of at least a two-temperature plasma. The overall spectrum can be fitted with a two-temperature ($\sim 1.2 \,\mathrm{keV}$ and $\sim 6 \,\mathrm{keV}$) plasma in ionization equilibrium plus a power-law component.