SPARTAN 1 X-ray observation of diffuse emission at the galactic center

Abstract

The 1–10 keV X-ray detectors on SPARTAN 1 scanned the central 2 degree region of the galactic center during 20–21 June 1985. Four strong point sources and extended emission ~1⁰ In diameter centered near the galactic center were detected [1]. We have re-analyzed the diffuse component data following the discovery [2] of Intense Fe line emission. The radial distribution of this component Is examined by grouping the data Into radial bins centered on Sgr A West, after first removing known point sources. We confirm that this component Is an Intense source of Fe line radiation, but find that the Fe line flux Is more sharply peaked and narrowly distributed than previously reported. A Gaussian surface brightness distribution with FWHM of 49-92 arcmln (90% confidence limits) Is consistent with the SPARTAN 1 data. The spectrum can be approximated with either a single power-law or thermal form, but the high χ² suggests a more complex shape. The radial distribution of the Fe line and continuum emission Is presented and used to address the nature of the diffuse component.