The Arches Cluster and G0.1-0.1 cloud - A view with fluorescent lines

Abstract

We present the X-ray results on the Arches Cluster and G0.1-0.1 cloud obtained with XMM-Newton. In particular we have found a big loop-like annular structure, adjacent to the Arches Cluster, with the diameter of ∼3 arcmin (∼7 pc) and width of ∼1 arcmin (∼2 pc). The structure is found to show a non-thermal X-ray spectrum with a best-ftting photon index of Γ = 1.4 ± 0.6, together with a strong fiiorescent Kα line from neutral iron at 6.4-keV with an equivalent width of 1 keV. The G0.1-0.1 cloud shows a reasonable correlation among the 6.4-keV line, very hard continuum and 2.3-keV He-like sulphur line. We discuss the possible origin of these structures and further give a speculation to explain the origin of the fiiorescent X-ray lines in the Galactic Centre Region