X-ray Dust Scattering in the Direction of Galactic Centre

Abstract:

The Galactic Centre (GC) region contains many bright X-ray sources and has a high column density of foreground interstellar medium. This suggests that X-ray dust scattering should be ubiquitous and intensive in the GC direction. In my presentation, I will report our recent major progress in discovering various significant effects of dust scattering for GC X-ray sources. As an example, I will show that X-ray dust scattering can severely bias the observed spectrum of the GC LMXB AX J1745.6-2901 at 1.45 arcmin away from the Galactic SMBH Sgr A*, and explain its peculiar eclipse light curves. This study also allows us to put constraints on the GC foreground dust distribution, which indicate that most of the dust along the line-of-sight should reside in the Galactic disk rather than in the GC. I will also show that dust scattering halo is commonly observed around many GC sources, and so its spectral timing effects should be seriously considered for all these sources, including Sgr A*. Finally, I will introduce our Xspec models for the spectral correction of GC foreground dust scattering.