Current status of the Astro-H X-ray Telescope system

Astro-H mission is the new Japanese X-ray mission following Suzaku. One of the unique features of the mission is an imaging spectroscopy in a unprecedentedly wide energy region from 0.3 to 60 keV. The X-Ray Telescope (XRT) system covers the energy region by means of grazing incidence reflective optics. In the current baseline specification, the XRT system consists of two hard X-ray telescopes (HXTs) which cover 5 to 60 keV, and two soft X-ray telescopes (SXT-S and SXT-I) which cover 0.3 to about 10 keV. Both of HXT and SXT-S mirrors employ tightly-nested, conicallyapproximated thin-foil Wolter-I optics. The HXTs employ Pt/C depth-graded multilayers (supermirrors), while the SXTS employ a single layer of gold. We measured test reflectors for Astro-H HXT at SPring-8, and obtained the roughness of the test reflectors of < 4 A and the image blur after two reflections of 0.8'-1.1'. International collaboration has been formed for the project, and basic and design studies have been carried out. Based on the basic study, detailed studies of the flight design are in progress, and production facilities for the Astro-H XRT system are close to complete.