First peek of ASTRO-H Soft X-ray Telescope (SXT) in-orbit performance

Takashi Okajima, Yang Soong, Peter Serlemitsos, Hideyuki Mori, Larry Olsen, David Robinson, Richard Koenecke, Bill Chang, Devin Hahne, Ryo Iizuka, Manabu Ishida, Yoshitomo Maeda, Toshiki Sato, Naomichi Kikuchi, Sho Kurashima, Nozomi Nakaniwa, Takayuki Hayashi, Kazunori Ishibashi, Takuya Miyazawa, Kenji TachibanaKeisuke Tamura, Akihiro Furuzawa, Yuzuru Tawara, Satoshi Sugita

Research output: Chapter in Book/Report/Conference proceedingConference contribution

33 Citations (Scopus)


ASTRO-H (Hitomi) is a Japanese X-ray astrophysics satellite just launched in February, 2016, from Tanegashima, Japan by a JAXA's H-IIA launch vehicle. It has two Soft X-ray Telescopes (SXTs), among other instruments, that were developed by NASA's Goddard Space Flight Center in collaboration with ISAS/JAXA and Nagoya University. One is for an X-ray micro-calorimeter instrument (Soft X-ray Spectrometer, SXS) and the other for an X-ray CCD camera (Soft X-ray Imager, SXI), both covering the X-ray energy band up to 15 keV. The two SXTs were fully characterized at the 30-m X-ray beamline at ISAS/JAXA. The combined SXT+SXS system effective area is about 250 and 300 cm2 at 1 and 6 keV, respectively, although observations were performed with the gate valve at the dewar entrance closed, which blocks most of low energy X-rays and some of high energy ones. The angular resolution for SXS is 1.2 arcmin (Half Power Diameter, HPD). The combined SXT+SXI system effective area is about 370 and 350 cm2 at 1 and 6 keV, respectively. The angular resolution for SXI is 1.3 arcmin (HPD). The both SXTs have a field of view of about 16 arcmin (FWHM of their vignetting functions). The SXT+SXS field of view is limited to 3 × 3 arcmin by the SXS array size. In-flight data available to the SXT team was limited at the time of this conference and a point-like source data is not available for the SXT+SXS. Although due to lack of attitude information we were unable to reconstruct a point spread function of SXT+SXI, according to RXJ1856.5-3754 data, the SXT seems to be working as expected in terms of imaging capability. As for the overall effective area response for both SXT+SXS and SXT+SXI, consistent spectral model fitting parameters with the previous measurements were obtained for Crab and G21.5-0.9 data. On the other hand, their 2-10 keV fluxes differ by about 20% at this point. Calibration work is still under progress. The SXT is the latest version of the aluminum foil X-ray mirror, which is extremely light-weight and very low cost, yet produces large effective area over a wide energy-band. Its area-mass ratio is the largest, 16 cm2/kg, among ASTRO-H, Chandra, and XMM-Newton mirrors. The aluminum foil mirror is a still compelling technology depending on the mission science goal.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2016
Subtitle of host publicationUltraviolet to Gamma Ray
EditorsMarshall Bautz, Tadayuki Takahashi, Jan-Willem A. den Herder
ISBN (Electronic)9781510601895
Publication statusPublished - 2016
Externally publishedYes
EventSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray - Edinburgh, United Kingdom
Duration: 26-06-201601-07-2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
Country/TerritoryUnited Kingdom

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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