First peek of ASTRO-H Soft X-ray Telescope (SXT) in-orbit performance
First peek of ASTRO-H Soft X-ray Telescope (SXT) in-orbit performance
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首次展示 ASTRO-H 软 X 射线望远镜 (SXT) 在轨性能
DOI：
10.1117/12.2231705
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Takashi et al.
中科院分区：
文献类型：
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作者：
Okajima;Takashi et al.
ASTRO-H （Hitomi）是一颗日本x射线天体物理卫星，于2016年2月由JAXA的H-IIA运载火箭从日本种子岛发射升空。它有两个软x射线望远镜（sxt），以及其他仪器，是由美国宇航局戈达德太空飞行中心与ISAS/JAXA和名古屋大学合作开发的。一个用于x射线微量热仪（软x射线光谱仪，SXS），另一个用于x射线CCD相机（软x射线成像仪，SXI），两者都覆盖了高达15 keV的x射线能带。在ISAS/JAXA的30米x射线束线上对这两个sxt进行了全面表征。在1 keV和6 keV时，SXT+SXS组合系统的有效面积分别约为250和300 cm2，尽管观测时关闭了杜瓦口的闸阀，该闸阀阻挡了大部分低能x射线和一些高能x射线。SXS的角分辨率为1.2角分（半功率直径，HPD）。在1 keV和6 keV下，SXT+SXI组合系统的有效面积分别约为370和350 cm2。SXI的角分辨率为1.3角分（HPD）。这两个sxt的视场约为16角分（其渐晕功能的FWHM）。SXS阵列的大小限制了sst +SXS的视场为3 x 3 arcmin。在本次会议期间，SXT团队可获得的飞行数据有限，SXT+SXS无法获得点状源数据。虽然由于缺乏姿态信息，我们无法重建SXT+SXI的点扩展函数，但根据RXJ1856.5-3754数据，SXT在成像能力方面似乎如预期的那样工作。对于SXT+SXS和SXT+SXI的整体有效面积响应，螃蟹和G21.5-0.9数据的光谱模型拟合参数与之前的测量结果一致。另一方面，在这一点上，它们的2-10 keV通量相差约20%。校正工作仍在进行中。SXT是铝箔x射线镜的最新版本，它重量极轻，成本极低，但在宽波段内产生较大的有效面积。在ASTRO-H、钱德拉和xmm -牛顿望远镜中，它的面积质量比最大，为16平方厘米/千克。根据任务的科学目标，铝箔镜仍然是一项引人注目的技术。
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 cm2at 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 cm2at 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 x 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.