Ground and Space-Based Telescopes

Examining the angular resolution of the ASTRO-H’s soft x-ray telescopes

[+] Author Affiliations
Toshiki Sato, Naomichi Kikuchi, Sho Kurashima, Nozomi Nakaniwa, Kazuki Tomikawa

Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan

Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, 229-8510, Japan

Ryo Iizuka

Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, 229-8510, Japan

Manabu Ishida, Yoshitomo Maeda

Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, 229-8510, Japan

Graduate University for Advanced Studies, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan

Takayuki Hayashi

NASA Goddard Space Flight Center, Code 662, Greenbelt, Maryland 20771, United States

Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan

Hideyuki Mori, Takashi Okajima, Peter J. Serlemitsos, Yang Soong

NASA Goddard Space Flight Center, Code 662, Greenbelt, Maryland 20771, United States

Takanori Izumiya

Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan

Sari Minami

Nara Women’s University, Kitauoyanishi-machi, Nara 630-8506, Japan

J. Astron. Telesc. Instrum. Syst. 2(4), 044001 (Oct 07, 2016). doi:10.1117/1.JATIS.2.4.044001
History: Received March 22, 2016; Accepted September 13, 2016
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Abstract.  The international x-ray observatory ASTRO-H was renamed “Hitomi” after launch. It covers a wide energy range from a few hundred eV to 600 keV. It is equipped with two soft x-ray telescopes (SXTs: SXT-I and SXT-S) for imaging the soft x-ray sky up to 12  keV, which focus an image onto the respective focal-plane detectors: CCD camera (SXI) and a calorimeter (SXS). The SXTs are fabricated in a quadrant unit. The angular resolution in half-power diameter (HPD) of each quadrant of the SXTs ranges between 1.1 and 1.4 arc min at 4.51 keV. It was also found that one quadrant has an energy dependence on the HPD. We examine the angular resolution with “spot scan” measurements. In order to understand the cause of imaging capability deterioration and to reflect it to the future telescope development, we carried out spot scan measurements, in which we illuminate all over the aperture of each quadrant with a square beam 8 mm on a side. Based on the scan results, we made “maps” of image blurring and a focus position. The former and the latter reflect figure error and positioning error, respectively, of the foils that are within the incident 8  mm×8  mm beam. As a result, we estimated those errors in a quadrant to be 0.9 to 1.0 and 0.6 to 0.9 arc min, respectively. We found that the larger the positioning error in a quadrant is, the larger its HPD is. The HPD map, which manifests the local image blurring, is very similar from quadrant to quadrant, but the map of the focus position is different from location to location in each telescope. It is also found that the difference in local performance causes energy dependence of the HPD.

© 2016 Society of Photo-Optical Instrumentation Engineers

Citation

Toshiki Sato ; Ryo Iizuka ; Manabu Ishida ; Naomichi Kikuchi ; Yoshitomo Maeda, et al.
"Examining the angular resolution of the ASTRO-H’s soft x-ray telescopes", J. Astron. Telesc. Instrum. Syst. 2(4), 044001 (Oct 07, 2016). ; http://dx.doi.org/10.1117/1.JATIS.2.4.044001


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