伊藤 真之 | ![]() |
イトウ マサユキ | |
大学院人間発達環境学研究科 人間環境学専攻 | |
教授 | |
物理学関係 |
研究論文(国際会議プロシーディングス)
研究論文(研究会,シンポジウム資料等)
研究論文(大学,研究機関等紀要)
科学技術振興機構次世代人材育成事業の一環であるグローバルサイエンスキャンパスの支援(2017-2020年度)を受けて,神戸大学,兵庫県立大学,関西学院大学,甲南大学が共同で企画・実施する教育プログラムについて紹介する.プログラムの正式名称は「根源を問い革新を生む国際的科学技術人材育成挑戦プログラム」で,略称をROOTプログラムとしている.強い好奇心・探求心を備えた高校生等を公募,毎年40名程度を選抜し,約半年間の基礎ステージと,その中から選抜された8名程度を対象とした実践ステージを通じて,(a) 根源に迫る課題設定能力,(b) 高度な科学的探究力,(c) 価値の知的検討能力,(d) 国際コミュニケーション力を備えた人材を育成することを目指す.この教育プログラムでは,受講生自らが研究課題を設定し研究計画を立案する能力を実践的に身に着けることを重視している.
一般社団法人 日本科学教育学会, 2019年08月, 日本科学教育学会年会論文集, 43 (0), 399 - 400, 日本語研究論文(研究会,シンポジウム資料等)
This study investigates how different segments of the public, with varying degrees of interest in S&T, could formulate opinions on a broader vision and the role they think STI should play in Japanese society through 2020 (Tokyo's Olympic and Paralympic year) and toward 2030. We conducted nine inclusive public engagement activities. Results indicated that the broad public opinions did not completely overlap with officials' opinions, a value of “open and appropriate” was mainly found from the unengaged public, and the visions and values based on their opinions could well be incorporated into the official document. Engaging the disinterested in S&T remains an issue.
Sissa Medialab, 2019年06月14日, Journal of Science Communication, 18 (03), A02, 英語[査読有り]
研究論文(学術雑誌)
2017 年度より神戸大学は、兵庫県立大学、関西学院大学、甲南大学と ROOT と名付けたグローバルサイエンスキャンパス事業に取り組んでいる。そのプログラムでは強い知的好奇心と探究心を備えた高校生に根源的な問を喚起するユニットをはじめとする「科学力養成プログラム」と科学英語を学ばせる「国際性導入プログラム」を基礎ステージで高校生に提供し、その中から選抜された高校生に実践ステージで大学教員が研究指導を行い、ワ
シントン大学でポスター発表させる。2017 年度 ROOT プログラムに参加した 45 名の高校生を対象にインタビュー、ルーブリック評価、レジリエンス尺度、質問紙調査を用いて到達度、満足度などを調べた。その結果、基礎ステージで大半の受講生が満足できる水準に到達していること、実践ステージで 3 つのカテゴリーで有意な上昇をしていることが確かめられた
[査読有り]
研究論文(大学,研究機関等紀要)
研究論文(大学,研究機関等紀要)
© The Authors. The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.
SPIE, 2018年04月, Journal of Astronomical Telescopes, Instruments, and Systems, 4 (2), 021402, 英語研究論文(国際会議プロシーディングス)
研究論文(学術雑誌)
© 2018 The Authors. We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline. The angular resolution defined by a half-power diameter was 1.9′ (HXT-1) and 2.1′ (HXT-2) at 8 keV, 1.9′ at 30 keV, and 1.8′ at 50 keV. The effective area was found to be 620cm2 at 8 keV, 178cm2 at 30 keV, and 82cm2 at 50 keV per mirror module. Although the angular resolutions were slightly worse than the requirement (1.7′), the effective areas sufficiently exceeded the requirements of 150cm2 at 30 keV and 55cm2 at 50 keV. The off-axis measurements of the effective areas resulted in the field of view being 6.1′ at 50 keV, 7.7′ at 30 keV, and 9.7′ at 8 keV in diameter. We confirmed that the main component of the stray x-ray light was significantly reduced by mounting the precollimator as designed. Detailed analysis of the data revealed that the angular resolution was degraded mainly by figure errors of mirror foils, and the angular resolution is completely explained by the figure errors, positioning errors of the foils, and conical approximation of the foil shape. We found that the effective areas were ∼80% of the designed values below 40 keV, whereas they steeply decline above 40 keV and become only ∼50%. We investigated this abrupt decline and found that neither the error of the multilayer design nor the errors of the incident angles induced by the positioning errors of the foils can be the cause. The reflection profile of each foil pair from the defocused image strongly suggests that the figure errors of the foils probably bring about the reduction in the effective areas at higher energies.
The International Society for Optical Engineering, 2018年01月01日, Journal of Astronomical Telescopes, Instruments, and Systems, 4 (1), 011210, 英語研究論文(学術雑誌)
兵庫県西部を流れる千種川は清流として知られる一方, しばしば大雨による河川氾濫が発生している. 2016年まで, 災害防止の目的で河川整備工事が行われたが, 工事による河川環境の変化や河川生態系への影響が懸念されている. 本研究では千種川の水循環や人為改変の環境影響評価の研究に必要な基礎データを得ることを目的として, 2015年8月9日に採取された河川水試料83点について, 水の水素・酸素同位体比を分析した.分析の結果は地理情報システム(GIS)により流域地図にマッピングした. 結果として, 千種川流域では, 水素・酸素同位体比ともに上流部で低い値を示し, 主要支流の佐用川や, 千種川下流に流入する支流では高い値を示した. また, 上流~中流では高度効果の影響を受けた降水の寄与がみられており, 千種川流域全体で蒸発の影響が大きいことが推測される.
神戸大学大学院人間発達環境学研究科, 2017年09月, 神戸大学大学院人間発達環境学研究科紀要, 11 (1), 105 - 109, 日本語[査読有り]
研究論文(大学,研究機関等紀要)
X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E approximate to 3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of S XVI (E similar or equal to 3.44 keV rest-frame)-a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment.
IOP PUBLISHING LTD, 2017年03月, ASTROPHYSICAL JOURNAL LETTERS, 837 (1), L15 - L23, 英語[査読有り]
研究論文(学術雑誌)
Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes(1) of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling-a process known as active galactic nucleus feedback(2-6). Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 +/- 10 kilometres per second in the region 30-60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 +/- 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure.
NATURE PUBLISHING GROUP, 2016年07月, NATURE, 535 (7610), 117 - +, 英語[査読有り]
研究論文(学術雑誌)
平成27年度日本科学教育学会第7回研究会(四国支部開催); [日時] 平成28年5月28日(土); [会場]香川大学; [主催]一般社団法人日本科学教育学会
日本科学教育学会, 2016年05月, 日本科学教育学会研究会研究報告, 30 (7), 17 - 20, 日本語研究論文(研究会,シンポジウム資料等)
平成27年度日本科学教育学会第7回研究会(四国支部開催); [日時] 平成28年5月28日(土); [会場]香川大学; [主催]一般社団法人日本科学教育学会
日本科学教育学会, 2016年05月, 日本科学教育学会研究会研究報告, 30 (7), 21 - 24, 日本語研究論文(研究会,シンポジウム資料等)
© 2016 SPIE. The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.
SPIE, 2016年, Proceedings of SPIE - The International Society for Optical Engineering, 9905, 英語研究論文(国際会議プロシーディングス)
© 2016 SPIE. A ray-trace simulation code for the Hard X-ray Telescope (HXT) on board the Hitomi (ASTRO-H) satellite is being developed. The half power diameter and effective area simulated based on the code are consistent with ground measurements within 10%. The HXT observed the pulsar wind nebula G21.5-0.9 for 105 ksec. We confirmed that the encircled energy function and the half power diameter obtained from the data are consistent with the ground measurements.
SPIE, 2016年, Proceedings of SPIE - The International Society for Optical Engineering, 9905, 英語研究論文(国際会議プロシーディングス)
© 2016 SPIE. The Japanese X-ray Astronomy Satellite, Hitomi (ASTRO-H) carries hard X-ray imaging system, covering the energy band from 5 keV to 80 keV. The hard X-ray imaging system consists of two hard X-ray telescopes (HXT) and the focal plane detectors (HXI). The HXT employs tightly-nested, conically-approximated thin foil Wolter-I optics. The mirror surfaces of HXT were coated with Pt/C depth-graded multilayers. We carried out ground calibrations of HXTs at the synchrotron radiation facility SPring-8/BL20B2 Japan, and found that total effective area of two HXTs was about 350 cm2 at 30 keV, and the half power diameter of HXT was about 1.'9. After the launch of Hitomi, Hitomi observed several targets during the initial functional verification of the onboard instruments. The Hitomi software and calibration team (SCT) provided the Hitomi's data of G21.5-0.9, a pulsar wind nebula, to the hardware team for the purpose of the instrument calibration. Through the analysis of the in-flight data, we have confirmed that the X-ray performance of HXTs in orbit was consistent with that obtained by the ground calibrations.
SPIE, 2016年, Proceedings of SPIE - The International Society for Optical Engineering, 9905, 英語研究論文(国際会議プロシーディングス)
月周回探査衛星SELENE に搭載されたα線検出器(ARD : Alpha-Ray Detector)は月面から放出されるRn-222 およびその崩壊過程で生じるPo-210 から放射されるα線を観測し,月表層下のウラニウムの分布および断層などの地殻構造,月の希薄大気の動態等に関する情報を得ることを目的とする.本論文では,ARD のデータ処理の流れと,角度応答関数を考慮した月面のα線強度分布の導出方法について紹介する.この方法は月ラドンα線観測データの解析では始めて用いられるもので,α線強度分布マップの解像度を向上し,月地形等の詳細な比較を可能とする.
宇宙航空研究開発機構, 2015年03月, 宇宙航空研究開発機構研究開発報告: 宇宙科学情報解析論文誌, 4, 151 - 160, 日本語[査読有り]
研究論文(学術雑誌)
月周回探査衛星SELENEに搭載されたα線検出器(ARD : Alpha-Ray Detector)は月面から放出される222Rnおよびその崩壊過程で生じる210Poから放射されるα線を観測し,月表層下のウラニウムの分布および断層などの地殻構造,月の希薄大気の動態等に関する情報を得ることを目的とする.本論文では,ARDのデータ処理の流れと,角度応答関数を考慮した月面のα線強度分布の導出方法について紹介する.この方法は月ラドンα線観測データの解析では始めて用いられるもので,α線強度分布マップの解像度を向上し,月地形等の詳細な比較を可能とする.
宇宙航空研究開発機構, 2015年03月, 宇宙科学情報解析論文誌, 14 (4), 151 - 160, 日本語[査読有り]
研究論文(大学,研究機関等紀要)
日本の中学校・高等学校における宇宙教育の現状について把握することを目的として,全国の中学校・高等学校の理科教師を対象にアンケート調査を行った。その結果,中学校・高等学校共に,教師は,生徒の関心が宇宙全般及び天文分野では高いと考えているが,技術分野の関心は高いとは考えていないということや,中学校の教師は授業時間は充分であると考えているが,高等学校の教師は不足していると考えていること,希望するサービスは,双方共に,実用的な教材・資料や専門家の出前授業,教師対象の研修会などであることが分かった。これらの一部に関してはJAXAなどによる既存のサービスがあり,ポータルサイトの開設などを通じてそれらの認知を高める取り組みが有意義であると考えられる。
日本科学教育学会, 2014年12月, 日本科学教育学会研究会研究報告, 29 (3), 51 - 54, 日本語研究論文(研究会,シンポジウム資料等)
The new Japanese x-ray astronomy satellite, ASTRO-H, will carry two identical hard x-ray telescopes (HXTs), which cover the energy range of 5 to 80 keV. The HXT mirrors employ tightly nested, conically approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance the hard x-ray effective area by means of Bragg reflection. The HXT comprises foils 120-450 mm in diameter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The requirements for HXT are a total effective area of >300 cm<sup>2</sup> at 30 keV and an angular resolution of <1.7<sup>'</sup> in half-power diameter (HPD). Fabrication of two HXTs has been completed, and the x-ray performance of each HXT was measured at a synchrotron radiation facility, SPring-8 BL20B2 in Japan. Angular resolutions (HPD) of 1.9<sup>'</sup> and 1.8<sup>'</sup>at 30 keV were obtained for the full telescopes of HXT-1 and HXT-2, respectively. The total effective area of the two HXTs at 30 keV is 349 cm<sup>2</sup>.
2014年11月10日, Applied optics, 53 (32), 7664 - 7676[査読有り]
研究論文(学術雑誌)
日本の中学校における宇宙教育の現状について把握することを目的として,中学校理科教員を対象にアンケート調査を行った。その結果,中学校教員は宇宙に関する教科書の内容や授業時間に不満はなく,教科書以外の資料を積極的に授業に取り入れている一方で,野外学習など体験授業はあまり行われていないこと,教員自身の知識不足などを課題と感じていることなどが明らかとなった。今後希望するサービスとして,実用的な教材・資料や専門家の出前授業,教員対象の研修会などが挙げられた。これらの一部に関してはJAXA などによる既存のサービスがあり,ポータルサイトの開設などを通じてそれらの認知を高める取り組みが有意義であると考えられる。
日本科学教育学会, 2014年09月, 日本科学教育学会年会論文集, (38), 547 - 548, 日本語研究論文(研究会,シンポジウム資料等)
[査読有り]
研究論文(学術雑誌)
© 2014 SPIE.The new Japanese X-ray Astronomy satellite, ASTRO-H will carry two identical hard X-ray telescopes (HXTs), which cover 5 to 80 keV, in order to provide new insights into frontier of X-ray astronomy. The HXT mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area by means of Bragg reflection, and 213 mirror reflectors with a thickness of 0.22 mm are tightly nested confocally in a telescope. The production of FM HXT-1 and HXT-2 were completed in 2012 and 2013, respectively. The X-ray performance of HXTs were measured at the synchrotron radiation facility SPring-8/ BL20B2 Japan. The total effective area of two HXTs is about 350 cm2 at 30 keV and the angular resolution of HXT is about 1.'9 in half power diameter at 30 keV. The HXTs are in the clean room at ISAS for waiting the final integration test.
2014年, Proceedings of SPIE - The International Society for Optical Engineering, 9144[査読有り]
研究論文(国際会議プロシーディングス)
神戸大学サイエンスショップは,科学・技術に関わる市民のエンパワーメントを目指し,市民の科学活動への支援等に取り組んでいる。その活動等の中から,フォーマル/ノンフォーマルの枠を超えた科学の教育,学びなどの取組み事例とそこから得られる示唆を紹介する。主な論点は以下のとおりである。(1)サイエンスカフェが広がりを見せており,ノンフォーマル/インフォーマルな学びの場として機能している。(2)南あわじ市では,科学コミュニケーションが,地域課題の解決や将来ビジョン策定に活かされる成果を収めた。(3)サイエンスショップは,中等教育における探求活動の支援にも取組む。今後,成人層の研究活動の展開を促したい。
日本科学教育学会, 2012年08月, 日本科学教育学会年会論文集, 36, 171 - 174, 日本語研究論文(研究会,シンポジウム資料等)
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-Throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ?E 5 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes. © 2012 SPIE.
SPIE, 2012年, Proceedings of SPIE - The International Society for Optical Engineering, 8443, 84431Z - 84431Z-22, 英語研究論文(国際会議プロシーディングス)
A "formation flight astronomical survey telescope" (FFAST) is a new project that will cover a large sky area in hard X-ray. In particular, it will focus on the energy range up to 80 keV. It consists of two small satellites that will go in a formation flight. One is an X-ray telescope satellite carrying a "super mirror" and the other is a detector satellite carrying an SDCCD. Two satellites are put into a low earth orbit. They are in a formation flight with a separation of 20m. Since two satellites are put into Keplerian orbit, the observation direction is moving the sky rather than pointing to a fixed direction. This project will survey a large sky area at hard X-ray region to study the evolution of the universe
SPIE-INT SOC OPTICAL ENGINEERING, 2012年, SPACE TELESCOPES AND INSTRUMENTATION 2012: ULTRAVIOLET TO GAMMA RAY, 8443, 英語研究論文(国際会議プロシーディングス)
ASTRO-H is an international X-ray mission of ISAS/JAXA, which will be launched in 2014. One of the main characteristics of ASTRO-H is imaging spectroscopy in the hard X-ray band above 10 keV. ASTRO-H will carry two identical Hard X-ray telescopes (HXTs), whose mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area up to 80 keV. HXT was designed based on the telescope on board the SUMIT balloon borne experiment. After feasibility study of the HXT design, the FM design has been deteremined. Mass production of the mirror shells at Nagoya University has been going on since August 2010, and production of mirror shells for HXT-1 was completed in March 2012. After the integation of X-ray mirrors for HXT-1, we measured hard X-ray performance of selected mirror shells for HXT-1 at a synchrotron radiation facility, SPring-8 beamline BL20B2. We will perform environment tests and ground calibarations at SPring-8 for HXT-1. In HXT-2, foil production is going on. © 2012 SPIE.
SPIE, 2012年, Proceedings of SPIE - The International Society for Optical Engineering, 8443, 英語研究論文(国際会議プロシーディングス)
研究論文(学術雑誌)
We are planning to have a "formation flight all sky telescope" (FFAST) that will cover a large fraction of the whole sky area in relatively high energy X-ray. In particular, it will focus on the energy range above 10 keV. It consists of two small satellites that will go in a formation flight. One is the X-ray telescope satellite and the other is the detector satellite. Two satellites will be simultaneously launched by a single rocket vehicle into a low earth orbit. They are in a formation flight with a separation of 20 m ± 10 cm. The observation direction is determined by the two satellites. Since two satellites are put into the Keplerian orbit, the observation direction is scanning the sky rather than pointing to a fixed direction. One satellite carries an X-ray telescope covering the energy range up to 80 keV. The telescope is a "super-mirror" that has a multi-layer coating to collect X-rays up to 80 keV. The other is a detector satellite that carries an SDCCD system. The SDCCD consists of a fully depleted CCD and a scintillator so that we can obtain the image up to 80 keV.
THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2010年, Transactions of the Japanese Society for Artificial Intelligence, Volume 8, pp. To_4_7-To_4_12 (27), To_4_7 - To_4_12, 英語研究論文(学術雑誌)
The new Japanese X-ray Astronomy satellite, ASTRO-H will carry two identical hard X-ray telescopes (HXTs), which cover 5 to 80 keV. The HXT mirrors employ tightly-nested, conically-approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area by means of Bragg reflection. The HXT comprises foils 450 mm in diamter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The effective area is expected to be ∼ 310 cm2 at 30 keV and the image quality to be ∼1.7′ in half-power diameter. © 2010 SPIE.
2010年, Proceedings of SPIE - The International Society for Optical Engineering, 7732, 英語研究論文(国際会議プロシーディングス)
We report on Suzaku observations of SN 1987 A in the Large Magellanic Cloud, performed in 2005 November and 2006 June. The observations provide medium resolution X-ray spectra during the phase of the interaction between the supernova blast wave and the inner circumstellar ring. The Suzaku observations complement XMM-Newton and Chandra observations and were used to investigate the spectral evolution of SN 1987 A. The spectra were analyzed with two-temperature emission model from shocked gas. For the flux in the soft band (0.5-2.0 keV) we obtained 25.7(-1.9)(+1.4) x 10(-13) erg cm(-2) (2005) and 30.8(-1.7)(+1.4) x 10(-13) erg cm(-2) (2006). The exponential rise seen in the soft X-ray light curve of SN 1987 A till similar to 6500 d after the explosion slowed down significantly between the Suzaku observations. Recent Chandra and XMM-Newton observations confirm this evolution. SN 1987 A continues to brighten exponentially, but with longer characteristic timescale. This must be caused by a less rapidly increasing emission measure.
OXFORD UNIV PRESS, 2009年08月, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 61 (4), 895 - 899, 英語[査読有り]
研究論文(学術雑誌)
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 Ȧ 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.© 2009 SPIE.
2009年, Proceedings of SPIE - The International Society for Optical Engineering, 7437, 英語研究論文(国際会議プロシーディングス)
Purpose - The purpose of this paper is to introduce the Regional Centre of Expertise (RCE) on education for sustainable development (ESD) Hyogo-Kobe, and the contribution of Kobe University as a model case. An attempt to develop and implement a new ESD programme in higher education is also reported. Design/methodology/approach - A brief description of RCE Hyogo-Kobe, which was approved in 2007, is followed by the description of the contribution of Kobe University to the RCE's starting phase to date and in the near future. The initiative of establishing the RCE as well as the design and implementation of the ESD programme developed through the collaboration of three faculties: the Faculty of Human Development, the Faculty of Letters, and the Faculty of Economics. The programme focuses on students carrying out participatory action research enabled by collaboration with regional stakeholders on ESD and SD. Findings - Interdisciplinary collaboration was found to be essential in creating an innovative education programme in higher education. Activities and projects on ESD that existed earlier played important roles in the initiative, in formation of the network, and in directing RCE activities. Originality/value - Information from the case study will be useful in the establishment and development of an RCE through the initiative of an institute of higher education. © Emerald Group Publishing Limited.
2008年, International Journal of Sustainability in Higher Education, 9 (4), 479 - 486, 英語[査読有り]
研究論文(学術雑誌)
We are planning to have a "formation flight all sky telescope" (FFAST) that will cover a large sky area in relatively high energy X-ray. In particular, it will focus on the energy range above 10 keV. It consists of two small satellites that will go in a formation flight. One is an X-ray telescope satellite and the other is a detector satellite. Two satellites will be simultaneously launched by a single rocket vehicle into a low earth orbit. They are in a formation flight with a separation of 20m +/- 10cm. The observation direction is determined by the two satellites. Since two satellites are put into Keplerian orbit, the observation direction is scanning the sky rather than pointing to a. fixed direction. The X-ray telescope satellite carries one super-mirror covering the energy range up to 80 keV. The telescope is 45-cm diameter and its focal length is 20m. The telescope is a "super mirror" that has a multi-layer coating covering the energy range tip to 80 keV. The effective area is about 500 cm(2) at low energy and 200 cm(2) at 70 keV. The mirror system is a thin foil mirror that is developing at Nagoya University that is being developed. The PSF of the mirror will be about 1-2 arcmin. The satellite is equipped with an attitude control system using momentum wheel. It will keep the satellite such that the optical axis of the mirror is pointing to the detector satellite. The other is a detector satellite that carries an SDCCD system. The SDCCD is a CCD with a scintillator that is directly attached to the CCD. The CCD chip is fully depleted which can be a back-illuminated CCD. The scintillator is attached to the CCD at back side so that it has high detection efficiency for visible photons generated inside the scintillator. The X-ray enters into the CCD at front side. Therefore, low energy X-rays (below 10keV) can be photo-absorbed in the depletion layer of the CCD while high energy X-rays will be absorbed in the scintillator that will emit visible photons The visible photons can be detected by the CCD. Depletion layer events usually form small charge spread while scintillator events usually form large charge spread. These events generate charge spread in a symmetric form with different size. On the contrary, charged particles leave an elongated charge spread that can be distinguished from X-ray events by pattern recognition. This project, Formation Flight All Sky Telescope (FFAST), will scan a large sky area at hard X-ray region.
SPIE-INT SOC OPTICAL ENGINEERING, 2008年, SPACE TELESCOPES AND INSTRUMENTATION 2008: ULTRAVIOLET TO GAMMA RAY, PTS 1 AND 2, 7011, 英語研究論文(国際会議プロシーディングス)
High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.
OXFORD UNIV PRESS, 2007年01月, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 59, S1 - S7, 英語[査読有り]
研究論文(学術雑誌)
「市民の科学に対する大学の支援に関する実践的研究」(略称「市民の科学」)プロジェクトの一環として、「サイエンスカフェ神戸」を創始した。このプロジェクトは、科学技術的課題に対する市民のエンパワーメント・システム構築をめざすもので、サイエンスカフェ開催はその第一段階として位置づけられる。2005年10月から2006年6月までに16回を開催し、科学コミュニケーションの新しいスタイルとして高い可能性を確認した。サイエンスカフェは現在各地に広がりつつあるが、「サイエンスカフェ神戸」では、文化としての科学を地域社会に根づかせることを大きな目的とし、運営に市民が主体的に参加し、様々な場で頻繁に開催されるようなあり方をゴールとして設定している点で特徴をもっている。「市民の科学」プロジェクトでは、次のステップとして、サイエンスカフェを通じて形成された緩やかなネットワークも利用しつつ、大学の支援のもとでの、環境などに関わる課題の市民による調査・研究の展開可能性を探ってゆく。
一般社団法人 日本科学教育学会, 2006年08月, 日本科学教育学会研究会研究報告, Vol. 21, No. 1, pp. 37-42 (1), 37 - 42, 日本語研究論文(学術雑誌)
Alpha-ray detector (ARD) will be on-board SELENE, a Japanese lunar orbiter to be launched around 2006. Primary target is the alpha particles emitted by Rn-222 and Po-210. Rn-222 is produced by the decay of U-238 and emanates from the lunar surface. It is trapped by the lunar gravity and decays with the half-life of 3.8 days emitting 5.490 MeV alpha particle. In the decay sequence of Rn-222, Po-210 emits alpha particle with the energy of 5.305 MeV. Time scale of the activity is dominated by the 21-year half-life of Pb-210. Thus, alpha particle intensity from Po-210 is an indicator of the change of radon emanation rate and change of crust condition due to seismic activity or impact events for the time scale of similar to 50 years, while that of Rn-222 reflects the current emanation rate. Results from Apollo 15, 16, and recent Lunar Prospector mission indicate that the average amount of radon on the lunar surface is much smaller than expected, and the radon-alpha distribution suggests that radon comes out through gas emanation from fissures of the lunar surface. We developed a large-area detector of 326 cm(2) for the ARD, which is 15-20 times larger than the detectors of Apollo and Lunar Prospector. Reduction of the background was achieved with the anti-coincidence by rejecting cosmic-ray tracks. It will enable: (1) precise global mapping of the radioactive material on the lunar surface; (2) identification of gas emanation location; (3) study of the radon gas emanation mechanism on the lunar surface and the origin of the lunar atmosphere; (4) obtaining information on the crustal movement during the last similar to 50 years. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.
ELSEVIER SCIENCE BV, 2006年, MOON AND NEAR-EARTH OBJECTS, 37 (1), 34 - 37, 英語[査読有り]
研究論文(学術雑誌)
科学・技術が高度に発達した社会において、(a)環境問題等の解決手段として、(b)知的探求活動として、市民の科学・技術にかかわる問題の調査・研究能力を高めてゆくこと(エンパワーメント)が大きな意味を持つ。我々は、神戸大学大学院総合人間科学研究科に設置された発達支援インスティテュート/ヒューマン・コミュニティ創成研究センターの研究プロジェクトとして「市民科学に対する大学の支援に関する実践的研究」の取り組みを始めた。本プロジェクトは、神戸を主なフィールドとして、幅広い年齢や素養をもつ市民が、大学の支援のもとに、科学リテラシーを高めるとともに、自らが調査・研究能力を獲得してゆく持続可能なシステムとそれを担う組織、人材のあり方を実践的に探り、日本の社会に適したモデルを構築することを目指す。
一般社団法人 日本科学教育学会, 2005年09月, 科教研報, 20・2, 47-51 (2), 47 - 51, 日本語研究論文(学術雑誌)
We propose an all-sky-survey at hard X-ray region (up to 80 keV) by using a formation flight of two satellites. They consist of a telescope satellite, carrying a super mirror focusing at hard X-ray region, and a detector satellite, carrying scintillator deposited CCDs (SDCCDs) for hard X-ray region. These two satellites are in the same orbit (altitude is about 500 km) in formation flight. Since the super mirror will be a thin-foil mirror with poor imaging capability. Therefore, they control the separation of 20 m+/-10 cm. Both satellites are in Keplerian orbit, then the viewing direction (from the detector satellite to the telescope satellite) scans along a large circle. Due to the precession of the orbit, the large circle gradually moves in the sky so that we can cover a large fraction of the sky. We can cover a large fraction of the sky without consuming a lot of fuel. However, the unseen regions are left near the ecliptic poles. This project, Formation Flight All Sky Telescope (FFAST), will be the first all sky survey at hard X-ray region.
SPIE-INT SOC OPTICAL ENGINEERING, 2005年, OPTICS FOR EUV, X-RAY, AND GAMMA-RAY ASTRONOMY II, 5900, 1 - 11, 英語研究論文(国際会議プロシーディングス)
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The ASCA satellite has observed the 50-ms pulsar PSR B0540-69 and its associated supernova remnant SNR 0540-693 in the Large Magellanic Cloud 15 times in total, at least once a year, between 1993 June and 1999 November, including six observations with the pulsar as the main target. In all the observations, a point-like X-ray source was clearly detected at the position of PSR B0540-69 and the X-ray pulsations were detected at large significance. Folded light curves are identical throughout the observations, showing one broad pulse with a small notch at the top. Pulse frequency history during the 6.4 yr of the ASCA observations is well characterized by a second-order polynomial with a breaking index of 2.10+/-0.05, assuming no glitches occurred during the period. The frequency history smoothly follows the Ginga and ROSAT results and connects to the RXTE results without a measurable discontinuity. The X-ray spectrum of the whole source is well represented by a single power-law model of photon index, alpha =2.00+/-0.02, and a small photoelectric absorption, N (H) =(4.3+/-0.2)x10(21) cm(-2) . The X-ray spectrum can also be represented by a pulsed power-law spectrum with photon index of 1.80+/-0.05 with 24 per cent in amplitude at 1 keV, embedded in a constant power-law component with photon index of 2.17+/-0.02 ascribed to a nebular component. Spectral properties of the X-ray emission from the pulsar and the nebula remain unchanged over the six years and are quite similar to those of the Crab pulsar and nebula.
OXFORD UNIV PRESS, 2002年07月, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 333 (3), 603 - 612, 英語[査読有り]
研究論文(学術雑誌)
ASCA observations of the supernova in M81, SN 1993J, 8-572 days after the explosion are presented. Utilizing a one-dimensional image-fitting to the Solid-State Imaging Spectrometer (SIS) data, energy spectra of the supernova in 0.5-8 keV are obtained. The spectrum showed drastic softening with a power-law photon index of 0.3-4, while the X-ray intensity decreased from 0.03 to 0.008 counts s(-1) SIS-1. The early phase of spectra requires two thermal emission components of different absorption columns if they are fitted with thermal models. The temperatures of two emission components cannot be well constrained with ASCA continuum spectra. However, the detection of an iron K emission line with ASCA and the hard X-ray spectra observed by OSSE on the Compton Gamma-Ray Observatory suggest that the two components have different temperatures: a few keV and about 100 keV. The properties of the two emission components are consistent with emissions from the front and reverse shocks of the supernova explosion. The drastic softening of the X-ray spectra is explained by the decrease of the absorption column density of the reverse shock component and the change of the major contributor to the soft X-ray band from the front to the reverse shocks.
IOP PUBLISHING LTD, 2002年01月, ASTROPHYSICAL JOURNAL, 565 (1), 419 - 429, 英語[査読有り]
研究論文(学術雑誌)
We report results of ASCA/GIS data analysis of 30 Dor C, a supernova remnant in the Large Magellanic Cloud. ASCA/GIS spectra suggests existence of a hard tail and that the northwestern part suffers higher interstellar absorption than the southeastern part does.
ASTRONOMICAL SOC PACIFIC, 2001年, NEW CENTURY OF X-RAY ASTRONOMY, 251, 250 - 251, 英語[査読有り]
研究論文(国際会議プロシーディングス)
We report on the spectral and temporal properties of the 50 ms pulsar PSR B0540-69 using ASCA archival data obtained during 1993 to 1995. From the spectral analysis it was found that the spectra of the whole (nebular and pulsed) emission and pulsed emission in the range 1-10 keV can be represented by a single power law of photon index, Gamma = 2.00 +/- 0.02 and Gamma(pulsed) = 1.7 +/- 0.3 respectively. The parameters for pulse frequency change during 1993-1995 were obtained using the 9 pulse frequency measurements with ASCA. The parameters derived from the ASCA observations are consistent with the previous measurements, suggesting high stability of this pulsar, Delta Omega/Omega less than or similar to 0.5 x 10(-7) over the past 10 years. These results confirm similarity of this pulsar with the Crab pulsar.
ASTRONOMICAL SOC PACIFIC, 2000年, PULSAR ASTRONOMY - 2000 AND BEYOND: IAU COLLOQUIUM 177, 202, 343 - 346, 英語研究論文(国際会議プロシーディングス)
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研究論文(学術雑誌)
Arabidopsis thaliana L. has 10 chromosomes that are small and similar in morphology. Molecular cytogenetics and image analyses were applied to characterize the somatic chromosomes. Prometaphase chromosomes were quantitatively analyzed based on their patterns of condensation, because they show a prominent uneven condensation along the chromosomes. The total length of the haploid prometaphase chromosomes is 16.5 μm, which is about 1.8 times the size of the metaphase chromosomes. We also detected the 45S (18S-5.8S-25S) and 5S rDNA loci by fluorescence in situ hybridization (FISH) and determined their locations on the chromosomes by the imaging methods. As a result, a quantitative chromosome map based on the condensation pattern was developed for the first time in Arabidopsis with the locations of rDNAs by using imaging methods. It is now possible to localize genes precisely on this map.
Japan Mendel Society, 2000年, Cytologia, 65 (3), 325 - 331, 英語[査読有り]
研究論文(学術雑誌)
We present results of simultaneous ASCA/Very Large Array (VLA) observations of the Wolf-Rayet star WR 147 (AS 431). This WN 8 star is an optical double and may be a WR+OB colliding wind binary system. The new observations place tight constraints on the origin of its X-ray and radio emission. The X-ray emission is due to a multitemperature, optically thin thermal plasma, with the dominant contribution coming from plasma at kT approximate to 1 keV. The absorption column density derived from the X-ray spectrum is N-H = 2 x 10(22) cm(-2), which agrees well with estimates based on the visual extinction but is too large to explain by wind absorption alone. The X-ray temperature structure is consistent with colliding wind shock emission, but the unabsorbed X-ray Luminosity L-x = 10(32.55) ergs s(-1) (0.5-10 keV) is several times smaller than that predicted from colliding wind shock models. The VLA data provide the most complete picture ever obtained of the radio spectral energy distribution of a WR star and consist of near-simultaneous observations at five different wavelengths (1.3, 2, 3.6, 6, and 21 cm). The radio emission consists of a thermal free-free component from the WR wind and a nonthermal component. If the nonthermal emission is due to relativistic particles accelerated by the Fermi mechanism in wind shocks, then the flux is expected to decline at high frequencies according to S-nu proportional to nu(-0.5). However, the observed falloff is much steeper and cannot be reproduced by a simple power law or by synchrotron models that assume power-law electron energy distributions. A surprising result is that the nonthermal emission can be accurately modeled as synchrotron radiation from relativistic electrons that are nearly monoergetic.
IOP PUBLISHING LTD, 1999年10月, ASTROPHYSICAL JOURNAL, 524 (1), 394 - 405, 英語[査読有り]
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We present an ASCA observation of the nearby spiral galaxy M51 (NGC 5194). We detected hard X-ray emission with a photon index of similar to 1.4 and a luminosity of L-x similar to 1.1 x 10(40) ergs s(-1) in the 2-10 keV band (assuming a distance of 9.6 Mpc). A strong fluorescent iron K line (equivalent width similar to 900 eV) was detected at 6.4 keV in the X-ray spectra. Such an intense iron line is characteristic of Seyfert 2 galaxies and strongly suggests the presence of a heavily obscured active galactic nucleus (AGN). However, the X-ray image is extended even at energies above 2 keV. From the strong iron line and the extended hard X-ray image we speculate that the AGN is obscured by matter with a hydrogen column density more than several times 10(23) cm(-2) and that the observed 2-10 keV X-ray flux is not dominated by emission from the AGN but rather by other components, such as low-mass X-ray binaries, which typically dominate the X-ray emission of normal spiral galaxies. Emission lines from O K, Ne K, Fe L, Mg K and Si K were detected in the soft energy spectra, which indicate the presence of hot gas. The soft component is well represented by a Raymond-Smith thermal plasma model (with kT similar to 0.4 keV), which suggests a lower iron abundance (<0.1 solar) than other elements (similar to 0.1-0.4 solar), or by a two temperature (kT similar to 0.3 keV and kT similar to 0.8 keV) model with similar to 0.1 solar abundance, which is reminiscent of the X-ray-emitting gas in starburst galaxies.
IOP PUBLISHING LTD, 1998年03月, ASTROPHYSICAL JOURNAL, 496 (1), 210 - 215, 英語[査読有り]
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We analyze results of a approximate to 25 ksec ASCA X-ray observation of the unusual Wolf-Rayet star HD 50896 (=EZ CMa). This WN5 star shows optical and ultraviolet variability at a 3.766 day period, which has been interpreted as a possible signature of a compact companion. Our objective was to search for evidence of hard X-rays (greater than or equal to 5 keV) which could be present if the WN5 wind is accreting onto a compact object. The ASCA spectra are dominated by emission below 5 keV and show no significant emission in the harder 5-10 keV range. Weak emission lines are present, and the X-rays arise in an optically thin plasma which spans a range of temperatures from less than or equal to 0.4 keVup to at least approximate to 2 keV. Excess X-ray absorption above the interstellar value is present, but the column density 22 is no larger than N-H similar to 10(22) cm(-2). The absorption-corrected X-ray luminosity L-x(0.5-10 keV)=10(32.85) erg s(-1) gives L-x/L(bol)approximate to 10(-6), a value that is typical of WN stars. No X-ray variability was detected. Our main conclusion is that the X-ray properties of HD 50896 are inconsistent with the behavior expected for wind accretion onto a neutron star or black hole companion. Alternative models based on wind shocks can explain most aspects of the X-ray behavior, and we argue that the hotter plasma near similar to 2 keV could be due to the WR wind shocking onto a normal (nondegenerate) companion. (C) 1998 Elsevier Science B.V.
ELSEVIER SCIENCE BV, 1997年11月, NEW ASTRONOMY, 3 (1), 37 - 49, 英語[査読有り]
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The x-ray properties of multinested thin-foil mirror x-ray telescopes (XRT's) on board ASCA, the Advanced Satellite for Cosmology and Astrophysics, were fully evaluated with an x-ray pencil beam. Scanning over the telescope aperture of 35 cm in diameter with an x-ray pencil beam, we found the effective area of a set of XRT's to be 325, 200, and 113 cm(2) at energies of 1.5, 4.5, and 8.0 keV, respectively. We derive the point-spread functions (PSF's) of the XRT's by measuring the image profile at the focal plane with an x-ray CCD. The PSF is found to exhibit a sharp core concentrated within 30 arcsec and a broad wing extended to 3 arcmin in half-power diameter. We also evaluate the contribution of stray light, which is caused by the single reflection of x rays by primary or secondary mirrors and by the backside reflection of the mirrors. To obtain the characteristics of the XRT in the energy region of 0.5-10.0 keV, incorporated with the measurements at discrete energies, we develop a ray-tracing method with the telescope design parameter, the PSF, and optical constants. In particular, we obtain the optical constants around the gold-atom M shell (Au-IM) absorption-edge energies by measuring the reflectivity of our mirror sample, with monochromatized x-rays in the energy range of 2.0-3.5 keV from synchrotron radiation. Taking into account the PSF's and optical constants, we find that our ray-tracing program can reproduce all these XRT performances. (C) 1995 Optical Society America.
OPTICAL SOC AMER, 1995年08月, APPLIED OPTICS, 34 (22), 4848 - 4856, 英語研究論文(学術雑誌)
We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, and Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last similar to 1500 yr came from Type Ia SNs.
UNIV CHICAGO PRESS, 1995年05月, ASTROPHYSICAL JOURNAL, 444 (2), L81 - L84, 英語[査読有り]
研究論文(学術雑誌)
The supernova remnant W49B with a center-filled X-ray morphology was observed with the Japanese X-ray satellite ASCA, and a spectrum of unprecedented quality was obtained with the X-ray CCD cameras on board. The observed spectrum is consistent with entirely thermal emission, and individual K emission lines from highly ionized atoms of Si, S, Ar, Ca, and Fe ase clearly resolved. It cannot, however, be reproduced by a single plasma component, even if non-equilibrium ionization is introduced, and requires multiple plasma components. The images constructed with photons of the Si-, S-, and Fe-lines, respectively, indicate that iron ions are mostly confined to the inner part of the remnant, and that those of the lower-Z elements form an outer envelope. This feature is interpreted as being due to a stratified distribution of elements.
ASTRONOMICAL SOC JAPAN, 1995年, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 47 (5), L31 - &, 英語[査読有り]
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[査読有り]
研究論文(国際会議プロシーディングス)
ASCA observed SN 1993J seven times between April 5 and October 24 in 1993. The 1-10 keV luminosity 10 d after the explosion was (15+/-4)x10(39) erg s(-1) and decreased monotonicly to (1.3+/-0.4)x10(39) erg s(-1) 210 d after the explosion, when a distance of 3.6 Mpc was assumed. The hardness ratio (2-10 keV/0.5-2 keV) significantly decreased during the course of the observations. The spectrum obtained from a sky region including not only SN 1993J but also the nearby X-ray source clearly shows an iron emission line. The correlation between the iron line flux with the SN 1993J flux suggests that the iron line emission originated in SN 1993J These observational results are discussed in the context of thermal X-ray emission from a hot region behind the shock due to the collision of the supernova ejecta with the pre-supernova stellar wind.
ASTRONOMICAL SOC JAPAN, 1994年, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 46 (4), L157 - L161, 英語[査読有り]
研究論文(学術雑誌)
A 30-m-long X-ray beam line has been built at the Institute of Space and Astronautical Science (ISAS) to evaluate the performance of X-ray optical instruments for space programs, in particular for the X-ray telescope onboard the Astro-D (Asca) satellite. This beam line consists of an X-ray generator, a 30-m-long vacuum duct, and measuring chambers. Strong and stable X-ray pencil beams from Al, Ti, Cu, Mo and W targets are available with the parallelism of several arcs [full width at half maximum (FWHM)]. Three kinds of detectors are prepared: a conventional gas proportional counter equipped with a thin plastic window, a one-dimensional position-sensitive proportional counter with a Be window, and a charge-coupled device (CCD) modified for X-ray measurements. At the present compact beam line, instead of giant systems of hundreds of meters, the combination of a strong X-ray (0.2-10 keV) pencil beam and translation stages enables us to examine the entire aperture of large X-ray optical instruments of up to 40 cmand 1 m in length. © 1993 The Japan Society of Applied Physics.
1993年, Japanese Journal of Applied Physics, 32 (10 R), 4805 - 4813, 英語[査読有り]
研究論文(学術雑誌)
We detected an X-ray outburst in the Vela-Puppis region with the All Sky Monitor (ASM) aboard Ginga on 1990 November 22. Following observations by the Large Area proportional Counter (LAC) revealed that this outburst consisted of two transient sources, GS0834-430 and GS0836-429, accidentally in the same field of view of the LAC by a separation of only 0.4 degree. These two transient X-ray sources were subsequentially monitored with the LAC until 1991 May. GS 0834-430 was identified by an X-ray pulsar with a period of 12.s3. This pulsar shows a power-law energy spectrum with a photon index of approximately 0.9, and with a high-energy cutoff that is typical of X-ray pulsars. GS 0836-429 was identified by an X-ray burster, which shows typical type-I bursts approximately every 2 h.
ASTRONOMICAL SOC JAPAN, 1992年, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 44 (6), 641 - 647, 英語[査読有り]
研究論文(学術雑誌)
An X-ray light curve of SN 1987A was obtained from Ginga over a 1000-day period since its outburst. X-rays from the SN appear to comprise two separate components: a hard and a soft component. Hard X-rays were first detected in July 1987, reached a maximum near the end of 1987, and declined steadily through January 1989. Later, the hard component has been close to or below the detection limit. A remarkable soft X-ray flare conclusively from SN 1987A occurred in January 1988. In addition, soft X-rays were occasionally observed significantly in the region of SN 1987A.
ASTRONOMICAL SOC JAPAN, 1991年, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 43 (2), 213 - 223, 英語[査読有り]
研究論文(学術雑誌)
This paper summarises Ginga X-ray observations of SN 1987 A.
C S I R O PUBLICATIONS, 1991年, PROCEEDINGS ASTRONOMICAL SOCIETY OF AUSTRALIA, 9 (1), 107 - 107, 英語[査読有り]
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A formation ight astronomical survey telescope (FFAST) is a new project in hard X-ray covering a large sky area. In particular, it will focus on the energy range up to 80 keV. It consists of two small satellites that will go in a formation ight (FF). FF enables us to remove a long optical bench from a hard X-ray telescope. Instead, we need an active control system to form a telescope. One is an X-ray telescope satellite carrying a super mirror that covers the energy range up to 80 keV. The super mirror is a thin-foil mirror (focal length is 12 m) that is almost identical to that developed for ASTRO-H. The other is a detector satellite carrying a CCD camera that is almost identical to that developed for ASTRO-H. The CCD employed in the FFAST is a scintillation deposited CCD (SDCCD). The X-ray enters from the front side while the scintillator is attached to the back side. Low energy X-rays (below 15 keV) will be absorbed in the depletion layer of the CCD and detected as usual. High energy X-rays (above 15 keV) will pass through the depletion layer and be detected in the scintillator. Scintillation lights will be detected by the CCD. The mirror satellite will also carry an optical camera monitoring the detector satellite. The detector satellite will carry LED targets periodically ushing. With this system, we can measure the distance between two satellites. The detector satellite also carries a thruster system to keep the distance constant so that we can form an X-ray telescope. There are two types of FF. One is a powered FF with which we can keep pointing to a fixed star that is fuel consuming. The other is a relative circular orbit two satellites are in Keplerian orbit with keeping a constant distance with which we will scan a large sky region without using fuel so much. The biggest objective of the FFAST is to study the distribution of the AGN in various luminosities. We will detect sources ten times fainter than those detected by Swift/BAT and scan ten times larger area than that scanned by Nu-STAR. We will detect Compton-thick AGNs that may reveal a new aspect of the evolution of the universe.
SPIE, 2014年, Proceedings of SPIE - The International Society for Optical Engineering, 9144, 9144, 英語[査読有り]
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV). The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of Delta E similar to 7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued.
SPIE-INT SOC OPTICAL ENGINEERING, 2010年, SPACE TELESCOPES AND INSTRUMENTATION 2010: ULTRAVIOLET TO GAMMA RAY, 7732, 77320Z-77320Z-18, 英語Japan's NeXT mission has, been approved for the Phase-A in 2007. At, present NeXT is in the process of transition to the Phase-B. One of the unique freature of the mission is an imaging spectroscopy in unprecedentedly wide energy region from 0.5 to 80 keV. The X-Ray Telescope (XRT) system covers the energy by means of grazing incidence reflective optics. International collaboration has been formed for the project and design and basic study have been carried out so far. Current baseline specification includes two hard X-ray telescopes which are combined with the Hard X-ray. Imager (Si + CdTe pixel or strip) and cover 5 to 80 keV, and two soft, X-ray telescopes which cover 0.3 to about 20 keV, one combined with a high resolution X-ray micro-calorimeter and the other with an X-ray CCD. Both of hard and soft X-ray mirrors employ same optical design; tightly-nested conically-approximated thin-foil Wolter-I optics. The mission requirements for XRT system have been identified as 300 cm(2) at 30 keV for the hard X-ray telescope in total and 400 cm(2) at 6 keV for the soft X-ray telescope per unit. The requirement oil the point spread function is 1.7 arcmin in HPD, as well as the goal being 1.2 arcmin Based oil the current level of technology all the mission requirements are expected to be satisfied.
SPIE-INT SOC OPTICAL ENGINEERING, 2008年, SPACE TELESCOPES AND INSTRUMENTATION 2008: ULTRAVIOLET TO GAMMA RAY, PTS 1 AND 2, 7011, 英語[査読有り]
[査読有り]
We analyze results of a ≈ 25 ksec ASCA X-ray observation of the unusual Wolf-Rayet star HD 50896 (= EZ CMa). This WN5 star shows optical and ultraviolet variability at a 3.766 day period, which has been interpreted as a possible signature of a compact companion. Our objective was to search for evidence of hard X-rays (≥ 5 keV) which could be present if the WN5 wind is accreting onto a compact object. The ASCA spectra are dominated by emission below 5 keV and show no significant emission in the harder 5-10 keV range. Weak emission lines are present, and the X-rays arise in an optically thin plasma which spans a range of temperatures from ≤ 0.4 keV up to at least ≈ 2 keV. Excess X-ray absorption above the interstellar value is present, but the column density is no larger than NH ∼ 1022cm-2. The absorption-corrected X-ray luminosity Lx (0.5-10keV) = 1032.85 erg s-1 gives Lx/Lbol ≈ 10-6, a value that is typical of WN stars. No X-ray variability was detected. Our main conclusion is that the X-ray properties of HD 50896 are inconsistent with the behavior expected for wind accretion onto a neutron star or black hole companion. Alternative models based on wind shocks can explain most aspects of the X-ray behavior, and we argue that the hotter plasma near ∼ 2 keV could be due to the WR wind shocking onto a normal (nondegenerate) companion. © 1998 Elsevier Science B.V.
Elsevier, 1998年, New Astronomy, 3 (1), 37 - 49, 英語Status of gamma-ray burst observation is summarized together with the recent result obtained by the Gamma-ray Burst Detector (GBD) on board Ginga satellite. Gamma-ray bursts are thought to originate in the vicinity of neutron stars because of the fast time variability, spectral features and several-second periodicity observed in some peculiar events. The GBD on board Ginga have detected about ten gamma-ray burst candiates so far. The burst spectra are confirmed to approach to black-body radiation at the end of bursts in some events. The temperature and photon flux of the black-body-like spectra gives the ratio of the radius and distance of the burst sources, (R/km)/(D/kpc)∿1.
宇宙航空研究開発機構, 1988年03月, 宇宙科学研究所報告. 特集, 21, 47 - 50, 日本語口頭発表(一般)
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公開講演,セミナー,チュートリアル,講習,講義等
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