Curriculum Vitaes
Profile Information
- Affiliation
- Professor, Institute of Space and Astronautical Science, Department of Astrophysics, Japan Aerospace Exploration Agency
- J-GLOBAL ID
- 201801002962836691
- researchmap Member ID
- B000323419
- External link
Research Interests
2Research Areas
1Research History
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Aug, 2005 - Present
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Apr, 1992 - Jul, 2005
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Aug, 2001 - Dec, 2004
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Apr, 1991 - Mar, 1992
Education
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Apr, 1986 - Mar, 1991
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Apr, 1980 - Mar, 1986
Committee Memberships
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Nov, 2020 - Present
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Apr, 2020 - Present
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Apr, 2020 - Present
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Apr, 2020 - Present
Papers
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The Astrophysical Journal, Apr 1, 2024
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The Astrophysical Journal, Jan 1, 2024
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Physical Review Letters, 131(19), Nov 9, 2023
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The Astrophysical Journal, Nov 1, 2023
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Physical review letters, 131(10) 109902, Sep 8, 2023This corrects the article DOI: 10.1103/PhysRevLett.130.211001.
Misc.
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ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS XXVI, 521 205-208, 2019We are developing the web-based quick data analysis tools JUDO2 and UDON2 at DARTS (http: //darts.isas.jaxa.jp). JUDO2 adopts Aladin Lite to display various astronomical survey data. In particular, we have created HiPS data of Suzaku, MAXI, ASCA and Swift, and publish them from DARTS. In addition, we made various types of the constellation data in HiPS format. Recently, thanks to cooperation by ESA-sky team, the XMM fields of view (footprints) and direct links to the XMM-archive at ESA are made available in JUDO2. UDON2 allows users to extract spectra and light-curves of MAXI, Suzaku and ASCA data. Users can display favorite targetstars or sky regions in JUDO2, and jump to UDON2 to quickly analyze these targets. We are going to add JAXA's other astronomical data (e.g. Akari pointing data, Hitomi) to JUDO2 and UDON2.
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ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS XXVIII, 523 515-518, 2019CALET (CALorimetric Electron Telescope) has been installed and operational on the Japanese Experiment Module Exposed Facility of the International Space Station (ISS) since August 2015. We describe the Web analaysis system for the CALET Gamma-ray Burst Monitor (CGBM), which is publicly available from DARTS.
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ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS XXVI, 521 46-49, 2019Over the past few years the Hierarchical Progressive Survey (HiPS) has become a key method for the distribution of all -sky reference data. Today, HiPS represents about 100 TB of data, and is expected to double each year as the network of a dozen of HiPS providers including ESAC, JAXA, CADC and CDS grows. HiPS data sets are used by thousands of users per day through various HiPS aware clients: Aladin, MIZAR, Aladin Lite, and Aladin-Lite based ESASky and JUDO2. We expect that this technology will be one of the main methods for the distribution of surveys - images, catalogs and cubes - for the next decade. In this extremely fast growing environment, we will discuss why the HiPS network is an excellent candidate for long term management of all-sky reference data. We highlight how the intrinsic HiPS architecture based on the well known HEALPix geometry, a simple tile structure, straightforward distribution method based only on a basic HTTP server, and being standardised by IVOA, constitutes an extremely robust foundation for a system which will support all-sky data distribution for a long time.
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Publications of the Astronomical Society of Japan, 70(3), Feb 14, 2018We present results from the Hitomi X-ray observation of a young<br /> composite-type supernova remnant (SNR) G21.5$-$0.9, whose emission is dominated<br /> by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80<br /> keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager<br /> (SXI) and Hard X-ray Imager (HXI) show a significant break in the continuum as<br /> previously found with the NuSTAR observation. After taking into account all<br /> known emissions from the SNR other than the PWN itself, we find that the Hitomi<br /> spectra can be fitted with a broken power law with photon indices of<br /> $\Gamma_1=1.74\pm0.02$ and $\Gamma_2=2.14\pm0.01$ below and above the break at<br /> $7.1\pm0.3$ keV, which is significantly lower than the NuSTAR result ($\sim9.0$<br /> keV). The spectral break cannot be reproduced by time-dependent particle<br /> injection one-zone spectral energy distribution models, which strongly<br /> indicates that a more complex emission model is needed, as suggested by recent<br /> theoretical models. We also search for narrow emission or absorption lines with<br /> the SXS, and perform a timing analysis of PSR J1833$-$1034 with the HXI and<br /> SGD. No significant pulsation is found from the pulsar. However, unexpectedly,<br /> narrow absorption line features are detected in the SXS data at 4.2345 keV and<br /> 9.296 keV with a significance of 3.65 $\sigma$. While the origin of these<br /> features is not understood, their mere detection opens up a new field of<br /> research and was only possible with the high resolution, sensitivity and<br /> ability to measure extended sources provided by an X-ray microcalorimeter.
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SPACE TELESCOPES AND INSTRUMENTATION 2018: ULTRAVIOLET TO GAMMA RAY, 10699, 2018The ASTRO-H mission was designed and developed through an international collaboration of JAXA, NASA, ESA, and the CSA. It was successfully launched on February 17, 2016, and then named Hitomi. During the in-orbit verification phase, the on-board observational instruments functioned as expected. The intricate coolant and refrigeration systems for soft X-ray spectrometer (SXS, a quantum micro-calorimeter) and soft X-ray imager (SXI, an X-ray CCD) also functioned as expected. However, on March 26, 2016, operations were prematurely terminated by a series of abnormal events and mishaps triggered by the attitude control system. These errors led to a fatal event: the loss of the solar panels on the Hitomi mission. The X-ray Astronomy Recovery Mission (or, XARM) is proposed to regain the key scientific advances anticipated by the international collaboration behind Hitomi. XARM will recover this science in the shortest time possible by focusing on one of the main science goals of Hitomi, "Resolving astrophysical problems by precise high-resolution X-ray spectroscopy".(1) This decision was reached after evaluating the performance of the instruments aboard Hitomi and the mission's initial scientific results, and considering the landscape of planned international X-ray astrophysics missions in 2020's and 2030's.Hitomi opened the door to high-resolution spectroscopy in the X-ray universe. It revealed a number of discrepancies between new observational results and prior theoretical predictions. Yet, the resolution pioneered by Hitomi is also the key to answering these and other fundamental questions. The high spectral resolution realized by XARM will not offer mere refinements; rather, it will enable qualitative leaps in astrophysics and plasma physics. XARM has therefore been given a broad scientific charge: "Revealing material circulation and energy transfer in cosmic plasmas and elucidating evolution of cosmic structures and objects". To fulfill this charge, four categories of science objectives that were defined for Hitomi will also be pursued by XARM; these include (1) Structure formation of the Universe and evolution of clusters of galaxies; (2) Circulation history of baryonic matters in the Universe; (3) Transport and circulation of energy in the Universe; (4) New science with unprecedented high resolution X-ray spectroscopy. In order to achieve these scientific objectives, XARM will carry a 6 x 6 pixelized X-ray micro-calorimeter on the focal plane of an X-ray mirror assembly, and an aligned X-ray CCD camera covering the same energy band and a wider field of view. This paper introduces the science objectives, mission concept, and observing plan of XARM.
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Aug 31, 2017This document presents HiPS, a hierarchical scheme for the description,<br /> storage and access of sky survey data. The system is based on hierarchical<br /> tiling of sky regions at finer and finer spatial resolution which facilitates a<br /> progressive view of a survey, and supports multi-resolution zooming and<br /> panning. HiPS uses the HEALPix tessellation of the sky as the basis for the<br /> scheme and is implemented as a simple file structure with a direct indexing<br /> scheme that leads to practical implementations.
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ASTROPHYSICAL JOURNAL LETTERS, 837(1), Mar, 2017X-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.
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years of MAXI: monitoring X-ray Transients, 2017
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Meeting Abstracts of the Physical Society of Japan, 71 503-503, 2016
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Dec 1, 2015The Galactic Ridge X-ray Emission (GRXE) spectrum has strong iron emission<br /> lines at 6.4, 6.7, and 7.0~keV, each corresponding to the neutral (or<br /> low-ionized), He-like, and H-like iron ions. The 6.4~keV fluorescence line is<br /> due to irradiation of neutral (or low ionized) material (iron) by hard X-ray<br /> sources, indicating uniform presence of the cold matter in the Galactic plane.<br /> In order to resolve origin of the cold fluorescent matter, we examined the<br /> contribution of the 6.4~keV line emission from white dwarf surfaces in the hard<br /> X-ray emitting symbiotic stars (hSSs) and magnetic cataclysmic variables (mCVs)<br /> to the GRXE. In our spectral analysis of 4~hSSs and 19~mCVs observed with<br /> Suzaku, we were able to resolve the three iron emission lines. We found that<br /> the equivalent-widths (EWs) of the 6.4~keV lines of hSSs are systematically<br /> higher than those of mCVs, such that the average EWs of hSSs and mCVs are<br /> $179_{-11}^{+46}$~eV and $93_{-3}^{+20}$~eV, respectively. The EW of hSSs<br /> compares favorably with the typical EWs of the 6.4~keV line in the GRXE of<br /> 90--300~eV depending on Galactic positions. Average 6.4~keV line luminosities<br /> of the hSSs and mCVs are $9.2\times 10^{39}$ and $1.6\times<br /> 10^{39}$~photons~s$^{-1}$, respectively, indicating that hSSs are intrinsically<br /> more efficient 6.4~keV line emitters than mCVs. We compare expected<br /> contribution of the 6.4 keV lines from mCVs with the observed GRXE 6.4 keV line<br /> flux in the direction of $(l,b) \approx (28.5\arcdeg, 0\arcdeg$). We conclude<br /> that almost all the 6.4 keV line flux in GRXE may be explained by mCVs within<br /> current undertainties of the stellar number densities, while contribution from<br /> hSSs may not be negligible.
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日本理科教育学会全国大会要項, (65) 198-198, 2015
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大会講演予講集, 107 295-295, 2015
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Dec 3, 2014In this white paper we describe the prospects for ASTRO-H for the study of<br /> outflows from active galactic nuclei. The most important breakthroughs in this<br /> field are expected to arise from the high spectral resolution and sensitivity<br /> in the Fe-K band, combined with broad-band sensitivity over the full X-ray band<br /> and spectral capabilities also at lower energies. The sensitivity in the Fe-K<br /> region allows to extend the absorption measure distribution of the outflow out<br /> to the highest ionisation states accessible, where observations with current<br /> X-ray missions indicate that most of the outflowing gas is to be found. Due to<br /> the high-resolution and sensitivity it will also be able to give the definitive<br /> proof for the existence of ultra-fast outflows, and if so, characterise their<br /> physical properties in great detail. These ultra-fast outflows carry very large<br /> amounts of energy and momentum, and are of fundamental importance for feedback<br /> studies. We show how the ASTRO-H observations in general can help to constrain<br /> numerical models for outflows. The link to reflection and emission processes is<br /> also discussed, as well as the possible relation between outflows and<br /> relativistic emission lines. Finally, we discuss the prospects for other<br /> related categories of objects like BAL quasars, partially covered sources and<br /> Compton thick outflows.
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SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY, 9144, 2014WF-MAXI is a soft X-ray transient monitor proposed for the ISS/JEM. Unlike MAXI, it will always cover a large field of view (20 % of the entire sky) to detect short transients more efficiently. In addition to the various transient sources seen by MAXI, we hope to localize X-ray counterparts of gravitational wave events, expected to be directly detected by Advanced-LIGO, Virgo and KAGRA in late 2010's. The main instrument, the Soft X-ray Large Solid Angle Cameras (SLC) is sensitive in the 0.7-12 keV band with a localization accuracy of similar to 0.1 degrees. The Hard X-ray Monitor (HXM) covers the same sky field in the 20 keV-1 MeV band.
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40th COSPAR Scientific Assembly. Held 2-10 August 2014, in Moscow, Russia, Abstract id. E1.5-54-14., 2014
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Astrophysical Journal, 779(1), Dec 10, 2013We report the results from X-ray studies of the newly discovered black hole candidate MAXI J1305-704 based on Suzaku and Swift observations in the low/hard and high/soft states, respectively. The long Suzaku observation shows two types of clear absorption dips, both of which recur on a dip interval of 9.74 ± 0.04 hr, which we identify with the orbital period. There is also partially ionized absorption in the nondip (persistent) emission in both the high/soft state and, very unusually, the low/hard state. However, this absorption (in both states) has substantially lower ionization than that seen in other high inclination systems, where the material forms a homogeneous disk wind. Here instead the absorption is most likely associated with clumpy, compact structures associated with the dipping material, which we see uniquely in this source likely because we view it at a very large inclination angle. A large inclination angle is also favored, together with a low black hole mass, to explain the high disk temperature seen in the fairly low luminosity high/soft state, as Doppler boosting enhances the disk temperature at high inclination. The disk radius inferred from these data is significantly smaller than that of the soft component seen in the low/hard state, supporting models where the disk is truncated at low luminosities. We find, however, that the lack of variability power on timescales of ∼50 s in the Suzaku low/hard state data is difficult to explain, even with a low-mass black hole. © 2013. The American Astronomical Society. All rights reserved..
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JAXA research and development report, 12 29-37, Mar, 2013MAXI, the only all-sky X-ray monitor on the International Space Station (ISS), started observation in 2009 August. MAXI has two major objectives, 1) to issue rapid alerts of new X-ray novae/transients into astronomers worldwide and 2) to acquire long-term all-sky X-ray data. Thanks to the good network connection between the ISS and the ground station, we can obtain 70% of MAXI data through the real-time communication path. We built a ground system (referred as "MAXI-DB") to handle real-time data efficiently; with the MAXI-DB and the alert system we issued 29150 rapid alerts in the three years since MAXI started observation. It is crucial to provide MAXI data to scientists all over the world, because MAXI data includes rich information. The MAXI data has been released to public step by step. Daily data products including images, light curves and energy spectra for 29300 pre-registered X-ray sources have been archived on the MAXI web site (http://maxi.riken.jp/top). Since the MAXI data taken by the slit-scan observation includes complex information on all-sky X-ray sources, it is not easy to collect data for a given source quickly on demand. We thus developed the MAXI on-demand archive system which sort all event data in orders of the sky region and the time. The new archive system is confirmed to process data for any celestial source 29100 times faster than the former system.
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JAXA research and development report, 12 19-27, Mar, 2013Explosive growth of data volume in scientific domains has caused demand of machine processing of the massive scientific data. In this paper we propose several schemes of similarity search over astronomical X-ray data for X-ray outbursts. Specifically, we first detect outbursts from the original data, followed by smoothing for reducing noise and normalization. Having detected outburst patterns, we apply dynamic time warping (DTW), which is known to be robust against time scaling to evaluate similarities between two outburst patterns.We propose several variations based on DTW by taking features of the outburst patterns and requirements for the similarity search;we apply derivative DTW, which is a variant of DTW, and apply sliding windows to evaluate partial similarities. We evaluate feasibility of the proposed schemes by experiments using real X-ray astronomy data.
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JAXA research and development report, 12 9-18, Mar, 2013We have been working on methods of visualizing space science data. For the purpose of education and public outreach,devices built on mobile computing platforms (iOS and Android, etc.) are fascinating ones to represent space science data. While mobile devices require a large amount of computing resources to visualize science data, wireless data services for mobile devices are not yet fast enough to instantly transfer the sufficient amount of data. This paper introduces a method to progressively download science data in order to reduce the latency. The proposed method here is also expected to reduce memory usage and CPU usage in comparison with conventional space science data I/O libraries.
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全国大会講演論文集, 2012(1) 633-635, Mar 6, 2012近年の科学分野で扱われるデータの量は膨大である.その筆頭が天文学であり,今も多くのデータが蓄積されている.その内,現在注目されているものの一つに X線天体がある.動的タイムワーピング(Dynamic Time Warping,以下「DTW」)とは,音声や株価といった時系列データを比較する際よく用いられる手法である.これを利用するとDTW距離という類似度を示す一つの数値が得られる.本研究では,全天X線監視装置「MAXI」から提供されるX線天体観測データを対象に,X線天体が起こすバースト現象のデータに対しDTWを用いた類似検索を行い,類似したパターンを示す天体を発見する手法を提案する.
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第74回全国大会講演論文集, 2012(1) 633-634, Mar 6, 2012近年の科学分野で扱われるデータの量は膨大である．その筆頭が天文学であり，今も多くのデータが蓄積されている．その内，現在注目されているものの一つに X線天体がある．動的タイムワーピング(Dynamic Time Warping，以下「DTW」)とは，音声や株価といった時系列データを比較する際よく用いられる手法である．これを利用するとDTW距離という類似度を示す一つの数値が得られる．本研究では，全天X線監視装置「MAXI」から提供されるX線天体観測データを対象に，X線天体が起こすバースト現象のデータに対しDTWを用いた類似検索を行い，類似したパターンを示す天体を発見する手法を提案する．
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JAXA research and development report, 11 47-56, Mar, 2012With the advance of digital technologies, huge amounts of astronomical data are being produced today by ground-based observatories and astronomical satellites. In order to efficiently extract scientific information from these data, a convenient method to visualize a large amount of astronomical data is required. Meanwhile, recent digital planetarium technologies allow us to display high resolution images on a planetarium dome. Thus, in this paper, we have investigated possibilities to use digital planetarium as a tool to visualize a large amount of astronomical data. We have made a digital planetarium program using actual astronomical observation data, mainly from JAXA's scientific satellites. Such a planetarium program also can provide educational, public outreach and entertainment purposes.
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JAXA research and development report, 11(11-007) 7-11, Mar, 2012We report on current status of the Astronomical Data Sonification Project. We have sonified astronomical data sets, including data from X-ray pulsars, Geo-magnetic Kp indices, etc. and have published these results. We also developed a sound-based, interactive, data-plotting program. This software enables the visually impaired to turn astronomical data into meaningful sounds. In this paper we summarize the progress of the project and also discuss future plans.
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JAXA research and development report, 11(11-007) 13-22, Mar, 2012For the purpose of education and public outreach, this paper introduces methods of visualization and sonification of space science data in a time sequence. The data used in this paper are as follows: Observation data and orbital elements of X-ray astronomy satellites ASCA and Suzaku, PWS data observed by the aurora observation satellite AKEBONO, Geomagnetic Kp indices. X-ray observation data contains the attributes (position, time, pulse-height) of each X-ray events detected. In conjunction with the visualization of orbital elements of the satellite, it is possible to virtually experience the observation by means of visualization and sonification of the data. Also it is possible to hear the radio wave around the earth and geomagnetic variations by means of sonification of corresponding data. We used different method for sonification of the PWS data (wide-band distribution of radio waves) and that of Kp indices (described as musical diagrams).
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Proceedings of SPIE - The International Society for Optical Engineering, 8443, 2012The 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.
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Journal of health sciences, Nihon Fukushi University, 14 1-9, Mar 30, 2011We are developing a sound-based, interactive, data-plotting program to enable the visually impaired to turn astronomical data into meaningful sounds. The sonification software, called "splot", would be available to any scientist to analyze data. Splot reads ASCII data files containing various plotting commands and other data, and then outputs sounds corresponding to the data instead of plotting to a display or a printer. Input data for splot is partially compatible with "qdp", a data-plotting program developed by NASA HEASARC. In this paper, we report the status of development. In the current version, splot only sonifies a one-dimensional histogram and thus remains an experimental production. Before releasing this software, we must extend its functions for a suitable field test and construct a data-analysis environment for the visually impaired.
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ASTRONOMY & ASTROPHYSICS, 520, Sep, 2010Context. White dwarfs (WDs) in cataclysmic variables (CVs) are important experimental laboratories where the electron degeneracy is taking place on a macroscopic scale. Magnetic CVs increase in number especially in the hard X-ray band (greater than or similar to 10 keV) thanks to sensitive hard X-ray missions. Aims. From X-ray spectroscopy, we estimate the masses of nearby WDs in moderately-magnetized CVs, or Intermediate Polars (IPs). Methods. Using the Suzaku satellite, we aquired wide-band spectra of 17 IPs, covering 3-50 keV. An accretion column model of Suleimanov et al. (2005, A&A, 435, 191) and an optically-thin thermal emission code were used to construct a spectral emission model of IPs with resolved Fe emission lines. By simultaneously fitting the Fe line complex and the hard X-ray continuum of individual spectra, the shock temperature and the WD mass were determined with a better accuracy than in previous studies. Results. We determined the WD masses of the 17 IPs with statistical fitting errors of less than or similar to 0.1-0.2 M-circle dot in many cases. The WD mass of a recently-found IP, IGR J17195-4100, was also estimated for the first time (1.03(-0.22)(+0.24) M-circle dot). The average WD mass of the sample is 0.88 +/- 0.25 M-circle dot. When our results were compared with previous X-ray mass determinations, we found significant deviation in a few systems although the reason of this is unclear. The iron abundance of the accreting gas was also estimated, and confirmed the previously reported sub-solar tendency in all sources with better accuracy.
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Jun 28, 2010We report the detection of a time variable OVII line emission in a deep 100<br /> ks Suzaku X-ray Imaging Spectrometer spectrum of the Galactic Ridge X-ray<br /> emission. The observed line intensity is too strong (11+/-2 line unit or photon<br /> cm^-2 s^-1 str^-1) to be emitted inside the heavily obscured Galactic disk. It<br /> showed a factor of two time variation which shows a significant (~4 sigma)<br /> correlation with the solar wind O^7+ ion flux. The high line intensity and the<br /> good time correlation with the solar wind strongly suggests that it originated<br /> from geocoronal solar wind charge exchange emission. We discuss the X-ray line<br /> intensity considering a line of sight direction and also theoretical<br /> distribution models of the neutral hydrogen and solar wind around the Earth.<br /> Our results indicate that X-ray observationsof geocoronal solar wind charge<br /> exchange emission can be used to constrain these models.
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The astronomical herald, 103(7) 445-456, Jun 20, 2010
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Oct 2, 2008In order to elucidate origin of the Galactic Ridge X-ray Emission, we<br /> analyzed Suzaku data taken at various regions along the Galactic plane and<br /> studied their Fe-K emission line features. Suzaku resolved the Fe line complex<br /> into three narrow lines at ~6.4 keV,~6.7 keV and ~6.97 keV, which are K-lines<br /> from neutral (or low-ionized), He-like, and H-like iron ions, respectively. The<br /> 6.7 keV line is clearly seen in all the observed regions and its longitudinal<br /> distribution is consistent with that determined from previous observations. The<br /> 6.4 keV emission line was also found in various Galactic plane regions (b~0).<br /> Differences in flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines<br /> between the Galactic plane and the Galactic center regions are studied and its<br /> implication is discussed.
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Butsuri, 63(9) 670-677, Sep 5, 2008In space astronomy, most observation data are publicly released after short proprietary periods. Much more scientific results are expected from scientific satellites by opening the data toward scientists all over the world and archiving the data permanently, than otherwise. To that end, space organizations in many countries are developing public space-science data archives, which may be considered precious scientific legacies of the mankind. Space-science data has a characteristic that its use does not conflict with ethics or economic interests. Taking this characteristic positively, promoting the international sharing of the space-science data may enhance mutual understanding between the countries. Consequently, "Security by Science" may be achieved.
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HIGH ENERGY, OPTICAL, AND INFRARED DETECTORS FOR ASTRONOMY III, 7021, 2008We are developing the CALorimetric Electron Telescope, CALET, mission for the Japanese Experiment Module Exposed Facility, JEM-EF, of the International Space Station. Major scientific objectives are to search for the nearby cosmic ray sources and dark matter by carrying out a precise measurement of the electrons in 1 GeV - 20 TeV and gamma rays in 20 MeV - several 10 TeV. CALET has a unique capability to observe electrons and gamma rays over 1 TeV since the hadron rejection power can be larger than 105 and the energy resolution better than a few % over 100 GeV. The detector consists of an imaging calorimeter with scintillating fibers and tungsten plates and a total absorption calorimeter with BGO scintillators. CALET has also a capability to measure cosmic ray H, He and heavy ions up to 1000 TeV. It also will have a function to monitor solar activity and gamma ray transients. The phase A study has started on a schedule of launch in 2013 by H-II Transfer Vehicle (HTV) for 5 year observation.
Presentations
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第1回 SPARC Japan セミナー2020 「研究データ公開：フルオープンと制限公開の境界線」, Oct 2, 2020 Invited
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JpGU-AGU Joint Meeting 2020:Virtual ユニオンセッション U-12 「地球惑星科学の進むべき道10 ビッグデータとオープンサイエンス」, Jul 15, 2020 Invited
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20 Years of Chandra Science Symposium
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The 29th annual international Astronomical Data Analysis Software & Systems (ADASS)
Professional Memberships
1Research Projects
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2016 - Mar, 2019
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, 2009 - 2011
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2007 - 2009
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Grants-in-Aid for Scientific Research Grant-in-Aid for international Scientific Research, Japan Society for the Promotion of Science, 1992 - 1994
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科学研究費助成事業 奨励研究(特別研究員), 日本学術振興会, 1990 - 1990
