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東京電力ホールディングス福島第一原子力発電所(1F)の事故が発生した後、原子力規制庁からの委託を受け、平成31年度に近沿岸海域等における放射性物質の状況調査を実施した。本報告書は、平成31年度に実施した調査により得られた結果をまとめたものである。1F近傍の近沿岸海域における海水・海底土の今後の中長期的な放射性物質濃度調査の在り方について、科学的根拠に基づき、「海域モニタリングの進め方」に必要な考え方の整理を行った。中長期的な調査方法を決めるために必要な基礎情報として、海底地形・海底土分布調査を実施し、海底の地形と底質の粒度分布の関連性も把握を試みた。さらに、採泥調査を行い、福島県沿岸域において柱状試料を採取し、放射性セシウム濃度を分析した。河川から流入する懸濁物質に含まれる放射性セシウムの動態を把握するため、セジメントトラップを用いて沈降物を採取し、放射性セシウム濃度を測定した。また、放射性セシウムの河川からの流入評価のために河川前面の海底土表層の放射性セシウム濃度の計測を実施した。得られた結果より1F前面海域の海底土の放射性物質分布の動態について推定を行った。さらに、平成25年度から実施していた曳航式モニタリングデータの再解析を実施し、沿岸域における放射性セシウム分布推定図の精度向上を試みた。, After the accident at TEPCO Fukushima Daiichi Nuclear Power Station (1F), marine monitoring survey on radioactive substances have been conducted with financially supported by the Nuclear Regulatory Agency from FY2019. Results obtain in the project in FY2019 are presented in this report. Based on scientific grounds, the concept necessary for "progress of sea area monitoring" was arranged for the future medium- to long-term investigation of radiocesium concentrations. As basic information of survey frequency revise, a seabed topography and sediment distribution survey was conducted, and an attempt was made to understand the relationship between the seabed topography and the grain size distribution of bottom sediment. A columnar core sample was collected in the coastal area and analyzed for radioactive cesium concentration. In order to understand the dynamics of radioactive cesium contained in suspended matter flowing in from a river, suspended solids was collected using a sediment trap and the concentration of radioactive cesium was measured. We re-analyzed the towed monitoring data that had been implemented since 2013, and tried to improve the accuracy of the radioactive cesium distribution estimation map in the coastal area., 著者所属: 日本原子力研究開発機構(JAEA), JAEA-Research 2020-008

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会議情報: 第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 著者人数: 17名, Meeting Information: 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

会議情報: 第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, Meeting Information: 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

会議情報: 第1回観測ロケットシンポジウム（2018年7月17日-18日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, Meeting Information: 1st Sounding Rocket Symposium (July 17-18, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

会議情報: 第1回観測ロケットシンポジウム（2018年7月17日-18日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, 著者人数: 34名, Meeting Information: 1st Sounding Rocket Symposium (July 17-18, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

会議情報: 第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 著者人数: 15名, Meeting Information: 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

会議情報: 第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, Meeting Information: 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

会議情報: 第13回宇宙科学シンポジウム (2013年1月8日-9日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 著者人数: 59名, Meeting Information: 13th Space Science Symposium (January 8-9, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

We propose SPICA/MCS monitoring observation at North Ecliptic Pole region to search MIR-variable faint obscured AGNs to study faint end early phase AGN properties. We have carried out deep near to mid infrared survey with AKARI/IRC (2-24 μm) and follow-up multi-wavelength observations (X-ray-radio), and found many AGN candidates. However there is possibility to miss identify obscured AGNs which can be just-activated early phase ones. SPICA/MCS monitoring survey will give us a great help to investigate these early phase AGNs. When we carry out 1 hour observation, once per half a month, then we can survey 12 MCS-field-of-views (12 × 5′ × 5′), and approximately 50 type-1 AGN and approximately 50-200 type-2 AGN detection is expected. This survey can monitor long time scale (3-5 years) variability of these AGNs., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

We propose a narrowband imaging survey of star-forming galaxies at re-ionisation era. The survey will exploit the widefield imaging capability of SPICA/MCS by using narrowband filter to detect H emission from the redshift 7 less than or equal to z less than or equal to 10. We estimated the feasibility of this survey, showing that the number of detectable sources highly depends on the IMF of the stellar population. Since the age constraints are fairly strong at such high redshifts, and extremely young star-forming galaxies are presumably less dusty, the survey should give the first direct and meaningful constraints on the IMF of population III (popIII) star formation., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshift; the AKARI all sky survey in 6 bands (9-160 micrometers), and the AKARI NEP survey in 9 bands (2-24 micrometers). The AKARI performed all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160 micrometers) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, we measure the total infrared luminosity (L(sub TIR)) of individual galaxies, and thus, the total infrared luminosity density of the local Universe much more precisely than previous work. In the AKARI NEP wide field, AKARI has obtained deep images in the mid-infrared (IR), covering 5.4 deg(exp 2). However, our previous work was limited to the central area of 0.25 deg(exp 2) due to the lack of deep optical coverage. To rectify the situation, we used the newly advent Subaru telescope's Hyper Suprime-Cam to obtain deep optical images over the entire 5.4 deg(exp 2) of the AKARI NEP wide field. With this deep and wide optical data, we, for the first time, can use the entire AKARI NEP wide data to construct restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at z is less than 0.15 and greater than 2.2. A continuous 9-band filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24 micrometers by the AKARI satellite allowed us to estimate restframe 8 micrometers and 12 micrometers luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from z = 0 to z = 2.2, all probed by the AKARI satellite., Meeting Information: The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 会議情報: 第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, 形態: カラー図版あり

We have started the study on the specification of filters and grisms for SPICA Mid-Infrared Camera and Spectrometer (MCS; Kataza et al. 2012) Wide Field Camera (WFC) within the framework of MCS Filter Working Group (FWG). The FWG activity aims to obtain the baseline specification of imaging filters and grisms optimized for the maximum science output in any scientific fields of “extragalactic science”, “ISM science” and “planetary science” by taking account of the technical constraints. The resultant baseline specifications will be opened to wider science members of SPICA project and FWG will get a more effective baseline set of filters and grisms for WFC by reflecting the feedback received. In this article, the latest progress report on the specification of filters and grisms for WFC studied by the MCS FWG is given., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

We present the results of our star-forming galaxy survey of distant clusters of galaxies using Subaru (H ) and AKARI (MIR). By comparing the H and MIR data, we revealed that dust-obscured star-forming galaxies are most preferentially located in the cluster outskirts at z approximately 1. We propose to extend this H - and IR-based environmental study to higher redshifts, but a problem so far is that the existing MIR-FIR surveys always suffer from their limited depths. We can overcome this problems with the wide-field mid-infrared (MIR) camera on-board SPICA (5′FoV), which will allow us an efficient, and extremely deep MIR survey of distant clusters. In particular, the expected high sensitivity of SPICA at 20-40 μm regime promotes us to extend IR galaxy survey out to z = 2-4 (i.e. the “peak epoch” of galaxy evolution) based on their rest-frame 8 μm feature. We provide a quick overview of our recent progress with the MAHALO-Subaru collaboration, and then discuss how significantly SPICA can improve our understanding of the environmental effects on galaxy evolution in the early universe., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

The wide field camera of MCS onboard SPICA will have an unique capability of slit-less grism spectroscopy survey. It utilizes wide (5′ × 5′) field of view (FOV), and spectra of all sources within the FOV would be acquired at once with grisms mounted on filter wheels, covering 5-38 μm in total. We simulate the slit-less spectroscopy images of a realistic deep universe with galaxies populated according to their luminosity function in order to examine detectability of galaxies as a function of their luminosity and redshift while quantitatively assessing source overlapping problem., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

We aim to study star-forming galaxies by using a blind spectroscopic survey at mid-infrared (MIR) wavelengths to understand evolution of their star formation rate (SFR) and specific SFR (SFR per stellar mass) up to z in the order of 0.5, by paying particular attention to their Polycyclic Aromatic Hydrocarbon (PAH) properties. We conducted a low-resolution (R approximately equal to 50) slitless spectroscopic survey at 5-13 micrometers of 9 micrometers flux-selected sources (approximately greater than 0.3 mJy) around the North Ecliptic Pole with the Infrared Camera (IRC) onboard AKARI. We identified 48 PAH galaxies with PAH 6.2, 7.7, and 8.6 micrometers features at z approximately less than 0.5. The rest-frame optical-MIR spectral energy distributions (SEDs) based on CFHT and AKARI/IRC imaging are produced and analyzed in conjunction with the PAH spectroscopy. The rest-frame SEDs of all PAH galaxies have a universal shape with stellar and 7.7 micrometers (PAH) bumps, except that the PAH enhancement (luminosity ratio of the 7.7 micrometers PAH feature over the 3.5 micrometers stellar bump) significantly varies as a function of the PAH luminosities. We identified a PAH-enhanced population at z approximately less than 0.35, whose SEDs and luminosities are typical of luminous infrared galaxies. They show particularly larger PAH enhancement at high luminosity, implying that they are vigorous star-forming galaxies with elevated specific SFR. Our composite starburst model that combines a young and dusty starburst with a very old population can successfully reproduce most SED characteristics., Meeting Information: The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, Number of authors: 27, Physical characteristics: Original contains color illustrations, 会議情報: 第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, 著者人数: 27名, 形態: カラー図版あり

We present our recent activities on the development of new Ge photoconductors for far-infrared (far-IR) astronomy. Using the surface-activated wafer bonding (SAB) method provided by Mitsubishi Heavy Industries, we fabricated a Ge p+-i p+-i junction device with clean abrupt junction, which basically possesses a Blocked-Impurity-Band-type (BIB-type) structure. We measured the far-IR sensitivity of the device at 1.7K using a blackbody source and spectral response curves at 2.8K using a Fourier transform spectrometer. The device shows considerably higher sensitivity and wider spectral coverage than a conventional bulk Ge:Ga device, demonstrating promising applicability of SAB Ge p+-i junction devices to BIB-type Ge detectors., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

SPICA Coronagraph Instrument (SCI) is an instrument dedicated for direct detection and characterization of exoplanets and also for other science that needs a high-contrast imaging and spectroscopic capability in the near to mid-infrared wavelengths. We will present the major science cases for exoplanets from the instrument proposal of SCI. Thanks to the high-contrast imaging and spectroscopic capability, we will be able to tackle the various problems on the exoplanet science. SCI will give us the unique opportunity to observationally understand the formation process of Jovian planets, which is still poorly understood, by measuring temperatures of young Jovian planets. Spectroscopy of planet atmospheres will enable us to reveal the chemical compositions by measuring the abundances of various important molecules such as CO, CH4, NH3, H2O, H2 etc. We will also access to the structure of Jovian atmosphere, for example the existence of thermal inversion which is known for our Solar system planets. Furthermore, the direct detection of icy giants around early-type stars with SCI will open a new window to investigate these enigmatic planets., The clerical error of an author's name: T. KOMATSU, Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Number of authors: 57, Physical characteristics: Original contains color illustrations, 著者名の誤記: T. KOMATSU, 著者人数: 57名, 形態: カラー図版あり

We present our recent activities on laboratory experiments of an infrared detector and metal mirrors for the SPICA/SCI. We plan to adopt a Si:As detector array for the SCI to cover the wavelength region from 4 to 28 μm. We have evaluated a bias dependence of the cutoff wavelength of the Si:As detector. Our results suggest a possible extension of the cutoff wavelength through efficient increase in the sensitivity at longer wavelengths. We have also measured the wavelength dependence of reflectance on the detector surface to verify that the detector receives the light of wavelengths longer than the designed cutoff wavelength. We also fabricated prototype metal mirrors and evaluated their surface roughness and surface figure errors. The roughness satisfies the SCI requirement, while the figure errors do not. We have identified a problem in each of the fabrication and evaluation processes, which will lead to the improvements of the surface figure errors and the measurement accuracies., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

会議情報: 第18回宇宙科学シンポジウム (2018年1月9日-10日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 著者人数: 16名ほか, Meeting Information: 18th Space Science Symposium (January 9-10, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

We have investigated the dependence of galaxy properties on their surrounding environments with AKARI/IRC. We found less star-forming galaxies tend to be in dense region at z = 0.8 whereas at z greater than 0.8 universe, the star formation are more active in denser region, consistent with the previous work. As an indicator of star formation, we used 8 μm to 4.5 μm flux ratio, which is reduced by the radiation from Active Galactic Nuclei so that it can trace pure star forming galaxies. Such a useful indicator could be used by only AKARI which has a continuous wavelength coverage between 2-24 μm. In future work we suggest to extend this work to z = 3.5 universe using SPICA which has also continuous wavelength coverage at mid-infrared and has a great spatial resolution, which is needed to avoid source blend in dense regions., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

Infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe these both at low and high redshifts. The AKARI performed an all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160 μm) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can measure the total infrared luminosity (L(sub TIR)) of individual galaxies much more precisely, and thus, the total infrared luminosity density of the local Universe. In the AKARI NEP deep field, we construct restframe 8 μm, 12 μm, and total infrared (TIR) luminosity functions (LFs) at 0.15 less than z less than 2.2 using 4128 infrared sources. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24 μm) by the AKARI satellite allows us to estimate restframe 8 μm and 12 μm luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from z=0 to z=2.2, all probed by the AKARI satellite. The next generation space infrared telescope, SPICA, will revolutionize our view of the infrared Universe with superb sensitivity of the cooled 3m space telescope. We conclude with our survey proposal and future prospects with SPICA., Meeting Information: SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

著者人数: 68名

Accepted: 2017-07-26