研究者業績

鈴木 仁研

スズキ トヨアキ  (Toyoaki Suzuki)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 宇宙物理学研究系 准教授
学位
博士 (理学)(2007年9月 東京大学)

研究者番号
30534599
J-GLOBAL ID
202101020754871070
researchmap会員ID
R000016314

論文

 68
  • Takao Nakagawa, Hideo Matsuhara, Umi Enokidani, Toyoaki Suzuki, Shunsuke Baba, Yasuhiro Hirahara, Hidehiro Kaneda, Ryoichi Koga, Yuan Li, Biao Zhao, Daiki Takama, Hiroshi Sasago, Takehiko Wada, Toshihiro Nakaoka, Taiki Eda, Ryota Kakihara, Yoshinori Shohmitsu, Takuya Hosobata, Noboru Ebizuka, Yutaka Yamagata, Shota Notsu, Hideko Nomura
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave 236-236 2024年8月23日  
  • Tsubasa Kondo, Akino Kondo, Katsuhiro L Murata, Takuma Kokusho, Shinki Oyabu, Toyoaki Suzuki, Risako Katayama, Hidehiro Kaneda
    Publications of the Astronomical Society of Japan 76(5) 1041-1049 2024年8月9日  
    Abstract Hydrocarbon dust is one of the dominant components of interstellar dust, which mainly consists of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons. While hydrocarbon dust is thought to be processed in interstellar radiation fields or shocks, detailed processing mechanisms are not completely understood yet. We investigate the processing of hydrocarbon dust by analyzing the relation between the luminosities emitted by hydrocarbon dust and the total infrared luminosities $(L_{\mathrm{IR } })$ for 138 star-forming galaxies at redshift $z \lt 0.3$. Using near-infrared 2.5–5$\, \mu {\rm m}$ spectra obtained with AKARI, we derived the luminosities of the aromatic hydrocarbon feature at 3.3$\, \mu {\rm m}$ ($L_\mathrm{aromatic}$) and the aliphatic hydrocarbon feature at 3.4–3.6$\, \mu {\rm m}$ ($L_\mathrm{aliphatic}$). We also derived $L_\mathrm{IR}$ and the radiation field strength by modeling the spectral energy distributions of the 138 galaxies with AKARI, WISE, and IRAS photometry data. We find that galaxies with higher $L_\mathrm{IR}$ tend to exhibit lower $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios. Furthermore, we find that there is an anti-correlation between $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios and the radiation field strength, and also that the galaxies with low $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios are dominated by merger galaxies. These results support the suggestion that hydrocarbon dust is processed through photodissociation in strong radiation fields and/or shocks during merging processes of galaxies; the $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratio is likely to decrease in such harsh interstellar conditions since the aliphatic bonds are known to be chemically weaker than the aromatic bonds.
  • Keisuke Shinozaki, Toyoaki Suzuki, Noriko Y. Yamasaki, Yutaro Sekimoto, Tadayasu Dotani, Keisuke Yoshihara, Hiroyuki Sugita, Shoji Tsunematsu, Kenichi Kanao
    Cryogenics 138 103795-103795 2024年3月  
  • Shugo Oguri, Tadayasu Dotani, Masahito Isshiki, Shota Iwabuchi, Tooru Kaga, Frederick T. Matsuda, Yasuyuki Miyazaki, Baptiste Mot, Ryo Nagata, Katsuhiro Narasaki, Hiroyuki Ogawa, Toshiaki Okudaira, Kimihide Odagiri, Thomas Prouve, Gilles Roudil, Yasutaka Satoh, Yutaro Sekimoto, Toyoaki Suzuki, Kazuya Watanuki, Seiji Yoshida, Keisuke Yoshihara
    Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave 2022年8月27日  
  • Akio K. Inoue, Hidehiro Kaneda, Toru Yamada, Yuichi Harikane, Daisuke Ishihara, Tadayuki Kodama, Yutaka Komiyama, Takashi Moriya, Kentaro Motohara, Hideko Nomura, Masami Ouchi, Shinki Oyabu, Toyoaki Suzuki, Takehiko Wada, Issei Yamamura
    Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave 2022年8月27日  
  • Hiroshi Maeshima, Kosei Matsumoto, Yasuhiro Hirahara, Takao Nakagawa, Ryoichi Koga, Yusuke Hanamura, Takehiko Wada, Koichi Nagase, Shinki Oyabu, Toyoaki Suzuki, Takuma Kokusho, Hidehiro Kaneda, Daichi Ishikawa
    Journal of Electronic Materials 51(2) 564-576 2022年2月  査読有り
  • Kimihide Odagiri, Masaru Saijo, Keisuke Shinozaki, Frederick Matsuda, Shugo Oguri, Toyoaki Suzuki, Hiroyuki Ogawa, Yutaro Sekimoto, Tadayasu Dotani, Kazuya Watanuki, Ryo Sugimoto, Keisuke Yoshihara, Katsuhiro Narasaki, Masahito Isshiki, Seiji Yoshida, Thomas Prouve, Jean-Marc Duval, Keith L. Thompson
    SPACE TELESCOPES AND INSTRUMENTATION 2022: OPTICAL, INFRARED, AND MILLIMETER WAVE 12180 2022年  
    LiteBIRD is a JAXA-led international project that aims to test representative inflationary models by performing an all-sky cosmic microwave background radiation (CMB) polarization survey for 3 years at the Sun-Earth Lagrangian point L2. We aim to launch LiteBIRD in the late 2020s. The payload module (PLM) is mainly composed of the Low-Frequency Telescope (LFT), the Mid-Frequency Telescope and High-Frequency Telescope (MHFT), and a cryo-structure. To conduct the high-precision and high-sensitivity CMB observations, it is required to cool the telescopes down to less than 5 K and the detectors down to 100 mK. The high temperature stability is also an important design factor. It is essential to design and analyze the cryogenic thermal system for PLM. In this study, the heat balance, temperature distribution, and temperature stability of the PLM for the baseline design are evaluated by developing the transient thermal model. The effect of the Joule-Thomson (JT) coolers cold tip temperature variation, the periodical changes in subK Adiabatic Demagnetization Refrigerator (ADR) heat dissipation, and the satellite spin that generates the variable direction of solar flux incident are implemented in the model. The effect of contact thermal conductance in the LFT and the emissivity of the V-groove on the temperature distribution and heat balance are investigated. Based on the thermal analysis, it was confirmed that the PLM baseline design meets the requirement of the temperature and the cooling capability of the 4K-JT cooler. In addition, the temperatures of the V-groove and the LFT 5-K frame are sufficiently stable for the observation. The temperature stability of the Low Frequency Focal Plane (LF-FP) is also discussed in this paper.
  • Saijo Masaru, Nakagawa Takao, Ogawa Hiroyuki, Shinozaki Keisuke, Sawada Kenichiro, Matsuhara Hideo, Tokoku Chihiro, Suzuki Toyoaki, Isobe Naoki
    International Conference on Environmental Systems 2021年7月  査読有り
  • T. Suzuki, S. Oyabu, S. K. Ghosh, D. K. Ojha, H. Kaneda, H. Maeda, T. Nakagawa, J. P. Ninan, S. Vig, M. Hanaoka, F. Saito, S. Fujiwara, T. Kanayama
    Astronomy & Astrophysics 651 A30-A30 2021年7月  査読有り筆頭著者
  • Risako Katayama, Hidehiro Kaneda, Takuma Kokusho, Kumiko Morihana, Toyoaki Suzuki, Shinki Oyabu, Mitsuyoshi Yamagishi, Takuro Tsuchikawa
    Publications of the Astronomical Society of Japan 72(5) 2020年10月2日  査読有り
    <title>Abstract</title> Centaurus A (Cen A) is one of the most famous galaxies hosting an active galactic nucleus (AGN), where the interaction between AGN activities and surrounding interstellar and intergalactic media has been investigated. Recent studies reported detections of Hα emission from clouds in the galactic halo toward the northeast and southwest of the nucleus of Cen A, suggesting that AGN jets may have triggered star formation there. We performed near-infrared line mapping of Cen A with the IRSF 1.4 m telescope, using the narrow-band filter tuned for Paβ, from which we find that Paβ emission is not detected significantly from either of the northeast or southwest regions. The upper limit of the Paβ/Hα ratio in the northeast region is compatible with that expected for a typical H ii region, in line with the scenario that AGNs have triggered star formation there. On the other hand, the upper limit of Paβ/Hα in the southwest region is significantly lower than that expected for a typical H ii region. A possible explanation of the low Paβ/Hα ratio in the southwest region is the scattering of Hα and Paβ photons from the center of Cen A by dust grains in the halo clouds. From the upper limit of Paβ/Hα in the southwest region, we obtain constraints on the dust size distribution, which is found to be compatible with those seen in the interstellar medium of our Galaxy.
  • Misaki Hanaoka, Hidehiro Kaneda, Toyoaki Suzuki, Takuma Kokusho, Shinki Oyabu, Daisuke Ishihara, Mikito Kohno, Takuya Furuta, Takuro Tsuchikawa, Futoshi Saito
    Publications of the Astronomical Society of Japan 72(1) 2020年2月1日  査読有り
    <title>Abstract</title> Galactic infrared (IR) bubbles, which can be seen as shell-like structures at mid-IR wavelengths, are known to possess massive stars within their shell boundaries. In our previous study (Hanaoka, 2019, PASJ, 71, 6), we expanded the research area to the whole Galactic plane ($0^{\circ } \le l \le 360^{\circ }$, $|b| \le 5^{\circ }$) and studied systematic differences in the shell morphology and the IR luminosity of the IR bubbles between inner and outer Galactic regions. In this study, utilizing high spatial-resolution data of AKARI and WISE in the mid-IR and Herschel in the far-IR, we investigate the spatial distributions of dust components around each IR bubble to discuss the relation between the star-formation activity and the dust properties of the IR bubbles. For the 247 IR bubbles studied in Hanaoka (2019, PASJ, 71, 6), 165 IR bubbles are investigated in this study, which have the Herschel data ($|b|\le 1^{\circ }$) and known distances. We created their spectral energy distributions on a pixel-by-pixel basis around each IR bubble, and decomposed them with a dust model consisting of polycyclic aromatic hydrocarbons (PAHs), hot dust, warm dust and cold dust. As a result, we find that the offsets of dust heating sources from the shell centers in inner Galactic regions are systematically larger than those in outer Galactic regions. Many of the broken bubbles in inner Galactic regions show large angles between the offset and the direction of the broken shell from the center. Moreover, the spatial variations of the PAH intensity and cold dust emissivity around the IR bubbles in inner Galactic regions are larger than those in outer Galactic regions. We discuss these results in light of the interstellar environments and the formation mechanism of the massive stars associated with the IR bubbles.
  • T. Kokusho, H. Kaneda, M. Bureau, T. Suzuki, K. Murata, A. Kondo, M. Yamagishi, T. Tsuchikawa, T. Furuta
    Astronomy & Astrophysics 622 A87-A87 2019年2月  査読有り
    <italic>Context.</italic> The properties of the dust in the cold and hot gas phases of early-type galaxies (ETGs) are key to understanding ETG evolution. <italic>Aims.</italic> We aim to conduct a systematic study of the dust in a large sample of local ETGs, focusing on relations between the dust and the molecular, atomic, and X-ray gas of the galaxies, as well as their environment. <italic>Methods.</italic> We estimated the dust temperatures and masses of the 260 ETGs from the ATLAS3D survey, using fits to their spectral energy distributions primarily constructed from AKARI measurements. We also used literature measurements of the cold (CO and H <sc>I</sc>) and X-ray gas phases. <italic>Results.</italic> Our ETGs show no correlation between their dust and stellar masses, suggesting inefficient dust production by stars and/or dust destruction in X-ray gas. The global dust-to-gas mass ratios of ETGs are generally lower than those of late-type galaxies, likely due to dust-poor H <sc>I</sc> envelopes in ETGs. They are also higher in Virgo Cluster ETGs than in group and field ETGs, but the same ratios measured in the central parts of the galaxies only are independent of galaxy environment. Slow-rotating ETGs have systematically lower dust masses than fast-rotating ETGs. The dust masses and X-ray luminosities are correlated in fast-rotating ETGs, whose star formation rates are also correlated with the X-ray luminosities. <italic>Conclusions.</italic> The correlation between dust and X-rays in fast-rotating ETGs appears to be caused by residual star formation, while slow-rotating ETGs are likely well evolved, and have therefore exhausted their dust. These results appear consistent with the postulated evolution of ETGs, whereby fast-rotating ETGs form by mergers of late-type galaxies and associated bulge growth, while slow-rotating ETGs form by (dry) mergers of fast-rotating ETGs. Central cold dense gas appears to be resilient against ram pressure stripping, suggesting that Virgo Cluster ETGs may not suffer strong related suppression of star formation.
  • Misaki Hanaoka, Hidehiro Kaneda, Toyoaki Suzuki, Takuma Kokusho, Shinki Oyabu, Daisuke Ishihara, Mikito Kohno, Takuya Furuta, Takuro Tsuchikawa, Futoshi Saito
    Publications of the Astronomical Society of Japan 71(1) 2019年1月1日  査読有り
  • Toyoaki Suzuki, Hidehiro Kaneda, Takehiko Wada, Souta Ukai, Misaki Hanaoka, Kazuyuki Shichi, Hiroki Maeda, Shinki Oyabu, Kentaroh Watanabe
    Japanese Journal of Applied Physics 57(11) 116701-116701 2018年11月1日  査読有り筆頭著者
  • Daisuke Ishihara, Shinki Oyabu, Misato Fukagawa, Takuma Kokusho, Toyoaki Suzuki, Takehiko Wada, Naoki Isobe, Jungmi Kwon, Hideo Matsuhara, Koichi Nagase, Takao Nakagawa, Takafumi Ootsubo, Mitsuyoshi Yamagishi, Itsuki Sakon, Kohji Tsumura, Hiroshi Shibai, Mitsunobu Kawada, Hidehiro Kaneda, Takuya Furuta, takurou Tsuchikawa
    Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave 2018年7月12日  
  • T. Suzuki, H. Kaneda, T. Onaka, M. Yamagishi, D. Ishihara, T. Kokusho, T. Tsuchikawa
    Monthly Notices of the Royal Astronomical Society 477(3) 3065-3075 2018年7月1日  査読有り筆頭著者
    We used a data set from AKARI and Herschel images at wavelengths from 7 to 500 μm to catch the evidence of dust processing in galactic winds in NGC 1569. Images show a diffuse infrared (IR) emission extending from the galactic disc into the halo region. The most prominent filamentary structure seen in the diffuse IR emission is spatially in good agreement with the western Hα filament (western arm). The spatial distribution of the F350/F500 map shows high values in regions around the super-star clusters (SSCs) and towards the western arm, which are not found in the F250/F350 map. The colour-colour diagram of F250/F350-F350/F500 indicates high values of the emissivity power-law index (βc) of the cold dust component in those regions. From a spectral decomposition analysis on a pixel-by-pixel basis, a βc map shows values ranging from ~1 to ~2 over the whole galaxy. In particular, high βc values of ~2 are observed only in the regions indicated by the colour-colour diagram. Since the average cold dust temperature in NGC 1569 is ~30 K, βc &lt 2.0 in the far-IR and sub-mm region theoretically suggests emission from amorphous grains, while βc = 2.0 suggests that from crystal grains. Given that the enhanced βc regions are spatially confined by the HI ridge that is considered to be a birthplace of the SSCs, the spatial coincidences may indicate that dust grains around the SSCs are grains of relatively high crystallinity injected by massive stars originating from starburst activities and that those grains are blown away along the HI ridge and thus the western arm.
  • P. R. Roelfsema, H. Shibai, L. Armus, D. Arrazola, M. Audard, M. D. Audley, C.M. Bradford, I. Charles, P. Dieleman, Y. Doi, L. Duband, M. Eggens, J. Evers, I. Funaki, J. R. Gao, M. Giard, A. di Giorgio, L. M. González Fernández, M. Griffin, F. P. Helmich, R. Hijmering, R. Huisman, D. Ishihara, N. Isobe, B. Jackson, H. Jacobs, W. Jellema, I. Kamp, H. Kaneda, M. Kawada, F. Kemper, F. Kerschbaum, P. Khosropanah, K. Kohno, P. P. Kooijman, O. Krause, J. van der Kuur, J. Kwon, W. M. Laauwen, G. de Lange, B. Larsson, D. van Loon, S. C. Madden, H. Matsuhara, F. Najarro, T. Nakagawa, D. Naylor, H. Ogawa, T. Onaka, S. Oyabu, A. Poglitsch, V. Reveret, L. Rodriguez, L. Spinoglio, I. Sakon, Y. Sato, K. Shinozaki, R. Shipman, H. Sugita, T. Suzuki, F. F. S. van der Tak, J. Torres Redondo, T. Wada, S. Y. Wang, C. K. Wafelbakker, H. van Weers, S. Withington, B. Vandenbussche, T. Yamada, I. Yamamura
    Publications of the Astronomical Society of Australia 35 2018年  
    <title>Abstract</title>Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity. SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope, cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions. SPICA instruments offer spectral resolving power ranging from <italic>R</italic> ~50 through 11 000 in the 17–230 μm domain and <italic>R</italic> ~28.000 spectroscopy between 12 and 18 μm. SPICA will provide efficient 30–37 μm broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 μm. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of ~5 × 10−20 W m−2 (5σ/1 h)—over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.
  • L. Spinoglio, A. Alonso-Herrero, L. Armus, M. Baes, J. Bernard-Salas, S. Bianchi, M. Bocchio, A. Bolatto, C. Bradford, J. Braine, F. J. Carrera, L. Ciesla, D. L. Clements, H. Dannerbauer, Y. Doi, A. Efstathiou, E. Egami, J. A. Fernández-Ontiveros, A. Ferrara, J. Fischer, A. Franceschini, S. Gallerani, M. Giard, E. González-Alfonso, C. Gruppioni, P. Guillard, E. Hatziminaoglou, M. Imanishi, D. Ishihara, N. Isobe, H. Kaneda, M. Kawada, K. Kohno, J. Kwon, S. Madden, M. A. Malkan, S. Marassi, H. Matsuhara, M. Matsuura, G. Miniutti, K. Nagamine, T. Nagao, F. Najarro, T. Nakagawa, T. Onaka, S. Oyabu, A. Pallottini, L. Piro, F. Pozzi, G. Rodighiero, P. Roelfsema, I. Sakon, P. Santini, D. Schaerer, R. Schneider, D. Scott, S. Serjeant, H. Shibai, J. D.T. Smith, E. Sobacchi, E. Sturm, T. Suzuki, L. Vallini, F. Van der Tak, C. Vignali, T. Yamada, T. Wada, L. Wang
    Publications of the Astronomical Society of Australia 34 2017年11月16日  
    IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ∼ 6.
  • T. Kokusho, H. Kaneda, M. Bureau, T. Suzuki, K. Murata, A. Kondo, M. Yamagishi
    ASTRONOMY & ASTROPHYSICS 605 2017年9月  
    Context. The star formation properties of early-type galaxies (ETGs) are currently the subject of considerable interest, particularly whether they differ from the star formation properties of gas-rich spirals. Aims. We perform a systematic study of star formation in a large sample of local ETGs with polycyclic aromatic hydrocarbon (PAH) and dust emission, focusing on the star formation rates (SFRs) and star formation efficiencies (SFEs) of the galaxies. Methods. Our sample is composed of the 260 ETGs from the ATLAS(3D) survey, from which we used the cold gas measurements (HI and CO). We estimated the SFRs from stellar, PAH, and dust fits to spectral energy distributions created from new AKARI measurements and with literature data from WISE and 2MASS. Results. The mid-infrared luminosities of non-CO-detected galaxies are well correlated with their stellar luminosities, showing that they trace (circum) stellar dust emission. CO-detected galaxies show an excess above these correlations, uncorrelated with their stellar luminosities, indicating that they likely contain PAHs and dust of interstellar origin. PAH and dust luminosities of CO-detected galaxies show tight correlations with their molecular gas masses; the derived current SFRs are typically 0.01-1 M circle dot yr(-1). These SFRs systematically decrease with stellar age at fixed stellar mass, while they correlate nearly linearly with stellar mass at fixed age. The majority of local ETGs follow the same star formation law as local star-forming galaxies and their current SFEs do not depend on either stellar mass or age. Conclusions. Our results clearly indicate that molecular gas is fueling current star formation in local ETGs, which appear to acquire this gas via mechanisms regulated primarily by stellar mass. The current SFEs of local ETGs are similar to those of local star-forming galaxies, indicating that their low SFRs are likely due to smaller cold gas fractions rather than a suppression of star formation.
  • D. Ishihara, T. Kondo, H. Kaneda, T. Suzuki, K. Nakamichi, S. Takaba, H. Kobayashi, S. Masuda, T. Ootsubo, J. Pyo, T. Onaka
    Astronomy & Astrophysics 603 A82-A82 2017年7月  査読有り
  • Misaki Hanaoka, Hidehiro Kaneda, Shinki Oyabu, Yasuki Hattori, Kotomi Tanaka, Sota Ukai, Kazuyuki Shichi, Takehiko Wada, Toyoaki Suzuki, Kentaroh Watanabe, Koichi Nagase, Shunsuke Baba, Chihiro Kochi
    Publications of The Korean Astronomical Society 32(1) 351-353 2017年3月31日  
  • Yamagishi Mitsuyoshi, Kaneda Hidehiro, Oyabu Shinki, Ishihara Daisuke, Onaka Takashi, Shimonishi Takashi, Suzuki Toyoaki
    Publications of The Korean Astronomical Society 32(1) 141-145 2017年3月  査読有り
  • Hironobu Makitsubo, Takehiko Wada, Hirokazu Kataza, Makoto Mita, Toyoaki Suzuki, Keita Yamamoto
    JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES 38(2) 206-214 2017年2月  
    We propose an all-silicon multi-layer interference filter composed solely of silicon with sub-wavelength structure (SWS) in order to realize high performance optical filters operating in the THz frequency region with robustness against cryogenic thermal cycling and mechanical damage. We demonstrate fabrication of a three-layer prototype using well-established common micro-electro-mechanical systems (MEMS) technologies as a first step toward developing practical filters. The measured transmittance of the three-layer filter agrees well with the theoretical transmittances calculated by a simple thin-film calculation with effective refractive indices as well as a rigorous coupled-wave analysis simulation. We experimentally show that SWS layers can work as homogeneous thin-film interference layers with effective refractive indices even if there are multiple SWS layers in a filter.
  • H. Kaneda, D. Ishihara, S. Oyabu, M. Yamagishi, T. Wada, L. Armus, M. Baes, V. Charmandaris, B. Czerny, A. Efstathiou, J. A. Fernández-Ontiveros, A. Ferrara, E. González-Alfonso, M. Griffin, C. Gruppioni, E. Hatziminaoglou, M. Imanishi, K. Kohno, J. Kwon, T. Nakagawa, T. Onaka, F. Pozzi, D. Scott, J. D.T. Smith, L. Spinoglio, T. Suzuki, F. Van der Tak, M. Vaccari, C. Vignali, L. Wang
    Publications of the Astronomical Society of Australia 34 2017年  
    The mid-infrared range contains many spectral features associated with large molecules and dust grains such as polycyclic aromatic hydrocarbons and silicates. These are usually very strong compared to fine-structure gas lines, and thus valuable in studying the spectral properties of faint distant galaxies. In this paper, we evaluate the capability of low-resolution mid-infrared spectroscopic surveys of galaxies that could be performed by SPICA. The surveys are designed to address the question how star formation and black hole accretion activities evolved over cosmic time through spectral diagnostics of the physical conditions of the interstellar/circumnuclear media in galaxies. On the basis of results obtained with Herschel far-infrared photometric surveys of distant galaxies and Spitzer and AKARI near- to mid-infrared spectroscopic observations of nearby galaxies, we estimate the numbers of the galaxies at redshift z > 0.5, which are expected to be detected in the polycyclic aromatic hydrocarbon features or dust continuum by a wide (10 deg2) or deep (1 deg2) blind survey, both for a given observation time of 600 h. As by-products of the wide blind survey, we also expect to detect debris disks, through the mid-infrared excess above the photospheric emission of nearby main-sequence stars, and we estimate their number. We demonstrate that the SPICA mid-infrared surveys will efficiently provide us with unprecedentedly large spectral samples, which can be studied further in the far-infrared with SPICA.
  • M. Yamagishi, H. Kaneda, D. Ishihara, S. Oyabu, T. Suzuki, T. Onaka, T. Nagayama, T. Umemoto, T. Minamidani, A. Nishimura, M. Matsuo, S. Fujita, Y. Tsuda, M. Kohno, S. Ohashi
    ASTROPHYSICAL JOURNAL 833(2) 2016年12月  査読有り
    We present Spitzer/IRS mid-infrared spectral maps of the Galactic star-forming region M17 as well as IRSF/SIRIUS Br gamma and Nobeyama 45 m/FOREST (CO)-C-13 (J = 1-0) maps. The spectra show prominent features due to polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, 11.3, 12.0, 12.7, 13.5, and 14.2 mu m. We find that the PAH emission features are bright in the region between the H II region traced by Br gamma and the molecular cloud traced by (CO)-C-13, supporting that the PAH emission originates mostly from photo-dissociation regions. Based on the spatially resolved Spitzer/IRS maps, we examine spatial variations of the PAH properties in detail. As a result, we find that the interband ratio of PAH 7.7 mu m/PAH 11.3 mu m varies locally near M17SW, but rather independently of the distance from the OB stars in M17, suggesting that the degree of PAH ionization is mainly controlled by local conditions rather than the global UV environments determined by the OB stars in M17. We also find that the interband ratios of the PAH 12.0 mu m, 12.7 mu m, 13.5 mu m, and 14.2 mu m features to the PAH. 11.3 mu m feature are high near the M17 center, which suggests structural changes of PAHs through processing due to intense UV radiation, producing abundant edgy irregular PAHs near the M17 center.
  • T. Wada, Y. Arai, S. Baba, M. Hanaoka, Y. Hattori, H. Ikeda, H. Kaneda, C. Kochi, A. Miyachi, K. Nagase, H. Nakaya, M. Ohno, S. Oyabu, T. Suzuki, S. Ukai, K. Watanabe, K. Yamamoto
    Journal of Low Temperature Physics 184(1-2) 217-224 2016年7月  査読有り
  • Koichi Nagase, Takehiko Wada, Hirokazu Ikeda, Yasuo Arai, Morifumi Ohno, Misaki Hanaoka, Hidehiro Kanada, Shinki Oyabu, Yasuki Hattori, Sota Ukai, Toyoaki Suzuki, Kentaroh Watanabe, Shunsuke Baba, Chihiro Kochi, Keita Yamamoto
    JOURNAL OF LOW TEMPERATURE PHYSICS 184(1-2) 449-453 2016年7月  査読有り
    We are developing a fully depleted silicon-on-insulator (FD-SOI) CMOS readout integrated circuit (ROIC) operated at temperatures below 4 K. Its application is planned for the readout circuit of high-impedance far-infrared detectors for astronomical observations. We designed a trans-impedance amplifier (TIA) using a CMOS operational amplifier (OPAMP) with FD-SOI technique. The TIA is optimized to readout signals from a germanium blocked impurity band (Ge BIB) detector which is highly sensitive to wavelengths of up to 200 m. For the first time, we demonstrated the FD-SOI CMOS OPAMP combined with the Ge BIB detector at 4.5 K. The result promises to solve issues faced by conventional cryogenic ROICs.
  • T. Suzuki, P. Khosropanah, M. L. Ridder, R. A. Hijmering, J. R. Gao, H. Akamatsu, L. Gottardi, J. van der Kuur, B. D. Jackson
    Journal of Low Temperature Physics 184(1-2) 52-59 2016年7月  査読有り筆頭著者
  • M. Hanaoka, H. Kaneda, S. Oyabu, M. Yamagishi, Y. Hattori, S. Ukai, K. Shichi, T. Wada, T. Suzuki, K. Watanabe, K. Nagase, S. Baba, C. Kochi
    Journal of Low Temperature Physics 184(1-2) 225-230 2016年  査読有り
  • Hidehiro Kaneda, Daisuke Ishihara, Shinki Oyabu, Mitsuyoshi Yamagishi, Takehiko Wada, Mitsunobu Kawada, Naoki Isobe, Kentaroh Asano, Toyoaki Suzuki, Takao Nakagawa, Hideo Matsuhara, Itsuki Sakon, Kohji Tsumura, Hiroshi Shibai, Taro Matsuo
    Proceedings of SPIE - The International Society for Optical Engineering 9904 2016年  
    SMI (SPICA Mid-infrared Instrument) is one of the two focal-plane scientific instruments planned for new SPICA, and the Japanese instrument proposed and managed by a university consortium in Japan. SMI covers the wavelength range of 12 to 36 μm, using the following three spectroscopic channels with unprecedentedly high sensitivities: low-resolution spectroscopy (LRS; R = 50 - 120, 17 - 36 μm), mid-resolution spectroscopy (MRS; R = 1300 - 2300, 18 - 36 μm), and high-resolution spectroscopy (HRS; R = 28000, 12 - 18 μm). The key functions of these channels are high-speed dustband mapping with LRS, high-sensitivity multi-purpose spectral mapping with MRS, and high-resolution molecular-gas spectroscopy with HRS. This paper describes the technical concept and scientific capabilities of SMI.
  • Yamagishi, M, Kaneda, H, Ishihara, D, Oyabu, S, Onaka, T, Shimonishi, T, Suzuki, T
    The Astrophysical Journal 807(29) 1-7 2015年7月25日  査読有り
  • H. Kaneda, D. Ishihara, K. Kobata, T. Kondo, S. Oyabu, R. Yamada, M. Yamagishi, T. Onaka, T. Suzuki
    PLANETARY AND SPACE SCIENCE 100 6-11 2014年10月  査読有り
    The infrared (IR) emission from interstellar dust grains is a powerful tool to trace star-formation activities in galaxies. Beyond such star-formation tracers, spectral information on polycyclic aromatic hydrocarbons (PAHs) and large grains, or even their photometric intensity ratios, has deep physical implications for understanding the properties of the interstellar medium. With the AKARI satellite launched in 2006, we have performed a systematic study of interstellar dust grains in various environments of galaxies including our Galaxy. Because of its unique capabilities, such as mid-/far-IR all-sky surveys and near-/far-IR spectroscopy, AKARI has provided new knowledge on the processing of dust, particularly carbonaceous grains including PAHs, in the interstellar space. For example, the near-IR spectroscopy has revealed structural changes of hydrocarbon grains in harsh environments of galaxies. In this paper, we focus on the properties of the PAH emission obtained by the AKARI mid-IR all-sky survey and near-IR spectroscopy. (C) 2014 Elsevier Ltd. All rights reserved.
  • T. Suzuki, P. Khosropanah, R. A. Hijmering, M. Ridder, M. Schoemans, H. Hoevers, J. R. Gao
    IEEE Transactions on Terahertz Science and Technology 4(2) 171-178 2014年3月  査読有り筆頭著者
  • Mitsuyoshi Yamagishi, Hidehiro Kaneda, Daisuke Ishihara, Shinki Oyabu, Takashi Onaka, Takashi Shimonishi, Toyoaki Suzuki, Young Chol Minh
    Astrophysical Journal Letters 773(2) 1-5 2013年8月20日  査読有り
    With AKARI, we obtain the spatially resolved near-infrared (NIR) (2.5-5.0 μm) spectra for the nearby starburst galaxy M 82. These spectra clearly show absorption features due to interstellar ices. Based on the spectra, we created the column density maps of H2O and CO2 ices. As a result, we find that the spatial distribution of H2O ice is significantly different from that of CO2 ice H2O ice is widely distributed, while CO2 ice is concentrated near the galactic center. Our result reveals for the first time variations in CO2/H 2O ice abundance ratio on a galactic scale, suggesting that an ice-forming interstellar environment changes within a galaxy. We discuss the cause of the spatial variations in the ice abundance ratio, utilizing spectral information on the hydrogen recombination Brα and Brβ lines and the polycyclic aromatic hydrocarbon 3.3 μm emission appearing in the AKARI NIR spectra. © 2013. The American Astronomical Society. All rights reserved.
  • T. Suzuki, H. Kaneda, T. Onaka
    Astronomy & Astrophysics 554 A8-A8 2013年6月  査読有り筆頭著者
  • T. Suzuki, H. Kaneda, T. Onaka
    Publications of The Korean Astronomical Society 27(4) 243-248 2012年9月16日  査読有り筆頭著者
  • Hidehiro Kaneda, Daisuke Ishihara, Koudai Kobata, Toru Kondo, Mitsuyoshi Yamagishi, Akiko Yasuda, Takashi Onaka, Itsuki Sakon, Toyoaki Suzuki
    Proceedings of the International Astronomical Union 8(292) 271-274 2012年8月  
    With AKARI, we have performed a systematic study of interstellar dust grains in various environments of galaxies. In many cases, the IR emission of dust is an important tool to trace star-forming activities in galaxies. However it is much more than just star-formation tracers. AKARI has revealed the detailed properties of dust grains in regions not relevant to star formation as well, some of which are found not to follow our old empirical knowledge. Because of its unique capabilities, such as near-and far-IR spectroscopy, and all-sky coverage, AKARI has provided new knowledge on the processing of carbonaceous grains including polycyclic aromatic hydrocarbons. We present the latest results obtained from our AKARI observations of the ISM in our Galaxy and nearby galaxies. © 2013 International Astronomical Union.
  • Toyoaki Suzuki, Takehiko Wada, Kazuyuki Hirose, Hironobu Makitsubo, Hidehiro Kaneda
    Publications of the Astronomical Society of the Pacific 124(918) 823-829 2012年8月  査読有り筆頭著者
  • Kondo Toru, Kaneda Hidehiro, Oyabu Shinki, Ishihara Daisuke, Mori Tatsuya, Yamagishi Mitsuyoshi, Onaka Takashi, Sakon Itsuki, Suzuki Toyoaki
    ASTROPHYSICAL JOURNAL LETTERS 751(1) 2012年5月20日  査読有り
  • M. Yamagishi, H. Kaneda, D. Ishihara, T. Kondo, T. Onaka, T. Suzuki, Y. C. Minh
    ASTRONOMY & ASTROPHYSICS 541 2012年5月  査読有り
    Aims. We investigate the properties of hydrocarbon grains in the galactic superwind of M 82. Methods. With AKARI, we performed near-infrared (2.5-4.5 mu m) spectroscopic observations of 34 regions in M 82 including its northern and southern halos. Results. Many of the spectra show strong emission at 3.3 mu m caused by polycyclic aromatic hydrocarbons (PAHs) and relatively weak features at 3.4-3.6 mu m caused by aliphatic hydrocarbons. In particular, we clearly detect the PAH 3.3 mu m emission and the 3.4-3.6 mu m features in halo regions, which are located at a distance of 2 kpc away from the galactic center. We find that the ratios of the 3.4-3.6 mu m features to the 3.3 mu m feature intensity significantly increase with distance from the galactic center, while the ratios of the 3.3 mu m feature to the AKARI 7 mu m band intensity do not. Conclusions. Our results clearly confirm the presence of small PAHs even in the harsh environment of the halo of M 82. The results also reveal that the aliphatic hydrocarbons emitting the 3.4-3.6 mu m features are unusually abundant in the halo, suggesting that small carbonaceous grains are produced by shattering of larger grains in the galactic superwind.
  • Hidehiro Kaneda, Takashi Onaka, Toyoaki Suzuki, Tatsuya Mori, Mitsuyoshi Yamagishi, Toru Kondo, Akiko Yasuda
    SPECTRAL ENERGY DISTRIBUTION OF GALAXIES (284) 254-+ 2012年  
    Many elliptical galaxies possess an appreciable amount of X-ray-emitting hot plasma, providing a harsh interstellar environment for the survival of dust grains and polycyclic aromatic hydrocarbons (PAHs). Despite such a hostile environment, it has been found that a significant fraction of X-ray elliptical galaxies contain a considerable amount of dust, which cannot be explained solely from replenishment by old stars. Some of them even show the presence of PAHs. We present the results of AKARI and Spitzer observations of dust and PAHs in X-ray elliptical galaxies. We investigate their possible origins and discuss the implications of their presence for the evolution of elliptical galaxies.
  • Toyoaki Suzuki, Hidehiro Kaneda, Takashi Onaka, Tetsu Kitayama
    SPECTRAL ENERGY DISTRIBUTION OF GALAXIES (284) 342-+ 2012年  
    Stephan's Quintet (SQ, HCG92) is a well studied compact group of galaxies with a disturbed intergalactic medium (IGM). An "intruder" galaxy NGC 7318b is currently colliding with the IGM at a relative velocity of 1000 km s(-1), causing a large-scale shock front. We observed SQ with the Far-Infrared Surveyor (FIS) aboard AKARI in four far-infrared (far-IR) bands at 65, 90, 140, and 160 mu m. The 160 mu m image clearly shows an additional peak of emission overlying structure extending in the North-South direction along the shock ridge seen in the 140 mu m band, and in H-2 and X-ray emission. Whereas most of the far-IR emission in the shocked region is from cold dust ( 20 K), the [CII]158 mu m emission - whose luminosity is comparable to that of the warm H2 gas - can significantly contribute to the single peak emission in the 160 mu m, band. We conclude that the [CII] line emission comes from the warm H-2 gas in the shock. Our result represents the first detection of shock-excited [CH] line emission.
  • Norio Ikeda, Yoshimi Kitamura, Satoshi Takita, Munetaka Ueno, Toyoaki Suzuki, Akiko Kawamura, Hidehiro Kaneda
    ASTROPHYSICAL JOURNAL 745(1) 2012年1月  
    We have carried out far-infrared imaging observations toward the Chamaeleon star-forming region by the Far-Infrared Surveyor (FIS) on board the AKARI satellite. The AKARI images cover a total area of 33.79 deg(2), corresponding to 210 pc(2) at the distance to the source. Using the FIS bands of 65-160 mu m and the COBE/DIRBE bands of 60-240 mu m, we constructed column density maps of cold (11.7 K) and warm (22.1 K) dust components with a linear resolution of 0.04 pc. On the basis of their spatial distributions and physical properties, we interpret that the cold component corresponds to the molecular clouds and the warm one the cold H I clouds, which are thought to be in a transient phase between atomic and molecular media. The warm component is shown to be uniformly distributed at a large spatial scale of similar to 50 pc, while a several pc-scale gradient along the east-west direction is found in the distribution of the cold component. The former is consistent with a formation scenario of the cold H I clouds through the thermal instability in the warm neutral medium triggered by a 100 pc scale supernova explosion. This scenario, however, cannot produce the latter, several pc-scale gradient in molecular cloud mass. We conclude that the gravitational fragmentation of the cold Hi cloud likely created the molecular clouds with spatial scale as small as several pc.
  • Hidehiro Kaneda, Takehiko Wada, Shinki Oyabu, Ryoko Kano, Yuichi Kiriyama, Yasuki Hattori, Toyoaki Suzuki, Kensuke Ide, Masahiro Kato, Kentaroh Watanabe
    JAPANESE JOURNAL OF APPLIED PHYSICS 50(6) 2011年6月  査読有り
    We have evaluated the electrical and photoconductive properties of a Ge p(+)-i junction device, fabricated by surface-activated wafer bonding (SAB) technology, at temperatures of 1.8-5 K. The p(+)-i junction consists of two bonded layers, Ge heavily doped with Ga at a concentration of 1 x 10(16) cm(-3) and non-doped intrinsic Ge. The bonded Ge wafer was diced to a 1-mm cubic test element having two layers of thickness 0.5 mm and two facing electrodes. We measured the current-voltage characteristics of the device at 1.8-5 K, and its photoresponses against stepped illumination with far-infrared light at 1.8 K. The device shows the expected cryogenic performance in terms of electrical and photoconductive properties, demonstrating the promising applicability of SAB-processed Ge p(+)-i junction devices in blocked-impurity-band-type Ge detectors. (C) 2011 The Japan Society of Applied Physics
  • Toyoaki Suzuki, Hidehiro Kaneda, Takashi Onaka, Tetsu Kitayama
    The Astrophysical Journal 731(1) L12-L12 2011年4月10日  査読有り筆頭著者
  • Mitsuyoshi Yamagishi, Hidehiro Kaneda, Daisuke Ishihara, Shinki Oyabu, Takashi Onaka, Takashi Shimonishi, Toyoaki Suzuki
    ASTROPHYSICAL JOURNAL LETTERS 731(1) 1-5 2011年4月  査読有り
    We present the spatially resolved near-infrared (2.5-5.0 mu m) spectra of the edge-on starburst galaxy NGC 253 obtained with the Infrared Camera on board AKARI. Near the center of the galaxy, we clearly detect the absorption features of interstellar ices (H2O: 3.05 mu m, CO2: 4.27 mu m, and XCN: 4.62 mu m) and the emission of polycyclic aromatic hydrocarbons (PAHs) at 3.29 mu m and the hydrogen recombination line Br alpha at 4.05 mu m. We find that the distributions of the ices differ from those of the PAH and gas. We calculate the column densities of the ices and derive the abundance ratios of N(CO2)/N(H2O) = 0.17 +/- 0.05. They are similar to those obtained around the massive young stellar objects in our Galaxy (0.17 +/- 0.03), although a much stronger interstellar radiation field and higher dust temperature are expected near the center of NGC 253.
  • T. Suzuki, H. Kaneda, T. Onaka, T. Nakagawa, H. Shibai
    Astronomy and Astrophysics 521(5) A48-A48 2010年10月  査読有り筆頭著者
    Aims. We assess the relationships between the surface densities of the gas and star formation rate (SFR) within spiral arms of the nearby late-type spiral galaxies M 81 and M 101. By analyzing these relationships locally, we empirically derive a kiloparsec scale Kennicutt-Schmidt Law (Σ \propto Σ ). Methods. Both M 81 and M 101 were observed with the Far-Infrared Surveyor (FIS) aboard AKARI in four far-infrared bands at 65, 90, 140, and 160 μm. Results. The spectral energy distributions of the whole galaxies show the presence of the cold dust component (T ∼ 20 K) in addition to the warm dust component (T ∼ 60 K). We deconvolved the cold and warm dust emission components spatially by making the best use of the multi-band photometric capability of the FIS. The cold and warm dust components show power-law correlations in various regions, which can be converted into the gas mass and the SFR, respectively. We find a power-law correlation between the gas and SFR surface densities with significant differences in the power-law index N between giant H ii regions (N = 1.0 ± 0.5) and spiral arms (N = 2.2 ± 0.2) in M 101. The power-law index for spiral arms in M 81 is similar (N = 1.9 ± 0.4) to that of spiral arms in M 101. Conclusions. The power-law index is not always constant within a galaxy. The difference can be attributed to the difference in the star formation processes on a kiloparsec scale. N ≈2 seen in the spiral arms in M 81 and M 101 supports the scenario of star formation triggered by cloud-cloud collisions enhanced by a spiral density wave, while N ≈ 1 derived in giant H ii regions in M 101 suggests the star formation induced by the Parker instability triggered by high-velocity H i gas infall. The present method can be applied to a large galaxy sample for which the AKARI All Sky Survey provides the same 4 far-infrared band data. © 2010 ESO. SFR gas C W N
  • H. Kaneda, T. Suzuki, T. Onaka, I. Takase, M. Yamagishi, D. Ishihara, I. Sakon
    HIGHLIGHTS OF ASTRONOMY, VOL 15 15 414-414 2010年  
    We have observed 57 nearby galaxies in the far-infrared with the Far-Infrared Surveyor on AKARI to study the properties of dust in various environments.
  • Hidehiro Kaneda, Takashi Onaka, Itsuki Sakon, Tetsu Kitayama, Yoko Okada, Toyoaki Suzuki, Daisuke Ishihara, Mitsuyoshi Yamagishi
    Astrophysical Journal Letters 716(2) L161-L165 2010年  
    Spitzer and AKARI observations have found that polycyclic aromatic hydrocarbons (PAHs) are present in nearby elliptical galaxies, but their spatial distributions are still unknown. In order to investigate their distributions, we performed deep spectral mapping observations of the PAH-detected elliptical galaxy NGC 4589, a merger remnant with a minor-axis optical dust lane. As a result, we obtain clear evidence that the PAH 11.3 μm emission comes predominantly from the dust lane of the galaxy. We also detect molecular hydrogen line emissions from the dust lane. The PAH 17 μm emission is distributed differently from the PAH 11.3 μm emission, and more similarly to the dust continuum emission. From their distinctive distributions, we suggest that the PAHs responsible for the 11.3 μm feature are secondary products through the evolution of the interstellar medium brought in by the merger. © 2010. The American Astronomical Society. All rights reserved.
  • Mai Shirahata, Shuji Matsuura, Sunao Hasegawa, Takafumi Ootsubo, Sin'itirou Makiuti, Issei Yamamura, Takao Nakagawa, Mitsunobu Kawada, Hidehiro Kaneda, Hiroshi Shibai, Yasuo Doi, Toyoaki Suzuki, Thomas Mueller, Martin Cohen
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 61(4) 737-750 2009年8月  
    We present the characterization and calibration of the Slow-Scan observation mode of the Far-Infrared Surveyor (FIS) onboard the AKARI satellite. The FIS, one of the two focal-plane instruments on AKARI, has four photometric bands between 50-180 mu m with two types of Ge:Ga array detectors. In addition to the All-Sky Survey, FIS has also taken detailed far-infrared images of selected targets by using the Slow-Scan mode. The sensitivity of the Slow-Scan mode is one to two orders of magnitude better than that of the All-Sky Survey, because the exposure time on a targeted source is much longer. The point spread functions (PSFs) were obtained by observing several bright point-like objects, such as asteroids, stars, and galaxies. The derived full widths at the half maximum (FWHMs) are similar to 30 '' for the two shorter wavelength bands and similar to 40 '' for the two longer wavelength bands, being consistent with those expected by optical simulation, although a certain amount of excess is seen in the tails of the PSFs. A flux calibration was performed by observations of well-established photometric calibration standards (asteroids and stars) over a wide range of fluxes. After establishing the method of aperture photometry, the photometric accuracy for point-sources is better than +/- 15% in all of the bands, expect for the longest wavelength.

MISC

 31

講演・口頭発表等

 43

所属学協会

 1

共同研究・競争的資金等の研究課題

 9