Updated on 2024/03/22

写真a

 
KOKUSHO Takuma
 
Organization
Graduate School of Science Lecturer
Graduate School
Graduate School of Science
Undergraduate School
School of Science Department of Physics
Title
Lecturer

Degree 1

  1. 博士(理学) ( 2017.3   名古屋大学 ) 

Research Areas 2

  1. Natural Science / Astronomy

  2. Natural Science / Astronomy

Current Research Project and SDGs 2

  1. Development of a new interferometer for evaluation of free-form mirrors at cryogenic temperatures

  2. Development of the IRSF spectrometer for near-infrared spectral mapping of the Large Magellanic Cloud

Research History 1

  1. Nagoya University

    2017.4

Education 1

  1. Nagoya University   Graduate School, Division of Natural Science

    - 2017.3

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    Country: Japan

Professional Memberships 1

  1. 日本天文学会

 

Papers 44

  1. Properties of Star Formation of the Large Magellanic Cloud As Probed by Young Stellar Objects Reviewed

    Takuma Kokusho, Hiroki Torii, Hidehiro Kaneda, Yasuo Fukui, Kengo Tachihara

    The Astrophysical Journal   Vol. 953 ( 1 ) page: 104 - 104   2023.8

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    Abstract

    We perform a systematic study of the evolutionary stages and stellar masses of young stellar objects (YSOs) in the Large Magellanic Cloud (LMC) to investigate the properties of star formation in the galaxy. There are 4825 sources in our YSO sample, which are constructed by combining the previous studies identifying YSOs in the LMC. Spectral energy distributions of the YSOs from optical to infrared wavelengths were fitted with a model consisting of stellar, polycyclic aromatic hydrocarbon, and dust emissions. We utilize the stellar-to-dust luminosity ratios thus derived to study the evolutionary stages of the sources; younger YSOs are expected to show lower stellar-to-dust luminosity ratios. We find that most of the YSOs are associated with the interstellar gas across the galaxy, which are younger with more gas, suggesting that more recent star formation is associated with larger amounts of the interstellar medium (ISM). N157 shows a hint of higher stellar-to-dust luminosity ratios between active star-forming regions in the LMC, suggesting that recent star formation in N157 is possibly in later evolutionary stages. We also find that the stellar mass function tends to be bottom-heavy in supergiant shells (SGSs), indicating that gas compression by SGSs may be ineffective in compressing the ISM enough to trigger massive star formation. There is no significant difference in the stellar mass function between YSOs likely associated with the interface between colliding SGSs and those with a single SGS, suggesting that gas compression by collisions between SGSs may also be ineffective for massive star formation.

    DOI: 10.3847/1538-4357/ace10e

    Web of Science

    Other Link: https://iopscience.iop.org/article/10.3847/1538-4357/ace10e/pdf

  2. Spitzer/IRS Full Spectral Modeling to Characterize Mineralogical Properties of Silicate Dust in Heavily Obscured AGNs Reviewed

    T. Tsuchikawa, H. Kaneda, S. Oyabu, T. Kokusho, H. Kobayashi, Y. Toba

    The Astrophysical Journal   Vol. 941 ( 1 ) page: 50 - 50   2022.12

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    Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    Abstract

    Mid-infrared silicate dust bands observed in heavily obscured active galactic nuclei (AGNs) include information on the mineralogical properties of silicate dust. We aim to investigate the mineralogical picture of the circumnuclear region of heavily obscured AGNs to reveal obscured AGN activities through the picture. In our previous study, we investigated the properties of silicate dust in heavily obscured AGNs, focusing on the mineralogical composition and the crystallinity with Spitzer/IRS 5.3–12 μm spectra. In this study, we model the full-range Spitzer/IRS 5–30 μm spectra of 98 heavily obscured AGNs using a one-dimensional radiative transfer calculation with four dust species in order to evaluate wider ranges of the properties of silicate dust more reliably. Comparing fitting results between four dust models with different sizes and porosities, 95 out of the 98 galaxies prefer a porous silicate dust model without micron-sized large grains. The pyroxene mass fraction and the crystallinity are overall consistent with—but significantly different from—the previous results for the individual galaxies. The pyroxene-poor composition, small dust size, and high porosity are similar to newly formed dust around mass-loss stars as seen in our Galaxy, which presumably originates from the recent circumnuclear starburst activity. The high crystallinity on average suggests dust processing induced by AGN activities.

    DOI: 10.3847/1538-4357/ac9b23

    Web of Science

    Other Link: https://iopscience.iop.org/article/10.3847/1538-4357/ac9b23/pdf

  3. Spitzer/IRS full spectral modeling to characterize mineralogical properties of silicate dust in heavily obscured AGNs Reviewed

    Tsuchikawa, T., Kaneda, H., Oyabu, S., Kokusho, T., Kobayashi, H., Toba, Y.

    Astronomy & Astrophysics     2022.10

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    Language:English  

  4. Three-dimensional geometry and dust/gas ratios in massive star-forming regions over the entire LMC as revealed by the IRSF/SIRIUS survey Reviewed

    Takuya Furuta, Hidehiro Kaneda, Takuma Kokusho, Yasushi Nakajima, Yasuo Fukui, Kisetsu Tsuge

    Publications of the Astronomical Society of Japan   Vol. 74 ( 3 ) page: 639 - 655   2022.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    Abstract

    We derive the entire dust extinction (AV) map for the Large Magellanic Cloud (LMC) estimated from the color excess at near-infrared wavelengths. Using the percentile method we recently adopted to evaluate AV distribution along the line of sight, we derive three-dimensional (3D) AV maps of the three massive star-forming regions of N44, N79, and N11 based on the IRSF/SIRIUS point source catalog. The 3D AV maps are compared with the hydrogen column densities N(H) of three different velocity components where one is of the LMC disk velocity and the other two are of velocities lower than the disk velocity. As a result, we obtain a 3D dust geometry suggesting that gas collision is ongoing between the different velocity components. We also find differences in the timing of the gas collision between the massive star-forming regions, which indicates that the gas collision in N44, N79, and N11 occurred later than that in 30 Doradus. In addition, a difference of a factor of two in AV/N(H) is found between the velocity components for N44, while a significant difference is not found for N79 and N11. From the 3D geometry and AV/N(H) in each star-forming region, we suggest that the massive star formation in N44 was induced by an external trigger of tidal interaction between the LMC and the Small Magellanic Cloud, while that in N79 and N11 is likely to have been induced by internal triggers such as gas converging from the galactic spiral arm and expansion of a supershell, although the possibility of tidal interaction cannot be ruled out.

    DOI: 10.1093/pasj/psac025

    Web of Science

  5. Three-dimensional geometry and dust/gas ratios in massive star forming regions over the entire LMC as revealed by IRSF/SIRIUS survey Reviewed

    Furuta, Takuya ; Kaneda, Hidehiro ; Kokusho, Takuma ; Nakajima, Yasushi ; Fukui, Yasuo ; Tsuge, Kisetsu

    Publications of the Astronomical Society of Japan     2022.3

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    Language:English  

  6. Infrared Absorption and Its Sources of CdZnTe at Cryogenic Temperature Reviewed

    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   Vol. 51 ( 2 ) page: 564 - 576   2022.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    To reveal the causes of infrared absorption in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of p-type low-resistivity ($$\sim 10^2~ \Omega \mathrm{cm}$$) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four wavelength bands ($$\lambda =6.45$$, 10.6, 11.6, 15.1$$~\mu $$m) over the temperature range of $$T=8.6$$-300 K with an originally developed system. The CdZnTe absorption coefficient was measured to be $$\alpha =0.3$$-0.5 $$\mathrm{cm}^{-1}$$ at $$T=300$$ K and $$\alpha =0.4$$-0.9 $$\mathrm{cm}^{-1}$$ at $$T=8.6$$ K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at $$T=150$$-300 K and that due to trapped-holes at $$T<50$$ K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.

    DOI: 10.1007/s11664-021-09361-1

    Web of Science

    Other Link: https://link.springer.com/article/10.1007/s11664-021-09361-1/fulltext.html

  7. Investigation of the Physical Origin of Overionized Recombining Plasma in the Supernova Remnant IC 443 with XMM-Newton Reviewed

    Hiromichi Okon, Takaaki Tanaka, Hiroyuki Uchida, Takeshi Go Tsuru, Masumichi Seta, Takuma Kokusho, Randall K. Smith

    The Astrophysical Journal   Vol. 921 ( 2 ) page: 99 - 99   2021.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    DOI: 10.3847/1538-4357/ac1e2c

    Web of Science

    Other Link: https://iopscience.iop.org/article/10.3847/1538-4357/ac1e2c/pdf

  8. Three-dimensional dust geometry of the LMC H I ridge region as revealed by the IRSF/SIRIUS survey Reviewed

    Furuta, Takuya ; Kaneda, Hidehiro ; Kokusho, Takuma ; Nakajima, Yasushi ; Fukui, Yasuo ; Tsuge, Kisetsu

    Publications of the Astronomical Society of Japan   Vol. 73 ( 4 ) page: 864 - 879   2021.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/pasj/psab052

    Web of Science

  9. Three-dimensional dust geometry of the LMC H I ridge region as revealed by the IRSF/SIRIUS survey Reviewed

    Furuta, Takuya, Kaneda, Hidehiro, Kokusho, Takuma, Nakajima, Yasushi, Fukui, Yasuo, Tsuge, Kisetsu

    Publications of the Astronomical Society of Japan   Vol. 73 ( 4 ) page: 864 - 879   2021.8

  10. A systematic study of silicate absorption features in heavily obscured AGNs observed by Spitzer/IRS Reviewed

    Tsuchikawa T., Kaneda H., Oyabu S., Kokusho T., Kobayashi H., Yamagishi M., Toba Y.

    ASTRONOMY & ASTROPHYSICS   Vol. 651   2021.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1051/0004-6361/202140483

    Web of Science

  11. A systematic study of silicate absorption features in heavily obscured AGNs observed by Spitzer/IRS Reviewed

    Tsuchikawa, T, Kaneda, H, Oyabu, S, Kokusho, T, Kobayashi, H, Yamagishi, M, Toba, Y

    Astronomy & Astrophysics   Vol. 651 ( A117 )   2021.7

  12. SPICA Mid-infrared Instrument (SMI): The latest design and specifications

    Takehiko Wada, Hidehiro Kaneda, Takuma Kokusho, Toyoaki Suzuki, Kumiko Morihana, Takurou Tsuchikawa, Yuki Kuroda, Daichi Ishikawa, Shinki Oyabu, Naoki Isobe, Daisuke Ishihara, Hideo Matsuhara, Koichi Nagase, Takao Nakagawa, Takafumi Ootsubo, Mitsuyoshi Yamagishi, Hiroshi Maeshima, Shunsuke Onishi, Kosei Matsumoto, Satoshi Itoh, Mizuho Uchiyama, Ryan Lau, Hiromichi Ebihara, Hanae Inami, Koji Kawabata, Yasumasa Kasaba, Takeshi Sakanoi, Yoshifusa Ita, Masayuki Akiyama, Itsuki Sakon, Takafumi Kamizuka, Takashi Miyata, Kohji Tsumura, Masato Naruse, Youichi Ohyama, Shiang-Yu Wang, Hiroshi Shibai

    Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave   Vol. 11443   2021

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:SPIE  

    SMI (SPICA Mid-infrared Instrument) is one of the three focal-plane science instruments for SPICA. SMI is the Japanese-led instrument proposed and managed by a university consortium. SMI covers the wavelength range from 10 to 36 mu m with four separate channels: the low-resolution (R = 60 - 160) spectroscopy function for 17 - 36 mu m, the broad-band (R = 5) imaging function at 34 mu m, the mid-resolution (R = 1400 - 2600) spectroscopy function for 18 - 36 mu m, and the high-resolution (R = 29000) spectroscopy function for 10 - 18 mu m. In this presentation, we will show the latest design and specifications of SMI as a result of feasibility studies.

    DOI: 10.1117/12.2561157

    Web of Science

  13. Hydrogen recombination near-infrared line mapping of Centaurus A with IRSF/SIRIUS Reviewed

    Risako Katayama, Hidehiro Kaneda, Takuma Kokusho, Kumiko Morihana, Toyoaki Suzuki, Shinki Oyabu, Mitsuyoshi Yamagishi, Takuro Tsuchikawa

    Publications of the Astronomical Society of Japan   Vol. 72 ( 5 )   2020.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    <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.

    DOI: 10.1093/pasj/psaa081

    Web of Science

  14. Hydrogen recombination near-infrared line mapping of Centaurus A with IRSF/SIRIUS (vol 72, pg 88, 2020) Reviewed

    Katayama Risako, Kaneda Hidehiro, Kokusho Takuma, Morihana Kumiko, Suzuki Toyoaki, Oyabu Shinki, Yamagishi Mitsuyoshi, Tsuchikawa Takuro

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   Vol. 72 ( 5 )   2020.10

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    Language:English  

    DOI: 10.1093/pasj/psaa094

    Web of Science

  15. Near-infrared [Fe II] and H2 Line Mapping of the Supernova Remnant IC 443 with the IRSF/SIRIUS Reviewed

    Takuma Kokusho, Hiroki Torii, Takahiro Nagayama, Hidehiro Kaneda, Hidetoshi Sano, Daisuke Ishihara, Takashi Onaka

    The Astrophysical Journal   Vol. 899 ( 1 ) page: 49 - 49   2020.8

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Astronomical Society  

    DOI: 10.3847/1538-4357/ab9cb3

    Web of Science

    Other Link: https://iopscience.iop.org/article/10.3847/1538-4357/ab9cb3

  16. Pixel-based Spectral Characterization of Mid-infrared Si Array Detectors for Astronomical Observations in Space Reviewed

    Takuro Tsuchikawa, Hidehiro Kaneda, Daisuke Ishihara, Takuma Kokusho, Takehiko Wada

    Publications of the Astronomical Society of the Pacific   Vol. 132 ( 1013 ) page: 074502 - 074502   2020.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    DOI: 10.1088/1538-3873/ab8aa8

    Web of Science

    Other Link: https://iopscience.iop.org/article/10.1088/1538-3873/ab8aa8

  17. A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel. II. Spatial distributions of dust components around the bubbles Reviewed

    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   Vol. 72 ( 1 )   2020.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    <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.

    DOI: 10.1093/pasj/psz123

    Web of Science

  18. Transmittance measurement of low/high-resistivity of CdZnTe at cryogenic temperature for material selection of the immersion grating of SPICA SMI

    Hiroshi Maeshima, Kosei Matsumoto, Yasuhiro Hirahara, Takao Nakagawa, Takehiko Wada, Koichi Nagase, Shinki Oyabu, Toyoaki Suzuki, Takuma Kokusho, Hidehiro Kaneda, Ryota Ito, Daichi Ishikawa

    Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV   Vol. 11451   2020

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:SPIE  

    We measured the transmittance of low-resistivity (∼10 2 ωcm) and high-resistivity (> 10 10 ωcm) CdZnTe, which are candidates for Immersion grating (IG) in 10-18μm wavelength, at cryogenic temperature. IG is a compact diffraction grating and we are developing a cryogenically operated 10-18μm IG for SMI/HR (SPICA Mid-Infrared Instrument / High-Resolution spectrometer) of SPICA (SPace Infrared telescope for Cosmology and Astrophysics) We performed two experiments: Transmittance measurement with a convergent light Fourier transform spectrometer, and with a collimated lamp beam system. Our result shows that the low-resistivity CdZnTe has large absorption (> 0.5 cm {-1}) and the high-resistivity CdZnTe has low absorption (< 0.1 cm {-1}) at 8.5K at 10-18 μm. The high-resistivity CdZnTe is promising as an IG material although higher precision measurement is needed to determine whether it meets the absorption coefficient requirement (< 0.01 cm {-1}) at cryogenic temperature.

    DOI: 10.1117/12.2562042

    Web of Science

    Scopus

  19. Extinction and dust/gas ratio in the H i ridge region of the LMC based on the IRSF/SIRIUS near-infrared survey Reviewed

    Takuya Furuta, Hidehiro Kaneda, Takuma Kokusho, Daisuke Ishihara, Yasushi Nakajima, Yasuo Fukui, Kisetsu Tsuge

    Publications of the Astronomical Society of Japan   Vol. 71 ( 5 )   2019.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    <title>ABSTRACT</title>
    We present a dust extinction AV map of the Large Magellanic Cloud (LMC) in the H i ridge region using the InfraRed Survey Facility (IRSF) near-infrared (IR) data, and compare the AV map with the total hydrogen column density N(H) maps derived from the CO and H i observations. In the LMC H i ridge region, the two-velocity H i components (plus an intermediate velocity component) are identified, and the young massive star cluster is possibly formed by collision between them. In addition, one of the components is suggested to be an inflow gas from the Small Magellanic Cloud (SMC) which is expected to have even lower metallicity gas (Fukui et al. 2017, PASJ, 69, L5). To evaluate dust/gas ratios in the H i ridge region in detail, we derive the AV map from the near-IR color excess of the IRSF data updated with the latest calibration, and fit the resultant AV map with a combination of the N(H) maps of the different velocity components to decompose it successfully into the three components. As a result, we find difference by a factor of 2 in AV/N(H) between the components. In additon, the CO-to-H2 conversion factor also indicates difference between the components, implying a difference in the metallicity. Our results are likely to support the scenario that the gas in the LMC H i ridge region is contaminated with an inflow gas from the SMC with a geometry consistent with the on-going collision between the two-velocity components.

    DOI: 10.1093/pasj/psz078

    Web of Science

  20. Near- to mid-infrared spectroscopy of the heavily obscured AGN LEDA 1712304 with AKARI/IRC Reviewed

    T. Tsuchikawa, H. Kaneda, S. Oyabu, T. Kokusho, K. Morihana, H. Kobayashi, M. Yamagishi, Y. Toba

    Astronomy & Astrophysics   Vol. 626   page: A130 - A130   2019.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:EDP Sciences  

    <italic>Context</italic>. Although heavily obscured active galactic nuclei (AGNs) have been found by many observational studies, the properties of the surrounding dust are poorly understood. Using AKARI/IRC spectroscopy, we discovered a new heavily obscured AGN in LEDA 1712304 which shows a deep spectral absorption feature due to silicate dust.


    <italic>Aims.</italic> We study the infrared (IR) spectral properties of circumnuclear silicate dust in LEDA 1712304.


    <italic>Methods.</italic> We performed IR spectral fitting, considering silicate dust properties such as composition, porosity, size, and crystallinity. Spectral energy distribution fitting was also performed on the flux densities in the UV to submillimeter range to investigate the global spectral properties.


    <italic>Results.</italic> The best-fit model indicates 0.1 <italic>μ</italic>m-sized porous amorphous olivine (Mg<sub>2<italic>x</italic></sub>Fe<sub>2−2<italic>x</italic></sub>SiO<sub>4</sub>; <italic>x</italic> = 0.4) with 4% crystalline pyroxene. The optical depth is <italic>τ</italic><sub>sil</sub> ∼ 2.3, while the total IR luminosity and stellar mass are estimated to be <italic>L</italic><sub>IR</sub> = (5 ± 1)×10<sup>10</sup> <italic>L</italic><sub>⊙</sub> and <italic>M</italic><sub>star</sub> = (2.7 ± 0.8)×10<sup>9</sup> <italic>M</italic><sub>⊙</sub>, respectively. In such low <italic>L</italic><sub>IR</sub> and <italic>M</italic><sub>star</sub> ranges, there are few galaxies that show such a large <italic>τ</italic><sub>sil</sub>.


    <italic>Conclusion.</italic> The silicate dust in the AGN torus of LEDA 1712304 has properties that are notably similar to those in other AGNs overall, but slightly different in the wing shape of the absorption profile. The porosity of the silicate dust suggests dust coagulation or processing in the circumnuclear environments, while the crystallinity suggests that the silicate dust is relatively fresh.

    DOI: 10.1051/0004-6361/201935483

    Web of Science

  21. Dust properties in the cold and hot gas phases of the ATLAS3D early-type galaxies as revealed by AKARI Reviewed

    T. Kokusho, H. Kaneda, M. Bureau, T. Suzuki, K. Murata, A. Kondo, M. Yamagishi, T. Tsuchikawa, T. Furuta

    Astronomy & Astrophysics   Vol. 622   page: A87 - A87   2019.1

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:EDP Sciences  

    <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 ATLAS<sup>3D</sup> 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.

    DOI: 10.1051/0004-6361/201833911

    Web of Science

  22. A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel Reviewed

    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   Vol. 71 ( 1 )   2019.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    DOI: 10.1093/pasj/psy126

    Web of Science

    arXiv

  23. Enhanced dust emissivity power-law index along the western H α filament of NGC 1569 Reviewed

    T Suzuki, H Kaneda, T Onaka, M Yamagishi, D Ishihara, T Kokusho, T Tsuchikawa

    Monthly Notices of the Royal Astronomical Society   Vol. 477 ( 3 ) page: 3065 - 3075   2018.7

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    DOI: 10.1093/mnras/sty800

    Web of Science

    Scopus

    arXiv

  24. SPICA mid-infrared instrument (SMI): conceptual design and feasibility studies

    Kaneda, Hidehiro; Ishihara, Daisuke; Oyabu, Shinki; Fukagawa, Misato; Kokusho, Takuma; Suzuki, Toyoaki; Furuta, Takuya; Tsuchikawa, Takurou; Wada, Takehiko; Isobe, Naoki; Kawada, Mitsunobu; Kwon, Jungmi; Matsuhara, Hideo; Nagase, Koichi; Nakagawa, Takao; Ootsubo, Takafumi; Yamagishi, Mitsuyoshi; Sakon, Itsuki; Tsumura, Kohji; Shibai, Hiroshi

    Proceedings of the SPIE   Vol. 10698   2018.7

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    DOI: 10.1117/12.2313093

  25. Processing of hydrocarbon dust in star-forming galaxies revealed with AKAR

    Kondo, Akino; Kaneda, Hidehiro; Fukagawa, Misato; Suzuki, Toyoaki; Murata, Katsuhiro L.; Kokusho, Takuma; Oyabu, Shinki

    Proceedings of The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life     2018.3

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  26. A systematic study of Galactic infrared bubbles along the whole Galactic plane with the AKARI all-sky surveys

    Hanaoka, Misaki; Kaneda, Hidehiro; Suzuki, Toyoaki; Kokusho, Takuma; Oyabu, Shinki; Ishihara, Daisuke

    Proceedings of The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life     2018.3

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  27. Development of the near-infrared spectrometer for the IRSF telescope

    Furuta, Takuya; Nagayama, Takahiro; Kaneda, Hidehiro; Kokusho, Takuma; Yamaguchi, Yuta; Tsuchikawa, Takuro; Fukagawa, Misato; Ishihara, Daisuke

    Proceedings of The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life     2018.3

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  28. A multiwavelength study of the ISM and star formation in early-type galaxies

    Kokusho, Takuma; Kaneda, Hidehiro; Bureau, Martin; Suzuki, Toyoaki; Murata, Katsuhiro; Kondo, Akino; Yamagishi, Mitsuyoshi

    Proceedings of The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life     2018.3

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  29. A multiwavelength study of the ISM and star formation in early-type galaxies

    Kokusho, Takuma, Kaneda, Hidehiro, Bureau, Martin, Suzuki, Toyoaki, Murata, Katsuhiro, Kondo, Akino, Yamagishi, Mitsuyoshi

    The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life. Edited by Takafumi Ootsubo, Issei Yamamura, Kazumi Murata and Takashi Onaka.     page: 127 - 130   2018.3

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

  30. SPICA Mid-infrared Instrument (SMI): conceptual design and feasibility studies

    Kaneda Hidehiro, Ishihara Daisuke, Oyabu Shinki, Fukagawa Misato, Kokusho Takuma, Suzuki Toyoaki, Furuta Takuya, Tsuchikawa Takurou, Wada Takehiko, Isobe Naoki, Kawada Mitsunobu, Kwon Jungmi, Matsuhara Hideo, Nagase Koichi, Nakagawa Takao, Ootsubo Takafumi, Yamagishi Mitsuyoshi, Sakon Itsuki, Tsumura Kohji, Shibai Hiroshi

    SPACE TELESCOPES AND INSTRUMENTATION 2018: OPTICAL, INFRARED, AND MILLIMETER WAVE   Vol. 10698   2018

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1117/12.2313093

    Web of Science

  31. A relationship of polycyclic aromatic hydrocarbon features with galaxy merger in star-forming galaxies at z &lt; 0.2 Reviewed

    Katsuhiro L. Murata, Rika Yamada, Shinki Oyabu, Hidehiro Kaneda, Daisuke Ishihara, Mitsuyoshi Yamagishi, Takuma Kokusho, Tsutomu T. Takeuchi

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   Vol. 472 ( 1 ) page: 39 - 50   2017.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:OXFORD UNIV PRESS  

    Using the AKARI, Wide-field Infrared Survey Explorer (WISE), Infrared Astronomical Satellite (IRAS), Sloan Digital Sky Survey (SDSS) and Hubble Space Telescope (HST) data, we investigated the relation of polycyclic aromatic hydrocarbon (PAH) mass (M-PAH), very small grain mass (M-VSG), big grain mass (M-BG) and stellar mass (M-star) with galaxy merger for 55 star-forming galaxies at redshift z &lt; 0.2. Using the SDSS image at z &lt; 0.1 and the HST image at z &gt; 0.1, we divided the galaxies into merger galaxies and non-merger galaxies with the morphological parameter asymmetry A, and quantified merging stages of galaxies based on the morphological indicators, the second-order momentum of the brightest 20 per cent region M-20 and the Gini coefficient. We find that M-PAH/M-BG of merger galaxies tend to be lower than that of non-merger galaxies and there are no systematic differences of M-VSG/M-BG and M-BG/M-star between merger galaxies and non-merger galaxies. We find that galaxies with very low M-PAH/M-BG seem to be merger galaxies at late stages. These results suggest that PAHs are partly destroyed at late stages of merging processes. Furthermore, we investigated MPAH/MBG variations in radiation field intensity strength G(0) and the emission line ratio of [O I] lambda 6300/H alpha that is a shock tracer for merger galaxies and find that M-PAH/M-BG decreases with increasing both G(0) and [O I]/H alpha. PAH destruction is likely to be caused by two processes: strong radiation fields and large-scale shocks during merging processes of galaxies.

    DOI: 10.1093/mnras/stx1902

    Web of Science

  32. A star formation study of the ATLAS(3D) early-type galaxies with the AKARI all-sky survey Reviewed

    T. Kokusho, H. Kaneda, M. Bureau, T. Suzuki, K. Murata, A. Kondo, M. Yamagishi

    ASTRONOMY & ASTROPHYSICS   Vol. 605   2017.9

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    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.

    DOI: 10.1051/0004-6361/201630158

    Web of Science

    arXiv

  33. A SYSTEMATIC STUDY OF DUST IN EARLY-TYPE GALAXIES WITH AKARI Reviewed

    Takuma Kokusho, Hidehiro Kaneda, Toru Kondo, Shinki Oyabu, Mitsuyoshi Yamagishi, Katsuhiro Murata

    Publications of The Korean Astronomical Society   Vol. 32 ( 1 ) page: 151 - 153   2017.3

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Korean Astronomical Society  

    DOI: 10.5303/pkas.2017.32.1.151

  34. DEVELOPMENT OF NEW STITCHING INTERFEROMETRY FOR THE SPICA TELESCOPE Reviewed

    Asa Yamanaka, Hidehiro Kaneda, Mitsuyoshi Yamagishi, Toru Kondo, Takuma kokusho, Kotomi Tanaka, Misaki Hanaoka, Takao Nakagawa, Mitsunobu Kawada, Naoki Isobe, Toshiaki Arai, Takashi Onaka

    Publications of The Korean Astronomical Society   Vol. 32 ( 1 ) page: 363 - 365   2017.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Korean Astronomical Society  

    DOI: 10.5303/pkas.2017.32.1.363

  35. Properties of Dust in Various Environments of Nearby Galaxies Reviewed

    Kaneda, Hidehiro; Kokusho, Takuma; Yamada, Rika; Ishihara, Daisuke; Oyabu, Shinki; Kondo, Toru; Yamagishi, Mitsuyoshi; Yasuda, Akiko; Onaka, Takashi; Suzuki, Toyoaki

    Publications of The Korean Astronomical Society   Vol. 32 ( 1 )   2017.3

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    DOI: 10.5303/PKAS.2017.32.1.135

  36. Mid- and far-infrared properties of Spitzer Galactic bubbles revealed by the AKARI all-sky surveys Reviewed

    Hattori, Yasuki; Kaneda, Hidehiro; Ishihara, Daisuke; Fukui, Yasuo; Torii, Kazufumi; Hanaoka, Misaki; Kokusho, Takuma; Kondo, Akino; Shichi, Kazuyuki; Ukai, Sota; Yamagishi, Mitsuyoshi; Yamaguchi, Yuta

    Publications of the Astronomical Society of Japan   Vol. 68 ( 3 )   2016.6

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    DOI: 10.1093/pasj/psw028

  37. A study of iron and dust in the supernova remnant IC 443 Reviewed

    Kokusho, T., Nagayama, T., Kaneda, H., Ishihara, D., Lee, Ho-Gyu., Onaka, T.

    Planetary and Space Science   Vol. 116   page: 92-96   2015.10

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.pss.2015.04.009

  38. Evaluation of InGaAs 640×512 detector array manufactured by Chunghwa Leading Photonics Tech

    Nagayama, Takahiro; Takeuchi, Nami; Kokusho, Takuma; Yamanaka, Asa; Nishiyama, Miho; Kaneda, Hidehiro

    Proceedings of the SPIE   Vol. 9154   2014.7

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    DOI: 10.1117/12.2055084

  39. Iron and dust in the supernova remnant IC443

    Kokusho, T.; Nagayama, T.; Kaneda, H.; Ishihara, D.; Lee, H. G.; Onaka, T.

    Proceedings of The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments (LCDU2013)     2013.11

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  40. Manufacturing and optical testing of 800 mm lightweight all C/SiC optics Invited Reviewed

    Kaneda, Hidehiro; Naitoh, Masataka; Nakagawa, Takao; Imai, Tadashi; Katayama, Haruyoshi; Suganuma, Masahiro; Tange, Yoshio; Sato, Ryota; Enya, Keigo; Kotani, Masaki; Maruyama, Kenta; Onaka, Takashi; Kokusho, Takuma

    Proceedings of the SPIE   Vol. 8837   2013.9

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  41. Large-area [Fe II] Line Mapping of the Supernova Remnant IC 443 with the IRSF/SIRIUS Reviewed

    Kokusho, T., Nagayama, T., Kaneda, H., Ishihara, D., Lee, Ho-Gyu., Onaka, T.

    The Astrophysical Journal Letters   Vol. 768 ( 1 ) page: 8-13   2013.5

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  42. Synergy between IRSF and AKARI Reviewed

    Nagayama, T.; Kokusho, T.; Kaneda, H.

    Publications of The Korean Astronomical Society   Vol. 27 ( 4 )   2012.11

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    DOI: 10.5303/PKAS.2012.27.4.381

  43. Experimental and numerical study of stitching interferometry for the optical testing of the SPICA Telescope

    Kaneda, Hidehiro; Naitoh, Masataka; Imai, Tadashi; Katayama, Haruyoshi; Onaka, Takashi; Nakagawa, Takao; Kawada, Mitsunobu; Yamagishi, Mitsuyoshi; Kokusho, Takuma

    Proceedings of the SPIE   Vol. 8442   2012.9

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1117/12.926879

  44. Design and status of an optical and near-infrared spectrometer for the IRSF 1.4m Telescope

    Nagayama, Takahiro; Kurita, Mikio; Kino, Masaru; Mori, Daisuke; Kokusho, Takuma

    Proceedings of the SPIE   Vol. 8446   2012.9

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    DOI: 10.1117/12.926029

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Presentations 35

  1. 近赤外輝線マッピングで探る超新星残骸と星間物質の相互作用 Invited

    國生拓摩

    SNR Workshop 2024  2024.3.1 

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    Event date: 2024.2 - 2024.3

  2. 地球型惑星の形成プロセスの理解に向けた南アフリカ望遠鏡IRSF-SAND光ファイバーリンクの開発

    國生拓摩

    第12回宇宙における生命ワークショップ  2024.2.17 

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    Event date: 2024.2

  3. 近赤外広域輝線マッピングで探る超新星爆発によるリン生成

    國生拓摩, 桂田悠紀, 金田英宏, 中岡竜也, 川端弘治

    日本天文学会2023年秋季年会  2023.9.20 

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    Event date: 2023.9

  4. 赤外線全天/広域サーベイで探る大質量星形成と星間・惑星間物質 Invited

    國生拓摩

    プラネタリウムで俯瞰する多波長全天/広域サーベイ  2023.7.19 

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    Event date: 2023.7

  5. Current status of the near-infrared spectrometer for the IRSF telescope International conference

    Takuma Kokusho

    The Workshop on Infrared Astronomy with the Infrared Survey Facility  2022.12.2 

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    Event date: 2022.12

    Language:English   Presentation type:Oral presentation (general)  

  6. Current status of the near-infrared spectrometer for the IRSF telescope

    Takuma Kokusho

    The Workshop on Infrared Astronomy with the Infrared Survey Facility  2022.12.2 

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    Event date: 2022.12

    Language:English   Presentation type:Oral presentation (general)  

  7. YSOの系統的観測で探る大マゼラン雲の星形成活動

    國生拓摩, 鳥居洋希, 金田英宏, 福井康雄, 立原研悟

    日本天文学会2022年秋季年会  2022.9.14 

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    Event date: 2022.9

  8. 狭帯域フィルターを用いた超新星残骸のリン輝線マッピング観測 Invited

    國生拓摩

    かなたミニワークショップ  2022.7.21 

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    Event date: 2022.7

  9. IRSF分光器の開発

    國生拓摩

    2020年度IRSF勉強会  2021.3.9 

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    Event date: 2021.3

    Language:Japanese   Presentation type:Oral presentation (general)  

  10. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    2020年度せいめいユーザーズミーティング  2020.8.17 

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    Event date: 2020.8

    Language:Japanese   Presentation type:Oral presentation (general)  

  11. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    2019年度光赤外天文学大学間連携WS  2019.12.3 

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    Event date: 2019.12

    Language:Japanese   Presentation type:Oral presentation (general)  

  12. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    日本天文学会2019年秋季年会  2019.9.11 

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    Event date: 2019.9

    Language:Japanese   Presentation type:Poster presentation  

  13. 超新星残骸の近赤外[PII]輝線マッピング

    國生拓摩

    第1回リンと生命の起源研究会  2019.9.2 

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    Event date: 2019.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  14. 近赤外[FeII]・H2輝線マッピングで探る超新星残骸IC443における宇宙線加速

    國生拓摩

    日本天文学会2019年春季年会  2019.3.15 

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    Event date: 2019.3

    Language:Japanese   Presentation type:Oral presentation (general)  

  15. IRSF分光器の開発

    國生拓摩

    2018年度IRSF勉強会  2019.3.7 

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    Event date: 2019.3

    Language:Japanese   Presentation type:Oral presentation (general)  

  16. CGH干渉計による自由曲面鏡の極低温での評価

    國生拓摩

    SMI技術進捗確認会  2018.9.6 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  17. 赤外光学材料KRS-5の低温での光学物性値測定

    國生拓摩

    SMI技術進捗確認会  2018.9.6 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  18. A systematic study of dust and star formation in early-type galaxies with AKARI International conference

    Takuma Kokusho, Hidehiro Kaneda, Martin Bureau, Toyoaki Suzuki, Mitsuyoshi Yamagishi, Takashi Onaka

    Cosmic Dust: origin, applications & implications  2018.6.11 

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    Event date: 2018.6

    Language:English   Presentation type:Poster presentation  

  19. SPICAのための赤外線アレイ検出器のピクセルベースでの波長感度評価法の確立

    土川拓朗, 金田英宏, 石原大助, 國生拓摩, 山口勇太, 石鉢卓也

    日本天文学会年会講演予稿集  2018.8.20 

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  20. SPICA搭載中間赤外線観測装置SMI:概念検討結果

    和田武彦, 金田英宏, 石原大助, 大薮進喜, 鈴木仁研, 深川美里, 國生拓摩, 川田光伸, 磯部直樹, 大坪貴文, 中川貴雄, 松原英雄, 權靜美, 長勢晃一, 山岸光義, 左近樹, 津村耕司, 芝井広

    日本天文学会年会講演予稿集  2018.8.20 

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  21. 「あかり」による銀河系円盤全域における赤外線バブルの統計的研究

    花岡美咲, 金田英宏, 鈴木仁研, 國生拓摩, 大薮進喜, 石原大助

    日本天文学会年会講演予稿集  2018.2.20 

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  22. 「あかり」赤外線全天データで探る早期型銀河ダストの無バイアスな描像

    金田英宏, 國生拓摩, 鈴木仁研, 村田勝寛, 近藤晶乃, 山岸光義

    日本天文学会年会講演予稿集  2017.2.28 

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  23. 「あかり」赤外線全天マップで探る早期型銀河のダストと分子ガス・X線プラズマの関係

    國生拓摩, 金田英宏, 鈴木仁研, 近藤晶乃, 村田勝寛, 山岸光義

    日本天文学会年会講演予稿集  2018.2.20 

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    Language:Japanese  

  24. 「あかり」赤外線全天観測による早期型銀河の星形成の系統的研究

    國生拓摩, 金田英宏, 鈴木仁研, 村田勝寛, 近藤晶乃, 山岸光義

    日本天文学会年会講演予稿集  2017.2.28 

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  25. 「あかり」赤外線分光観測で探る星形成銀河における炭化水素ダストの変成

    近藤晶乃, 金田英宏, 鈴木仁研, 村田勝寛, 國生拓摩, 石原大助, 大薮進喜, 山岸光義

    日本天文学会年会講演予稿集  2017.2.28 

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  26. 新しいIRSF点源カタログを用いた LMC減光マップの作成

    國生拓摩

    2017年度IRSF勉強会  2017.3.5 

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  27. 超新星残骸の近赤外 [PII] 輝線マッピング観測

    國生拓摩

    第 1 回リンと生命の起源研究会  2019.9.2 

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    Language:Japanese   Presentation type:Oral presentation (general)  

  28. A systematic study of dust and star formation in early-type galaxies with AKARI

    Takuma Kokusho, Hidehiro Kaneda, Martin Bureau, Toyoaki Suzuki, Mitsuyoshi Yamagishi, Takashi Onaka

    Cosmic Dust: origin, applications & implications  2018.6.11 

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    Language:English   Presentation type:Poster presentation  

  29. 近赤外リン輝線マッピングで探る超新星爆発によるリン生成

    國生拓摩

    第2回リンと生命の起源研究会  2023.9.11 

  30. 近赤外[FeII]・H2輝線マッピングで探る超新星残骸IC443 における宇宙線加速

    國生拓摩, 鳥居洋希, 金田英宏, 石原大助, 永山貴宏, 尾中敬

    日本天文学会2019年春季年会  2019.3.15 

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  31. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    光赤外天文学大学間連携 WS  2019.12.2 

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  32. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    2020年度IRSF勉強会  2021.3.9 

  33. IRSF望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩

    2020年度せいめいユーザーズミーティング  2020.8.17 

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  34. IRSF分光器の開発

    國生拓摩

    2018年度IRSF勉強会  2019.3.7 

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  35. IRSF 望遠鏡に搭載する近赤外線分光器の開発

    國生拓摩, 古田拓也, 石鉢卓也, 森鼻久美子, 金田英宏, 永山貴宏, 石原大助

    日本天文学会2019年秋季年会  2019.9.11 

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    Language:Japanese   Presentation type:Poster presentation  

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Research Project for Joint Research, Competitive Funding, etc. 6

  1. 極低温下における自由曲面鏡の形状評価のための高精度・高汎用干渉計の開発

    2023.7 - 2024.2

    搭載機器基礎開発実験費 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2420000 ( Direct Cost: \2200000 、 Indirect Cost:\220000 )

  2. 地球型惑星の形成プロセスの理解に向けた南アフリカ望遠鏡IRSF-SAND光ファイバーリンクの開発

    2023.4 - 2024.3

    アストロバイオロジーセンタープロジェクト研究 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1465000

  3. 極低温下における⾃由曲⾯鏡の形状評価のための⾼精度・⾼汎⽤⼲渉計の開発

    2022.7 - 2023.2

    搭載機器基礎開発研究費 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2860000 ( Direct Cost: \2600000 、 Indirect Cost:\260000 )

  4. 極低温下における⾃由曲⾯鏡の形状評価のための⾼精度・⾼汎⽤⼲渉計の開発

    2021.7 - 2022.2

    搭載機器基礎開発研究費 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1100000 ( Direct Cost: \1000000 、 Indirect Cost:\100000 )

  5. 生命誕生の理解へ向けた超新星爆発によるリン生成メカニズムの観測的研究

    2021.4 - 2022.3

    稲盛研究助成 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1000000 ( Direct Cost: \1000000 )

  6. 自由曲面鏡の低温での形状評価方法の開発

    2019.6 - 2020.2

    搭載機器基礎開発研究費 

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    Grant type:Competitive

    Grant amount:\2900000 ( Direct Cost: \2636000 、 Indirect Cost:\264000 )

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KAKENHI (Grants-in-Aid for Scientific Research) 8

  1. 極低温下における自由曲面鏡の形状評価のための高精度・高汎用干渉計の開発

    2023.7 - 2024.2

    宇宙航空研究開発機構 宇宙科学研究所  搭載機器基礎開発実験費 

  2. 地球型惑星の形成プロセスの理解に向けた南アフリカ望遠鏡IRSF-SAND光ファイバーリンクの開発

    2023.4 - 2024.3

    自然科学研究機構アストロバイオロジーセンター  令和5年度アストロバイオロジーセンタープロジェクト研究 

  3. 極低温下における自由曲面鏡の形状評価のための高精度・高汎用干渉計の開発

    2022.7 - 2023.2

    宇宙航空研究開発機構 宇宙科学研究所  搭載機器基礎開発実験費 

  4. 生命誕生の理解に向けた超新星爆発によるリン生成の精密定量

    Grant number:22H01264  2022.4 - 2026.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    國生 拓摩, 永山 貴宏

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    Authorship:Principal investigator 

    Grant amount:\17680000 ( Direct Cost: \13600000 、 Indirect Cost:\4080000 )

    リンはDNAや細胞壁などの材料で、生命を司る元素のひとつである。その起源は超新星爆発にまでさかのぼるが、リンの生成メカニズムや、惑星・生命へ至るプロセスは理解されていない。本研究は近赤外リン輝線に着目し、狭帯域フィルターを用いた超新星残骸のリン輝線マッピング観測を行う。検出されるリンには星間物質を起源とする成分が含まれる可能性があるため、専用分光器を用いて爆発のため高速で運動する超新星起源のリンを同定する。本手法により多くの天体を観測して超新星起源のリンを徹底して見つけ出し、超新星爆発によるリン生成について網羅的な知見を得ることで、リン観測を軸とした宇宙生物学の新しい分野を開拓する。

  5. 極低温下における自由曲面鏡の形状評価のための高精度・高汎用干渉計の開発

    2021.7 - 2022.2

    宇宙航空研究開発機構 宇宙科学研究所  搭載機器基礎開発実験費 

  6. 大マゼラン雲の近赤外輝線サーベイで探るスーパーシェルによる誘発的星形成

    Grant number:19K14757  2019.4 - 2024.3

    日本学術振興会  科学研究費助成事業  若手研究

    國生 拓摩

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    大マゼラン雲には直径1 kpcにも及ぶスーパーシェルが点在し、星間物質を圧縮して星形成を誘発すると考えられているが、大きな構造のため詳細な観測が難しく、そのメカニズムは謎に包まれている。本研究では、大マゼラン雲に対し衝撃波トレーサーの近赤外[FeII]・H2輝線サーベイ観測を行い、星間物質と相互作用するシェルを徹底して見つけ出す。また近・中間赤外線データをもとに前主系列星の位置と進化段階を調べ、星形成を伴うシェルを同定する。さらに、これらの星形成シェルの分光フォローアップ観測により星間物質の物理状態を調べ、スーパーシェルによる誘発的星形成のメカニズムを明らかにする。
    星団の放射圧や超新星爆発の衝撃波の複合体であるスーパーシェルは、星間物質との相互作用により星形成を誘発すると考えられている。しかしスーパーシェルは大規模な構造であるため、周りの星形成との関係を調べることが難しく、その物理メカニズムは良く理解されていない。本研究では衝撃波トレーサ―である近赤外[FeII]・H2輝線の広域マッピングや、前主系列星の進化段階をもとに星形成誘発のメカニズムを探る。
    赤外線アーカイブデータを用いて大マゼラン雲の前主系列星の研究を進めた。具体的には、約5000天体の赤外線SEDを解析し、その空間分布や星質量、進化段階を調べた。その結果、スーパーシェルを含む水素ガスに沿って若い前主系列星が分布しており、スーパーシェルによる星形成トリガーの様子を捉えた。その上で、スーパーシェルに付随する前主系列星は星質量が系統的に小さいことが分かった。このことから、スーパーシェルによる星形成トリガーは大質量星の形成には有効でないことが示唆される。
    IRSF望遠鏡に狭帯域フィルターを搭載して、スーパーシェルの[FeII]・H2輝線マッピングを行う予定であったが、新型コロナウイルスの影響のため、昨年度に引き続き観測を実施できていない。一方で、分光フォローアップのための専用分光器の準備を進めた。本装置は完成しているものの、検出器の読み出し回路に一部不具合があった。この影響で安定した運用が難しかったため、新しい読み出し回路を設計、製作して、観測装置に取り付けて問題なく動作することを確かめた。
    本研究では、大マゼラン雲の輝線マッピング観測と、既存のアーカイブデータを用いた前主系列星の解析結果をもとに、スーパーシェルによる星形成誘発のプロセスを調べる。当初はこれらの観測とデータ解析を並行して進める予定であったが、新型コロナウイルス拡大の影響のため、観測で用いるIRSF望遠鏡が2022年度前半までおよそ2年間シャットダウンしており、観測を十分に実施できていない。アーカイブデータを用いた前主系列星の解析はおおむね順調に進み、輝線マッピング観測で優先して観測する天体も選定済みである。
    2022年度の後半にIRSF望遠鏡は復帰して、現在はシャットダウン前と同じ観測性能が確かめられている。このため、2022年度の後半から南アフリカ共和国に渡航して、上記の輝線マッピング観測を開始した。しかし、当初予定していた大マゼラン雲のスーパーシェル領域をほとんどカバーできていないため、研究進捗は遅れていると判断した。
    既存のデータアーカイブを用いた大マゼラン雲の前主系列星の解析から、とくに若い天体を多く伴うスーパーシェルを特定した。さらにスーパーシェル以外の領域でも、水素ガスの濃いシェルに沿って若い天体が分布する領域を特定した。これらの領域は誘発的星形成が起きている可能性が高いため、優先して[FeII]・H2輝線のマッピング観測を行う。IRSF望遠鏡は、2022年度の後半に新型コロナウイルス拡大に伴うシャットダウンから復帰したため、観測は問題なく実施できる予定である。これらの観測結果を組み合わせて、銀河全体の星形成活動における誘発プロセスの重要性を探る。また、上記の観測と並行してIRSF近赤外線分光器の開発を進め、望遠鏡へ搭載する。同装置の試験観測を行い、期待される性能を確かめ、スーパーシェルの分光フォローアップを行う。とくに前主系列星が多く、[FeII]・H2輝線で明るい衝撃波シェルを対象に近赤外線スペクトルを解析し、星間ガスの物理状態を調べて星形成誘発の条件を探る。

  7. A study of the supernova nucleosynthesis of phosphorus with near-infrared spectral mapping of supernova remnants

    Grant number:17H06739  2017.8 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Research Activity Start-up

    Kokusho Takuma

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2600000 ( Direct Cost: \2000000 、 Indirect Cost:\600000 )

    In order to understand the nucleosynthesis mechanism of phosphorus by supernova, we developed a near-infrared spectrometer to perform mapping observations of supernova remnants in the [PII] emission. The spectrometer is equipped with a near-infrared slit viewer, which enables us to perform very precise spectral mapping. We attached the spectrometer to the 1-m telescope operated by Kagoshima University and successfully observed near-infrared spectra of the standard stars, from which we have evaluated the optical performance of the spectrometer. We have also carried out spectral mapping observations of some supernova remnants, such as W49B.

  8. 赤外線大規模観測で解き明かす、超新星残骸における星間物質の進化

    Grant number:14J03161  2014.4 - 2017.3

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    國生 拓摩

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    昨年度に引き続き、南アフリカ望遠鏡IRSFに搭載する近赤外線分光器の開発を行った。本年度は主に分光部の光学調整を進めた。具体的には、望遠鏡焦点位置にピンホールを設置して常温下で測定を行い、光学素子の配置を調整した。次に光学系を冷凍機で70 Kまで冷却し、低温下での結像性能を評価した。その結果、像のサイズはシミュレーションから期待されるより広がっており、熱収縮による光学素子の移動量が想定と異なることや、光学素子の形状誤差の影響が考えられる。本観測装置について、予想外の検出器関連のトラブルがあり、本研究課題の採用期間中に望遠鏡に取り付けて観測まで行うことはできなかったが、必要な光学コンポーネントや検出器の読み出しシステムを完成させた。今後も引き続き開発を進めていく予定である。
    上記の分光器の開発に加え、早期型銀河の星形成の研究を行った。早期型銀河は銀河進化の末期にあり、X線プラズマがガスの収縮を妨げて星形成を抑制すると考えられているが、その観測的証拠は十分ではない。この早期型銀河の星形成活動について統一的な描像を得るため、観測やシミュレーションにより種々の系統的研究が行われている260個の早期型銀河(Cappellari et al. 2011)に対し、赤外線天文衛星「あかり」の観測結果を用いてサンプル銀河の赤外線放射特性を調べた。具体的には、「あかり」衛星の全天観測にWISE衛星などの観測を加え、有機物PAHの光度を求めた。得られたPAH光度を銀河の星形成率に換算し、この結果を分子ガスの質量と比較しところ、星間物質を星に変換する効率は通常の星形成銀河と同程度であった。この結果は、星形成の材料である星間物質の減少が原因で星形成が不活発となっていることを意味しており、早期型銀河の星形成活動について重要な観測的示唆を与えるものである。

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Teaching Experience (On-campus) 5

  1. Laboratory in Physics

    2023

  2. Laboratory in Physics

    2023

  3. Physics Seminars IX-II

    2022

  4. 物理学実験

    2022

  5. 物理学実験

    2021