Tanaka, Kunihiko



Faculty of Science and Technology, Department of Physics (Yagami)


Research Associate/Assistant Professor/Instructor

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Career 【 Display / hide

  • 2005.04

    University of Tokyo, Institute of Astronomy

  • 2008.04

    National Astronomical Observatory Japan, Nobeyama Radio Observatory, PD


Research Areas 【 Display / hide

  • Astronomy

Research Keywords 【 Display / hide

  • Radio Astronomy

Research Themes 【 Display / hide

  • 銀河系中心、大質量星形成、近傍銀河, 


     View Summary

    Galactic Center, Massive Star Formation, Nearby Galaxies


Papers 【 Display / hide

  • Clustered Star Formation in the Center of NGC 253 Contributes to Driving the Ionized Nuclear Wind

    Mills E.A.C., Gorski M., Emig K.L., Bolatto A.D., Levy R.C., Leroy A.K., Ginsburg A., Henshaw J.D., Zschaechner L.K., Veilleux S., Tanaka K., Meier D.S., Walter F., Krieger N., Ott J.

    Astrophysical Journal (Astrophysical Journal)  919 ( 2 )  2021.10

    ISSN  0004637X

     View Summary

    We present new 3 mm observations of the ionized gas toward the nuclear starburst in the nearby (D ∼ 3.5 Mpc) galaxy NGC 253. With ALMA, we detect emission from the H40α and He40α lines in the central 200 pc of this galaxy on spatial scales of ∼4 pc. The recombination line emission primarily originates from a population of approximately a dozen embedded super star clusters in the early stages of formation. We find that emission from these clusters is characterized by electron temperatures ranging from 7000 to 10,000 K and measures an average singly ionized helium abundance Y + = 0.25 0.06, both of which are consistent with values measured for H ii regions in the center of the Milky Way. We also report the discovery of unusually broad line width recombination line emission originating from seven of the embedded clusters. We suggest that these clusters contribute to the launching of the large-scale hot wind observed to emanate from the central starburst. Finally, we use the measured recombination line fluxes to improve the characterization of overall embedded cluster properties, including the distribution of cluster masses and the fractional contribution of the clustered star formation to the total starburst, which we estimate is at least 50%.

  • Atomic Carbon in the Central Molecular Zone of the Milky Way : Possible Cosmic–ray Induced Chemistry or Time–dependent Chemistry Associated with SNR Sagittarius A East

    Kunihiko Tanaka, Makoto Nagai, Kazuhisa Kamegai

    Astrophysical Journal (IOP publishing )  915 ( 2 ) 79 2021.07

    Research paper (scientific journal), Joint Work, Accepted

  • The Distribution and Origin of C$_2$H in NGC 253 from ALCHEMI

    J. Holdship, S. Viti, S. Martín, N. Harada, J. Mangum, K. Sakamoto, S. Muller, K. Tanaka, Y. Yoshimura, K. Nakanishi, R. Herrero-Illana, S. Mühle, R. Aladro, L. Colzi, K. L. Emig, S. García-Burillo, C. Henkel, P. Humire, D. S. Meier, V. M. Rivilla, P. van der Werf

    A&A 654, A55 (2021)  2021.07

     View Summary

    Observations of chemical species can provide an insight into the physical
    conditions of the emitting gas but it is important to understand how their
    abundances and excitation vary within different heating environments. C$_2$H is
    a molecule typically found in PDR regions of our own Galaxy but there is
    evidence to suggest it also traces other regions undergoing energetic
    processing in extragalactic environments. As part of the ALCHEMI ALMA large
    program, the emission of C$_2$H in the central molecular zone of the nearby
    starburst galaxy NGC 253 was mapped at 1.6 " (28 pc) resolution and
    characterized to understand its chemical origins. Spectral modelling of the
    N=1-0 through N=4-3 rotational transitions of C$_2$H was used to derive the
    C$_2$H column densities towards the dense clouds in NGC 253. Chemical
    modelling, including PDR, dense cloud, and shock models were then used to
    investigate the chemical processes and physical conditions that are producing
    the molecular emission. We find high C$_2$H column densities of $\sim 10^{15}
    cm^{-3}$ detected towards the dense regions of NGC 253. We further find that
    these column densities cannot be reproduced by assuming that the emission
    arises from the PDR regions at the edge of the clouds. Instead, we find that
    the C$_2$H abundance remains high even in the high visual extinction interior
    of these clouds and that this is most likely caused by a high cosmic-ray
    ionization rate.

  • ALCHEMI: an ALMA Comprehensive High-resolution Extragalactic Molecular Inventory. Survey presentation and first results from the ACA array

    S. Martín, J. G. Mangum, N. Harada, F. Costagliola, K. Sakamoto, S. Muller, R. Aladro, K. Tanaka, Y. Yoshimura, K. Nakanishi, R. Herrero-Illana, S. Mühle, S. Aalto, E. Behrens, L. Colzi, K. L. Emig, G. A. Fuller, S. García-Burillo, T. R. Greve, C. Henkel, J. Holdship, P. Humire, L. Hunt, T. Izumi, K. Kohno, S. König, D. S. Meier, T. Nakajima, Y. Nishimura, M. Padovani, V. M. Rivilla, S. Takano, P. P. van der Werf, S. Viti, Y. T. Yan

    arXiv  2021

    Joint Work, Accepted

  • Starburst Energy Feedback Seen Through HCO$^+$/HOC$^+$ Emission in NGC 253 from ALCHEMI

    Nanase Harada, Sergio Martín, Jeffrey G. Mangum, Kazushi Sakamoto, Sebastien Muller, Kunihiko Tanaka, Kouichiro Nakanishi, Rubén Herrero-Illana, Yuki Yoshimura, Stefanie Mühle, Rebeca Aladro, Laura Colzi, Víctor M. Rivilla, Susanne Aalto, Erica Behrens, Christian Henkel, Jonathan Holdship, P. K. Humire, David S. Meier, Yuri Nishimura, Paul P. van der Werf, Serena Viti

    Astrophysical Journal  2021

    Joint Work, Accepted

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Papers, etc., Registered in KOARA 【 Display / hide

Presentations 【 Display / hide

  • Star Formation Conditions In the Milky Way’s Galactic Central Molecular Zone

    TANAKA Kunihiko

    Star Formation in Different Environments 2017, 2017.08

  • Search for the CO-dark Mass in the Central Molecular Zone by using the ASTE 10-m Telescope

    TANAKA Kunihiko

    IAUS 322: The Multi-Messenger Astrophysics of the Galactic Centre, 2016.07, Oral Presentation(general)

  • CO-0.30-0.07: A Candidate Site of Collision-induced Massive Star Formation in the Milky Way's Central Molecular Zon

    TANAKA Kunihiko

    The 6th Zermatt ISM Symposium",, 2015.09, Oral Presentation(general)

  • Giant Molecular Clouds with High Abundance of Atomic Carbon and Cyano Radical in the Milky Way's Central Molecular Zone

    TANAKA Kunihiko

    IAU General Assembly, Meeting #29 (Honolulu, HA, USA) , 2015.08, Poster (general), International Astronomical Union

  • The ASTE Galactic Center Survey in the 350 and 500 GHz Bands

    TANAKA Kunihiko

    New Trends in Radio Astronomy in the ALMA Era / the 30th Anniversary of Nobeyama Radio Observatory (Hakone, Kanagawa, Japan) , 2012.12, Oral Presentation(general)

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • 銀河系中心領域での局所的な爆発的星形成現象


    日本学術振興会, Grant-in-Aid for Scientific Research, 田中邦彦, Research grant, Principal Investigator

  • ミリ波-サブミリ波観測で探る銀河系中心活動性


    日本学術振興会, Grant-in-Aid for Scientific Research, Research grant, Principal Investigator

Works 【 Display / hide

  • 夏の星空から始める天文学:銀河系中心の不思議な天体たち






Courses Taught 【 Display / hide











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Memberships in Academic Societies 【 Display / hide

  • Astronomical Society Japan