Tanaka, Kunihiko



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


Research Associate/Assistant Professor/Instructor

External Links

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

  • Natural Science / 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

  • First extragalactic detection of a phosphorus-bearing molecule with ALCHEMI: Phosphorus nitride (PN)

    Haasler, D. search by orcid ; Rivilla, V. M. ; Martín, S. ; Holdship, J. ; Viti, S. ; Harada, N. ; Mangum, J. ; Sakamoto, K. ; Muller, S. ; Tanaka, K. ; Yoshimura, Y. ; Nakanishi, K. ; Colzi, L. search by orcid ; Hunt, L. search by orcid ; Emig, K. L. ; Aladro, R. ; Humire, P. ; Henkel, C. ; van der Werf, P.

    Astronomy & Astrophysics 659   158 2022.03

    Research paper (scientific journal), Joint Work, Accepted

  • Energizing Star Formation: The Cosmic Ray Ionization Rate in NGC 253 Derived From ALCHEMI Measurements of H$_3$O$^+$ and SO

    Holdship, Jonathan ; Mangum, Jeffrey G. ; Viti, Serena ; Behrens, Erica ; Harada, Nanase ; Martín, Sergio ; Sakamoto, Kazushi ; Muller, Sebastien ; Tanaka, Kunihiko ; Nakanishi, Kouichiro ; Herrero-Illana, Rubén ; Yoshimura, Yuki ; Aladro, Rebeca ; Colzi, Laura ; Emig, Kimberly L. ; Henkel, Christian ; Nishimura, Yuri ; Rivilla, Víctor M. ; van der Werf, Paul P.

    The Astrophysical Journal  2022

    Research paper (scientific journal), Joint Work, Accepted

  • Methanol masers in NGC 253 with ALCHEMI

    Humire, P. K. ; Henkel, C. ; Hernández-Gómez, A. ; Martín, S. ; Mangum, J. ; Harada, N. ; Muller, S. ; Sakamoto, K. ; Tanaka, K. ; Yoshimura, Y. ; Nakanishi, K. ; Mühle, S. ; Herrero-Illana, R. ; Meier, D. S. ; Caux, E. ; Aladro, R. ; Mauersberger, R. ; Viti, S. ; Colzi, L. ; Rivilla, V. M. ;

    Astronomy and Astrophysics  2022

    Research paper (scientific journal), Accepted

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

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

    Astronomy and Astrophysics (Astronomy and Astrophysics)  656 2021.12

    Research paper (scientific journal), Accepted,  ISSN  00046361

     View Summary

    Context. The interstellar medium is the locus of physical processes affecting the evolution of galaxies which drive or are the result of star formation activity, supermassive black hole growth, and feedback. The resulting physical conditions determine the observable chemical abundances that can be explored through molecular emission observations at millimeter and submillimeter wavelengths. Aims. Our goal is to unveiling the molecular richness of the central region of the prototypical nearby starburst galaxy NGC 253 at an unprecedented combination of sensitivity, spatial resolution, and frequency coverage. Methods. We used the Atacama Large Millimeter/submillimeter Array (ALMA), covering a nearly contiguous 289 GHz frequency range between 84.2 and 373.2 GHz, to image the continuum and spectral line emission at 1.6″(∼28 pc) resolution down to a sensitivity of 30 - 50 mK. This article describes the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) large program. We focus on the analysis of the spectra extracted from the 15″ (∼255 pc) resolution ALMA Compact Array data. Results. We modeled the molecular emission assuming local thermodynamic equilibrium with 78 species being detected. Additionally, multiple hydrogen and helium recombination lines are identified. Spectral lines contribute 5 to 36% of the total emission in frequency bins of 50 GHz. We report the first extragalactic detections of C2H5OH, HOCN, HC3HO, and several rare isotopologues. Isotopic ratios of carbon, oxygen, sulfur, nitrogen, and silicon were measured with multiple species. Concluison. Infrared pumped vibrationaly excited HCN, HNC, and HC3N emission, originating in massive star formation locations, is clearly detected at low resolution, while we do not detect it for HCO+. We suggest high temperature conditions in these regions driving a seemingly "carbon-rich"chemistry which may also explain the observed high abundance of organic species close to those in Galactic hot cores. The Lvib/LIR ratio was used as a proxy to estimate a 3% contribution from the proto super star cluster to the global infrared emission. Measured isotopic ratios with high dipole moment species agree with those within the central kiloparsec of the Galaxy, while those derived from 13C/18O are a factor of five larger, confirming the existence of multiple interstellar medium components within NGC 253 with different degrees of nucleosynthesis enrichment. The ALCHEMI data set provides a unique template for studies of star-forming galaxies in the early Universe.

  • 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

    Research paper (scientific journal), Accepted,  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%.

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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, 


  • 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, 


    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",, 


    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) , 


    Poster presentation, 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) , 


    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, 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