写真a

SUSA Hajime

Position

Professor

Research Field

Particle/Nuclear/Cosmic ray/Astro physics

Graduating School 【 display / non-display

  •  
    -
    1992.03

    Kyoto University   Faculty of Science   Graduated

Graduate School 【 display / non-display

  •  
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    1997.03

    Kyoto University  Graduate School, Division of Natural Science  Doctor's Course  Completed

Campus Career 【 display / non-display

  • 2007.04
    -
    2011.03

    KONAN UNIVERSITYFaculty of Science and Engineering   Associate Professor  

 

Published Papers 【 display / non-display

  • Driving conditions of protostellar outflows in different star-forming environments

    Koki Higuchi, Masahiro N Machida, Hajime Susa

    Monthly Notices of the Royal Astronomical Society   486 ( 3 ) 3741 - 3754   2019.07  [Refereed]

    Joint Work

    DOI

  • Merge or Survive: Number of Population III Stars per Minihalo

    Hajime Susa

    The Astrophysical Journal   877 ( 2 ) 99   2019.06  [Refereed]

    Single Work

    DOI

  • Blocking metal accretion onto low-mass population III stars by stellar wind

    Tanaka S.J, Chiaki G, Tominaga N, Susa H.

    AIP Conference Proceedings   1947   2018.04

    Joint Work

    Low-mass population III (PopIII) stars could survive up until the present. They would be found in the halo of Our Galaxy, if they exist. Non-detection of low-mass PopIII stars in our Galaxy suggests that PopIII stars have a top-heavy IMF. On the other hand, some claims that the lack of such stars is as a result of metal enrichment of their surface by accretion of heavy elements from interstellar medium (ISM). We investigate effects of the stellar wind on the metal accretion onto low-mass PopIII stars because accretion of the local ISM onto the Sun is prevented by the solar wind even for neutrals. We find that low-mass PopIII stars traveling across the Galaxy forms the stellar magnetosphere in most of their life. Once the magnetosphere is formed, most of neutral interstellar particles are photoionized before reaching to the stellar surface and are blown away by the wind. This demonstrates that low-mass PopIII stars remain pristine and will be found as metal free stars and that further searches for them are valuable to constrain the IMF of PopIII stars....

    DOI

  • Metal-poor star formation triggered by the feedback effects from Pop III stars

    Gen Chiaki, Hajime Susa, Shingo Hirano

    Monthly Notices of the Royal Astronomical Society   475 ( 4 ) 4378 - 4395   2018.02  [Refereed]

    Joint Work

    DOI

  • Evolution of magnetic fields in collapsing star-forming clouds under different environments

    Koki Higuchi, Masahiro N Machida, Hajime Susa

    Monthly Notices of the Royal Astronomical Society   475 ( 3 ) 3331 - 3347   2018.01  [Refereed]

    Joint Work

    DOI

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Books etc 【 display / non-display

  • The Encyclopedia of Cosmology Volume 2: Numerical Simulations in Cosmology

    K.Nagamine, A.Klypin,K.Dolag,H.Susa,V.Bromm,I,Shlosman,G.L.Bryan,D.Nagai (Part: Joint Work ,  chapter 4 )

    World Scientific  2018.05 ISBN: 978-981-4656-19-1

  • The Encyclopedia of Cosmology

    Susa, Hajime (Part: Other ,  Chapter 4 )

    World Scientific  2018.05 ISBN: 9789814656238

  • General Physics(jointly worked)

    Humitaka Sato, Hajime Susa (Part: Joint Work )

    Shokabo  2010.08 ISBN: 978-4-7853-2827-6

  • Tours symposium on nuclear physics and astrophysics-VII : Kobe, Japan 16-20 November 2009

    Tours Symposium on Nuclear Physics, 須佐 元, 宇都宮 弘章, Arnould Marcel, Galès Sydney, 本林 透, Scheidenberger Christoph (Part: Other )

    American Institute of Physics  2010 ISBN: 9780735407848

  • 一般物理学 : 一歩先に進みたい人へ

    佐藤 文隆, 須佐 元 (Part: Other )

    裳華房  2010 ISBN: 9784785328276

Review Papers (Misc) 【 display / non-display

  • Ionization degree and magnetic diffusivity in the primordial star-forming clouds

    arXiv e-prints     2019.04

    Single Work

    Magnetic fields play such roles in star formation as the angular momentum transport in star-forming clouds, thereby controlling circumstellar disc formation and even binary star formation efficiency. The coupling between the magnetic field and gas is determined by the ionization degree in the gas. Here, we calculate the thermal and chemical evolution of the primordial gas by solving chemical reaction network where all the reactions are reversed. We find that at ~ 10^14-10^18 /cm^3, the ionization degree becomes 100-1000 times higher than the previous results due to the lithium ionization by thermal photons trapped in the cloud, which has been omitted so far. We construct the minimal chemical network which can reproduce correctly the ionization degree as well as the thermal evolution by extracting 36 reactions among 13 species. Using the obtained ionization degree, we evaluate the magnetic field diffusivity. We find that the field dissipation can be neglected for global fields coherent over > a tenth of the cloud size as long as the field is not so strong as to prohibit the collapse. With magnetic fields strong enough for ambipolar diffusion heating to be significant, the magnetic pressure effects to slow down the collapse and to reduce the compressional heating become more important, and the temperature actually becomes lower than in the no-field case....

  • TOURS SYMPOSIUM ON NUCLEAR PHYSICS AND ASTROPHYSICS-VII

    American Institute of Physics Conference Series     2010.06

    Single Work

    ...

  • 星ふる里の麓にて - 銀河形成理論次の10年 -

    須佐 元

    天文月報 ( 日本天文学会 )  97 ( 7 ) 425   2004.11

    Introduction and explanation (international conference proceedings)   Single Work

  • 宇宙物理における輻射輸送問題

    須佐 元

    天文月報 ( 日本天文学会 )  96 ( 12 ) 642   2003.12

    Introduction and explanation (international conference proceedings)   Single Work

  • 銀河形成における背景紫外輻射場の役割

    須佐 元

    天文月報 ( 日本天文学会 )  96 ( 2 ) 77   2003.02

    Introduction and explanation (international conference proceedings)   Single Work

Conference Activities & Talks 【 display / non-display

  • Stellar wind prevents the ISM gas from accreting onto the popIII stars

    Susa, H.; Tanaka, S.; Chiaki, G.; Tominaga, N.

    Francesco’s Legacy –Star Formation in Space and Time  (イタリア・フィレンツェ)  2017.06  -  2017.06 

  • The effects of magnetic dissipation on the star formation in low metallicity environments

    Hajime Susa, Doi Kentaro, Kazuyuki Omukai

    First Stars, Galaxies, and Black Holes: Now and Then  (Groningen)  2015.06  -  2015.06 

  • The IMF of the First Stars

    Hajime Susa, Kenji Hasegawa, Nozomu Tominaga

    The physics of first star and galaxy formation  (Edinburgh)  2014.06  -  2014.06 

  • On the IMF of first stars

    Susa, H.; Hasegawa, K.; Tominaga, N.

    ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 2013  (Tsukuba)  2013.11  -  2013.11 

  • On the Mass of First Stars

    Hajime Susa

    Workshop on Cosmological Radiation Transfer ComparisonIV  (Austin)  2012.12  -  2012.12 

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Grant-in-Aid for Scientific Research 【 display / non-display

  • Grant-in-Aid for Scientific Research(A)

    Project Year: 2017.04  -   

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2017.04  -   

  • Grant-in-Aid for Scientific Research(C)

    Project Year: 2013.04  -  2016.03 

  • Grant-in-Aid for Scientific Research(C)

    Project Year: 2010.04  -   

  • Grant-in-Aid for Young Scientists(B)

    Project Year: 2005.04  -  2007.03 

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