2021 Fiscal Year Final Research Report
Study on binary evolutions with physical process around neutron star: Application to neutron star ULX
| Project/Area Number |
18K03706
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 16010:Astronomy-related
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| Research Institution | Kyushu Sangyo University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Keywords | 連星進化 / 中性子星 / X線連星 / 超高輝度X線天体 |
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| Outline of Final Research Achievements |
In this research project, we have developed a new binary evolution simulation method that takes into account physical processes around neutron stars, such as magnetic fields, accretion disk formation and mass loss, in order to study the evolutionary processes of binary systems including neutron stars. In particular, we have aimed to understand the evolutionary processes of neutron star-powered Ultra-Luminous X-ray sources (NS ULXs).
Through this research, we have elucidated the characteristics and evolutionary processes of potential NS ULX binary systems, as well as the disk formation process, magnetic field and spin co-evolution of neutron stars in X-ray binary systems. We show that many Be-type high-mass X-ray binaries, which constitute the majority of X-ray binaries, can become ULXs during their evolution, and we clarify the universality of NS ULXs.
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| Free Research Field |
天文学
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| Academic Significance and Societal Importance of the Research Achievements |
超高輝度X線天体（ULX）は発見以来，通常降着する中間質量ブラックホール（BH）か，超臨界降着する星質量BHかが問題となっていた．もしこれらの天体が中間質量BHを含むのであれば，銀河中心に位置する超巨大BHの形成シナリオに重大なインパクトを与え，ひいては銀河の進化過程や我々の体を形作る物質の起源を明らかにするうえでも重要である．
それに対し，本研究ではULXの中で中性子星を放射源とするものが少なくないことを示した．ULXに占めるBHの割合がわかれば，未解明な点の多い大質量形成・進化や超新星爆発のメカニズムに至るまで，多くの示唆が得られる．本研究はその先鞭をつけるものである．
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