• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

1997 Fiscal Year Final Research Report Summary

Search of dark matter by microlensing observations

Research Project

Project/Area Number 08044066
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionJoint Research
Research Field 素粒子・核・宇宙線
Research InstitutionNagoya University

Principal Investigator

MURAKI Yasushi  Solar-Terrestrial Environment Laboratory, Nagoya University Professor, 太陽地球環境研究所, 教授 (70013430)

Co-Investigator(Kenkyū-buntansha) ヨック フィリップ  オークランド大学, 理学部, 教授
NAKAMURA Takashi  Faculty of Science, Kyoto University Professor, 理学部, 教授 (80155837)
ABE Fumio  Solar-Terrestrial Environment Laboratory, Nagoya University Associate Professor, 太陽地球環境研究所, 助教授 (80184224)
MATSUBARA Yutaka  Solar-Terrestrial Environment Laboratory, Nagoya University Associate Professor, 太陽地球環境研究所, 助教授 (80202323)
SEKIGUCHI Maki  Institute for Cosmic Ray Research, University of Tokyo Associate Professor, 宇宙線研究所, 助教授 (40216528)
YOCK Philip  Faculty of science, Auckland University Professor
Project Period (FY) 1996 – 1997
Keywordscosmic dark matter / mosaic ccd camera / Large Magellanic Cloud / galactic center / brown dwarf / global network / MACHO / extra-solar planet
Research Abstract

An extremly sensitive 'gravitational microlensing' technique, that was originally proposed by Einstein, is being used at the Mt.John University Observatory by a Japan/NZ collaboration MOA to carry out various fundamental measurements. The collaboration brings together resources and expertise from several NZ and Japanese institutions. Additional US and Australian expertise and resources are involved through MOA's participation in a world-wide network of southern observatories all using the microlensing technique. The network is known as GMAN.Both MOA and GMAN utilise Mt.John's competitive edge in terms of latitude and longitude for observations of the Magellanic Clouds. What we have discoverd are as follows :
1) The composition of the halo of the Galaxy is unknown. The MOA group has found that it is comprised of<10% of low-mass brown dwarf stars, consistent with other groups. In May 1998, observations will be made with new CCD camera and improved search technique.
2) Discovery-of an extra Jupitor in July 24th 1997. It has been confirmed that the microlensing technique has the required sensitivity for the detection of extra-solar planets. Round-the-clock observations were made by the GMAN network, and by another network known as PLANET,a possible example of planet was found. Again in May 1998, a much larger CCD camera with 24 million rather 9 million pixels will be used at Mt.John, and the data analysis will be carried out on-line. Statistically significant data on the frequency of stars with planetary systems similar to ours, potentially capable of supporting life, are expected to be discovered.
3) Detail structure of stellar atmosphere has been done. Using binary lensing event 97-28, a very detailed study of a distant star was made.

  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] Alcock,C., et al.: "Macho Alert 95-30:First Real-Time Observation of Extended Source Effects in Gravitational Microlensing" Astrophys.J.491. 436-450 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Becker,A., et al.: "Global Microlensing Alert Network" Bull.American Astron.Soc.191. 8305-8319 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Nakamura,T., et al.: "Gravitational Waves from Coalescing Black Hole MACHO Binaries" Astrophys.J.487. L139-L142 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Chiba,T., et al.: "Cosmology with x-matter" Mon.Not.R.astr.soc.289. L5-L9 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 中村 卓史: "マッチョは宇宙のダ-クマタ-か?" 日本物理学会誌. 52. 843-847 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Nakamura,T., et al.: "The Minimum Total Mass of MACHO's and Halo Models of the Galaxy" Astrophys.J.473. L99-L102 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Muraki, Y.: "Moa Project in New Zealand" Proc.2nd Int.Conf.on Gravitational Microlensing Surveys, Paris. 359-367 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kan-ya, Y., et al.: "Microlensing and Halo Models of the Galaxy" Publ.Astron.Soc.Japan. 48. 479-487 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Uehara, H., et al.: "Fragmentation of the Primordial Gas Clouds and the Lower Limit on the Mass of the First Stars" Astrophys.J.473. L95-L98 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Nakamura, T., et al.: "The Minimum Total Mass of MACHO's and Halo Models of the Galaxy" Astrophys.J.473. L99-L102 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Nakamura, T.: "Is MACHO Cosmic Dark Matter ?" Publ.Phys.Soc.Japan. 52. 843-847 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yock, P.C.M., and J.Hearnshaw: "The MOA Project" Sky and Space. 10. 6-14 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Nakamura, T., et al.: "Gravitational Waves from Coalescing Black Hole" Astrophys.J.487. L139-L142 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Becler, A., et al.: "Global Microlensing Alert Network" Bull.American Astron.Soc.191. 8305-8319 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Alcock, C., et al.: "MACHO Alert 95-30 : First Real-Time Observation of Extended Source Effects in Gravitational Microlensing" Astrophys.J.491. 436-450 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Bond, I.A., et al.: "Search by MOA for Microlensing Events towards the Magellanic Clouds" Proc.4th Int.Conf.on Gravitational Microlensing, Paris. (in press). (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yock, P.C.M., et al.: "Future Plans for MOA" Proc.4th Int.Conf.on Gravitational Microlensing, Paris. (in press). (1998)

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 1999-03-16  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi