Search of dark matter by microlensing observations

通过微透镜观测寻找暗物质

• 批准号: 08044066
• 负责人: MURAKI Yasushi
• 金额: $ 11.52万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08044066/
• 关键词: cosmic dark matter; mosaic ccd camera; Large Magellanic Cloud; galactic center; brown dwarf; global network; MACHO; extra-solar planet; CCDカメラ; ダ-クマタ-; Macho; MOA

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.

一种最初由爱因斯坦提出的极其敏感的“引力微透镜”技术，正在由日本/新西兰合作的MOA在约翰山大学天文台使用，以进行各种基本测量。这项合作汇集了新西兰和日本几个机构的资源和专业知识。通过MOA参与全世界范围的南方观测站网络，美国和澳大利亚还提供了更多的专业知识和资源，这些观测站都使用微透镜技术。MOA和GMAN都利用了约翰山在纬度和经度方面的竞争优势来观测麦哲伦云。我们所得到的结论如下：1）银河系晕的组成是未知的。MOA小组发现它由<10%的低质量棕矮星组成，与其他小组一致。1998年5月，将用新的CCD照相机和改进的搜索技术进行观测。2）1997年7月24日发现一个额外的彗星。已经证实微透镜技术具有探测太阳系外行星所需的灵敏度。GMAN网络进行了24小时的观测，另一个称为PLANET的网络也发现了一个可能的行星实例，1998年5月，将在Mt.John使用一个大得多的2，400万而不是900万像素的CCD照相机，并将进行联机数据分析。预计将发现具有与我们类似的行星系统的恒星频率的统计学上重要的数据，可能能够支持生命。利用双星透镜事件97-28，对一颗遥远的星星进行了非常详细的研究。

项目成果

Nakamura,T.,et al.: "The Minumum Total Mass of MACHOs and Halo Models of the Galaxy" Astrophys.J.473. L99-L102 (1996)

Nakamura,T.,et al.：“银河系的 MACHO 和光晕模型的最小总质量”Astrophys.J.473。

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)

Uehara, H. 等人：“原始气体云的碎片和第一颗恒星质量的下限”Astrophys.J.473。

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)

Bond, I.A. 等人：“MOA 搜索麦哲伦星云的微透镜事件”Proc.4th Int.Conf.on Gravitational Microlensing，巴黎。

Yock, P.C.M., and J.Hearnshaw: "The MOA Project" Sky and Space. 10. 6-14 (1997)

Yock、P.C.M. 和 J.Hearnshaw：“MOA 项目”天空与空间。

Nakamura,T., et al.: "Gravitational Waves from Coalescing Black Hole MACHO Binaries" Astrophys.J.487. L139-L142 (1997)

Nakamura,T. 等人：“来自合并黑洞 MACHO 双星的引力波”Astrophys.J.487。