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.

一种极其灵敏的“引力微透镜”技术，最初是由爱因斯坦提出的，由日本和新西兰合作的MOA在约翰山大学天文台使用，以进行各种基本测量。此次合作汇集了新西兰和日本几家机构的资源和专业知识。通过MOA参与一个使用微透镜技术的全球南方天文台网络，美国和澳大利亚的专业知识和资源也得到了补充。该网络被称为GMAN。MOA和GMAN都利用约翰山在纬度和经度方面的竞争优势来观测麦哲伦星云。我们的发现如下：1)银河系光晕的组成是未知的。MOA小组发现它由小于10%的低质量棕矮星组成，与其他小组一致。1998年5月，将使用新的CCD相机和改进的搜索技术进行观测。2) 1997年7月24日发现一颗额外的木星。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，另一个名为PLANET的网络发现了一个可能存在行星的例子。同样在1998年5月，约翰山将使用一个更大的CCD照相机，有2400万而不是900万像素，数据分析将在网上进行。预计将会发现具有与地球类似的行星系统的恒星频率的统计数据，这些恒星可能有能力支持生命。3)绘制了恒星大气的详细结构。利用双透镜事件97-28，对一颗遥远的恒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。