RUI: Statistical Modeling of Microlens Masses

RUI：微透镜质量的统计建模

• 批准号: 0205754
• 负责人: William Heacox
• 金额: $ 3.49万
• 依托单位: University of Hawaii at Hilo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0205754&HistoricalAwards=false
• 关键词: RUI; Statistical; Modeling; Microlens; Masses

AST-0205754HeacoxDr. William Heacox will analyze gravitational microlens survey data in the current literature in order to deduce the mass distributions of the objects causing the lensing, and thus help characterize their natures. Microlensing is a promising means of detecting otherwise undetectable planetary- to stellar-mass objects in such locations as the halo of our galaxy, where a large amount of dark matter of unknown nature is known to exist. In a typical microlens survey, a few million stars in the Large Magellanic Cloud are monitored periodically to detect the optical amplification caused by gravitational lensing when a Galactic halo object (the lens) passes nearly in front of a background star (the source). While the resulting amplification amplitude depends upon lens mass, it also depends upon such unknowable quantities as the relative velocity of lens and source, and the distance of closest encounter of the lens to the line-of-sight to the source. This complication has prevented accurate estimates of lens masses, so that the observation of a few tens of microlenses has not greatly aided in the identification of halo dark matter. Dr. Heacox' research consists of the application of sophisticated statistical modeling techniques to the entire set of observed microlenses in a survey, in order to determine the statistical distribution of lens masses (rather than the masses of individual lenses). The method uses all that is knowable about the kinematics (velocities, distances) of lens and source populations, together with the set of observed microlens parameters, to infer all that can be deduced about the mass distribution of the underlying population causing the lensing. In application to the Galactic halo microlenses, the result should be the first credible estimate of the mass distribution of the halo dark matter, and a concomitant increase in our understanding of the nature of this material. The nature of dark matter in the Universe is one of the outstanding problems in modern astronomy; a better understanding of the component in our galaxy will be a useful first step in determining what most of the Universe is made of. This award is made under the auspices of the Research in Undergraduate Institutions (RUI) program at NSF.***

AST-0205754HEACOXDR。威廉·希科克斯（William HeaCox）将分析当前文献中的重力微滴定数据，以推断引起镜头的物体的质量分布，从而有助于表征其本性。 微透明是一种有前途的方法，可以在我们的银河系中检测到其他无法检测到的行星至恒星质量物体，在我们的银河系中，已知存在大量未知性质的暗物质。 在典型的Microlens调查中，定期监测大麦芽云中的几百万颗恒星，以检测当时银河晕对象（镜头）几乎在背景恒星（来源）的前面传递时，由重力透镜引起的光学扩增。 虽然所得的扩增幅度取决于透镜质量，但它也取决于诸如镜头和源的相对速度，以及镜头与镜头视线与源的最接近距离的距离。 这种并发症阻止了对晶状体质量的准确估计，因此观察几十微粒并不能在鉴定光环暗物质的鉴定方面得到极大的帮助。 HeaCox博士的研究包括在调查中将复杂的统计建模技术应用于整个观察到的微镜，以确定晶状体质量的统计分布（而不是单个透镜的质量）。 该方法使用有关晶状体和源群体的运动学（速度，距离）以及一组观察到的微滴参数的所有知识，以推断所有可以推论的有关镜头质量的质量分布的质量分布。 在应用银河光环微晶状体时，结果应是对光晕暗物质质量分布的第一个可靠估计，以及我们对该材料本质的理解的同时增加。 宇宙中暗物质的本质是现代天文学中的杰出问题之一。更好地理解我们银河系中的组件将是确定大多数宇宙所构成的有用的第一步。 该奖项是根据NSF的本科机构（RUI）计划的主持。***