Probing Circumstellar Envelopes with Gravitational Microlensing

在这个项目中，将为解释在持续监测活动中发现的恒星引力微透镜事件提供理论基础和观测方法。原则上，当一个看不见但质量很大的物体从观测者和背景恒星之间经过时，这些事件可以用来“引力成像”，否则就无法分辨恒星光球和星周结构。目前的微透镜技术只有在假设正常对称的恒星光球时才有用。pi将扩展这项技术，包括涉及红巨星的微透镜事件。后者具有高度不对称的大气结构、风以及包层大小、速度和密度的变化。这项技术也可以用于对附近其他正常星系（如M31）和活动星系核中的透镜事件进行分类。该项目由美国国家科学基金会恒星天文学和天体物理学项目（AST/SAA）提供资金。

ABSTRACTIgnace, Richard"Probing Circumstellar Envelopes with Gravitational Microlensing"AST-9986915In this project a theoretical basis and observational methodology will be developed for interpreting stellar gravitational microlensing events that are discovered in the course of ongoing monitoring campaigns. Such events in principle can be used to 'gravitationally image' otherwise unresolvable stellar photospheric and circumstellar structures when an invisible but massive object passes between the observer and a background star. Current microlensing techniques are useful only by assuming normal symmetrical stellar photospheres. The PIs will extend the technique to include microlensing events that involve red giant stars. The latter have highly asymmetrical atmospheric structure, winds, and variations in envelope size, velocity and density. The technique developed also may be useful in categorizing lensing events in the nuclei of other nearby normal galaxies such as M31 and active galactic nuclei.Funding for this project was provided by the NSF program for Stellar Astronomy & Astrophysics (AST/SAA).