Next-Gen modelling for high-precision exoplanet microlensing surveys

没有与任何恒星绑定，漂浮在星际介质中的系外行星的丰度，被称为自由漂浮行星（FFPs），目前还没有得到很好的约束。直接成像提供了几个确认的FFP，但不允许我们提取FFP统计数据。通过引力微透镜方法，由于该方法对透镜通量的不变性，我们更容易发现这些虚幻的物体。尽管如此，微透镜调查也只提供了少数候选者。这是由于FFPs的质量相对较小，与行星质量相似，微透镜事件的时间尺度也相应较短。即将到来的大型天文巡天望远镜（LSST）和宽视场红外巡天望远镜（WFIRST）等巡天项目将提供有关ffp星系数量的前所未有的详细信息，并允许进行ffp质量测量等特性，同时也提供对行星形成的洞察。为此，该项目将专注于为LSST和WFIRST开发FFP搜索策略。这将涉及开发更严格的微透镜光学深度计算，以及研究在各自望远镜技术的情况下FFP质量测量的潜力。

The abundance of exoplanets not bound to any star, floating in the interstellar medium, known asfree floating planets (FFPs) is currently poorly constrained. Direct imaging has provided severalconfirmed FFPs, but does not allow us to extract FFP statistics. Via the gravitational microlensingmethod, we are more likely to find these illusive objects due to the methods invariability to the lensflux. Nonetheless, microlensing surveys have also provided only a handful of candidates. This is dueto the comparatively small masses of FFPs, on similar scales to planet masses, and thecorrespondingly short timescale of microlensing events. Upcoming surveys such as by the LargeSynoptic Survey Telescope (LSST) and the Wide Field Infrared Survey Telescope (WFIRST) couldprovide unprecedented detail on the galactic population of FFPs and also allow for properties such asFFP mass measurements to be made, also providing insight into planetary formation. To this end, theproject will focus on developing an FFP search strategy for the LSST and WFIRST. This will involvedeveloping more a more rigorous calculation of the microlensing optical depth, as well asinvestigating the potential for FFP mass measurements given the technology of the respectivetelescopes.