Microlens Parallaxes with SIRTF
Microlens Parallaxes with SIRTF
复制标题
SIRTF 的微透镜视差
DOI：
10.1086/306981
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Gould
中科院分区：
文献类型：
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作者：
A. Gould
空间红外望远镜设施（SIRTF）将以~0.1 Au yr-1的速度偏离地球。因此，从卫星和地球上看，微透镜事件将具有不同的特征。从这个差值，原则上可以测量出透镜投射到观察者平面上的横向速度ν τ。由于不同的星群（星盘、晕、大麦哲伦云）的ν α有非常不同的值，这样的测量可以帮助确定透镜的位置，从而确定透镜的性质。我表明，古尔德以前开发的方法来测量这种卫星反射完全失败的情况下，SIRTF：它是压倒性的退化所产生的事实，地球和卫星观测是在不同的带通。我开发了一种新方法，允许在不同的带通中进行观察，但又消除了所有简并。该方法将“视差不对称”的纯地面测量与事件在地球和卫星上达到峰值的时间之间的延迟测量相结合。实际上，视差不对称性决定了地球-太阳方向的ν θ分量，而延迟时间则测量了地球轨道方向的ν θ分量。
The Space Infrared Telescope Facility (SIRTF) will drift away from the Earth at ~0.1 AU yr-1. Microlensing events will therefore have different characteristics as seen from the satellite and the Earth. From the difference it is possible in principle to measure ν̃, the transverse velocity of the lens projected onto the observer plane. Since ν̃ has very different values for different populations (disk, halo, Large Magellanic Cloud), such measurements could help identify the location, and hence the nature, of the lenses. I show that the method previously developed by Gould for measuring such satellite parallaxes fails completely in the case of SIRTF: it is overwhelmed by degeneracies that arise from fact that the Earth and satellite observations are in different bandpasses. I develop a new method that allows for observations in different bandpasses and yet removes all degeneracies. The method combines a purely ground-based measurement of the "parallax asymmetry" with a measurement of the delay between the time the event peaks at the Earth and satellite. In effect, the parallax asymmetry determines the component of ν̃ in the Earth-Sun direction, while the delay time measures the component of ν̃ in the direction of the Earth's orbit.