Photometric Microlens Parallaxes with the Space Interferometry Mission
Photometric Microlens Parallaxes with the Space Interferometry Mission
复制标题
光度微透镜视差与空间干涉测量任务
DOI：
10.1086/307843
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Salim
中科院分区：
文献类型：
--
作者：
A. Gould;S. Salim
微透镜事件的天体测量原则上可以确定单个事件的“视差”E和“自行”μ，这（与爱因斯坦时间尺度tE相结合）反过来又产生了透镜的质量，距离和横向速度。然而，我们表明，视差测量一般是几个数量级的精确度比自行测量。幸运的是，空间干涉测量使命任务（SIM）的天体测量同时也是光度测量，由于SIM将位于太阳轨道，这使得SIM可以用作经典（光度）视差卫星。我们表明，SIM光度测量的精度与其天体测量自行测量的精度相当。对于I = 15的核球星，通过5小时的观测就可以得到质量、距离和横向速度的精确度约为5%的完整解，比类似精度的纯天体测量解短100 ~ 10，000倍。因此，只需要几百个小时的SIM观测，就可以直接测量凸起和内部圆盘（包括黑暗和发光物体）的质量函数。
Astrometric measurements of microlensing events can in principle determine both the "parallax" E and the "proper motion" μ of an individual event, which (combined with the Einstein timescale tE) in turn yield the mass, distance, and transverse velocity of the lens. We show, however, that the parallax measurements are generically several orders of magnitude less precise than the proper-motion measurements. Fortunately, astrometric measurements by the Space Interferometry Mission (SIM) are simultaneously photometric measurements, and since SIM will be in solar orbit, these allow SIM to be used as a classical (photometric) parallax satellite. We show that SIM photometric parallaxes are of precision comparable to that of its astrometric proper-motion measurements. For I = 15 bulge stars, complete solutions with ~5% accuracy in mass, distance, and transverse velocity can be obtained from about 5 hr of observation, 100-10,000 times shorter than would be required for a purely astrometric solution of similar precision. Thus, it should be possible to measure directly the mass functions of both the bulge and the inner disk (including both dark and luminous objects) with only a few hundred hours of SIM observations.