MACHO Parallaxes from a Single Satellite
MACHO Parallaxes from a Single Satellite
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来自单个卫星的 MACHO 视差
DOI：
10.1086/187779
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
A. Gould
中科院分区：
文献类型：
--
作者：
A. Gould
大质量致密天体（Machos）目前的发现率大大高于已知恒星种群标准模型的预期。为了确定它们是由于已知群体的非标准分布还是由于迄今未知的（“黑暗”）群体，人们必须获得有关单个事件的更多信息。天基卫星可能是提取更多信息的最佳工具。对于主序，由单个卫星进行的视差测量导致四重简并：$\tilde v$的两个可能值和垂直于投影的卫星-地球矢量的运动分量的两个可能符号。人们认为，需要第二颗卫星来打破这种简并。我表明，卫星和地球之间的速度差允许一个部分或完全打破简并使用一个单一的卫星。对于大多数Macho事件，可以测量$\tilde v$和$\tilde r_e$。对于某些情况，也可以测量$\Phi$。拟议中的空间红外望远镜每年可以测量$\sim 100$的射电望远镜时间为$\sim 400\，$hr。
Massive Compact Objects (Machos) are currently being discovered at substantially higher rates than would be expected from standard models of known stellar populations. To determine whether they are due to non-standard distri- butions of known populations or to a heretofore unknown (`dark') population, one must acquire more information about the individual events. Space-based parallaxes are potentially the best tool for extracting additional information. To leading order, parallax measurements by a single satellite result in a four- fold degeneracy: two possible values of $\tilde v$ and two possible signs for the component of motion perpendicular to the projected satellite-Earth vector. It had been believed that a second satellite would be required to break this degeneracy. I show that the velocity difference between the satellite and the Earth allows one to partially or totally break the degeneracy using a single satellite. For most Macho events it is possible to measure $\tilde v$ and $\tilde r_e$. For some it is also possible to measure $\Phi$. The proposed Space Infrared Telescope could measure $\sim 100$ parallaxes per year by applying $\sim 400\,$hr of telescope time.