银河系的游牧民
Nomads of the Galaxy
摘要：
我们估计每个主序星可能有多达10^5个质量在10^{-8}-10 ^{-2}太阳质量范围内的致密天体，它们与银河系中的一颗主恒星没有联系。我们把这些天体称为游牧者;在文献中，这些天体的一个子集有时被称为自由浮动或流氓行星。我们对银河系游牧民数量的估计，与在恒星质量尺度、恒星质量密度极限和星际介质金属丰度之上的未束缚天体的质量函数的平滑外推是一致的。我们分析了通过银河系微透镜探测游牧民族的前景。宽视场红外巡天望远镜（WFIRST）将测量每个主序星的游牧者数量大于木星质量的约13%，相应的数量大于火星质量的约25%。像GAIA和LSST这样的全天巡天观测可以识别出比木星质量大的游牧民。我们建议在南半球安装一个覆盖大约100平方度的专用漂移扫描望远镜，通过对明亮恒星的微透镜作用，以几秒的特征光变曲线时间尺度来识别小至10^{-8}太阳质量的游牧者。
英文摘要：
We estimate that there may be up to ~10^5 compact objects in the mass range 10^{-8} -10^{-2} solar mass per main sequence star that are unbound to a host star in the Galaxy. We refer to these objects as nomads; in the literature a subset of these are sometimes called free-floating or rogue planets. Our estimate for the number of Galactic nomads is consistent with a smooth extrapolation of the mass function of unbound objects above the Jupiter-mass scale, the stellar mass density limit, and the metallicity of the interstellar medium. We analyze the prospects for detecting nomads via Galactic microlensing. The Wide-Field Infrared Survey Telescope (WFIRST) will measure the number of nomads per main sequence star greater than the mass of Jupiter to ~ 13%, and the corresponding number greater than the mass of Mars to ~25%. All-sky surveys such as GAIA and LSST can identify nomads greater than about the mass of Jupiter. We suggest a dedicated drift scanning telescope that covers approximately 100 square degrees in the Southern hemisphere could identify nomads as small as 10^{-8} solar mass via microlensing of bright stars with characteristic lightcurve timescales of a few seconds.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
