基于10年KMTNet数据库的黑洞天体测量微引力透镜研究路径
Path to Black Hole Astrometric Microlensing from 10-Year KMTNet Database
AI总结：
本文对10年KMTNet数据库中的黑洞天体测量微引力透镜信号进行费舍尔分析，提出结合光度与天体测量搜寻的计划，可在控制系统误差后测量黑洞的爱因斯坦半径、质量与距离。
AI中文摘要：
受Segev等人（2026）试点研究成功的启发，该研究将I=18等时的散差降至σ~10毫角秒（mas），本文对可能存在于10年KMTNet微引力透镜数据库中的黑洞（BHs）天体测量信号进行了费舍尔分析。受视宁度限制的地面观测仍存在大量系统误差，但假设这些系统误差可被控制，本文发现，在监测最密集的天区（约12平方度）中，以此名义精度测量的爱因斯坦半径误差σ(θ_E)约为0.5毫角秒，在额外约28平方度的天区中误差则为此值的两倍。只要碰撞参数u₀在光度识别事件可及的宽范围内（即u₀≲1.5），该精度几乎不依赖于事件峰值是否处于观测季内，不过更长的事件精度会略好。本文的分析未考虑 blending（光混），但对于大多数I≲18等、位于或接近巨星支的源而言，这是一个良好的初步近似。本文概述了一项结合光度与天体测量搜寻的实用计划，旨在识别KMTNet数据库中的孤立黑洞并测量其质量与距离。
英文摘要：
I present a Fisher analysis of the astrometric signature of black holes (BHs) that may lie in the 10-year KMTNet microlensing database, motivated by the recent success of the pilot study by Segev et al. (2026), which reduced the scatter at $I=18$ to $σ\sim 10\,$mas. Seeing-limited ground-based observations still suffer from a great deal of systematics, but under the assumption that these systematics can be controlled, I find that with this nominal precision, the Einstein radius can be measured with errors $σ(θ_{\rm E})\sim 0.5\,$mas in the most intensively monitored fields ($\sim 12\,$deg$^2$), and hence to twice that value in an additional $\sim 28\,$deg$^2$ area. This precision hardly depends on whether the peak of the event is during the observing season or not, as long as the impact parameter is within the broad range that is accessible to photometric recognition of the event, i.e., $u_0\lesssim 1.5$. However, longer events do have somewhat better precision. The analysis presented here ignores blending, but this is a good first approximation for most sources $I\lesssim 18$, which lie near or on the giant branch. I outline a practical program, combining photometric and astrometric searches, aimed at identifying isolated BHs in the KMTNet database and measuring their masses and distances.
