发表机构
Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut; Sydney Institute for Astronomy (SIfA), The University of Sydney; Donald Bren School of Information and Computer Sciences, University of California, Irvine; Astronomical Observatory, University of Warsaw; Astrophysics Division, National Centre for Nuclear Research（海德堡大学天文中心，天文计算研究所; 悉尼大学天体物理研究所; 加州大学欧文分校唐纳德布伦信息与计算机科学学院; 华沙大学天文台; 国家核研究中心天体物理学部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对盖亚DR4，我们构建模拟微透镜事件样本，利用嵌套采样测试推断工具，预测了322个天体测量事件，并评估了残骸透镜搜寻能力，公开了数据集和工具包。
AI 中文摘要
欧空局的天体测量空间任务盖亚（Gaia）凭借其全天覆盖以及同步的天体测量和光度观测，在微透镜研究方面具有独特优势。在盖亚数据发布4（DR4）中，天体测量时间序列将首次发布，为孤立恒星残骸搜寻提供丰富的数据集。为迎接DR4，我们准备了拟合光度和一维天体测量数据的工具。我们测试了利用类盖亚观测恢复真实事件参数和总体分布的能力。我们构建了一个模拟盖亚DR4设计的微透镜事件巡天样本。这些事件使用专门的银河系模拟生成，以提供对恒星和暗透镜产出的现实预期。对于选定的事件，我们使用astromet包，按照盖亚的扫描规律和精度模拟了观测。此类模拟对于解释即将到来的数据是必要的；它们还能在已知真实值的情况下测试推断工具。我们使用嵌套采样推断完整的后验分布，并将其与真实透镜参数进行比较。我们的模拟预测，有$322 \pm 70$个微透镜事件的天体测量信号超过盖亚的精度阈值；其中$209 \pm 57$个具有可探测的光度信号。在这些事件中，分别有$82 \pm 9$个和$49 \pm 7$个具有残骸透镜。为评估盖亚在约束残骸质量分布方面的能力，我们对该样本中的$49$个事件进行了建模。我们恢复了大多数事件的真实爱因斯坦时间和半径。微透镜视差测量与真实值一致，但存在不确定性，限制了质量测定。我们建议关注具有明亮源或异常拟合的事件，以优化暗透镜搜寻。我们公开了模拟的盖亚时间序列数据集，以及一个用于处理数据格式、拟合模型和可视化结果的工具包仓库。
英文摘要
ESA's astrometric space mission Gaia is uniquely positioned for microlensing studies thanks to its all-sky coverage and simultaneous astrometric and photometric observations. In Gaia Data Release 4 (DR4), astrometric time series will be published for the first time, providing a rich dataset for isolated stellar remnant searches. In anticipation of DR4, we prepared tools for fitting photometric and 1D astrometric measurements. We tested the recovery of true event parameters and population distributions with Gaia-like observations. We created a mock survey of microlensing events mirroring Gaia DR4's design. The events were generated using dedicated Galactic simulations to provide realistic expectations on stellar and dark lens yields. For selected events, we simulated observations following Gaia's scanning law and precision, using the astromet package. Such simulations are needed to interpret forthcoming data; they also enable testing inference tools with known ground truth. We used nested sampling to infer full posterior distributions and compare them with the true lens parameters. Our simulation predicts $322 \pm 70$ microlensing events with astrometric signals above Gaia precision thresholds; $209 \pm 57$ of them have detectable photometric signals. Among those, $82 \pm 9$ and $49 \pm 7$, respectively, have remnant lenses. To assess Gaia's capabilities in constraining remnant mass distributions, we modelled $49$ events from this sample. We recovered the true Einstein times and radii for most events. Microlensing parallax measurements are consistent with true values but uncertain, limiting mass determination. We recommend focusing on events with bright sources or anomalous fits to optimize dark lens searches. We make available the mock Gaia time-series dataset, as well as a toolkit repository for working with the data format, fitting models, and visualizing results.
Comments14 pages, 9 figures, accepted for publication in A&A
