标题： 银河系暗物质模型的微透镜效应 显示英文标题

标题： Microlensing of dark matter models in the Milky Way

摘要： 我们利用来自OGLE巡天观测的五年微透镜数据，研究了作为暗物质（DM）候选体的原始黑洞（PBH）丰度的限制条件。 虽然OGLE观测到的大约2000年左右的大多数微透镜事件可以通过褐矮星、主序星和致密遗迹等恒星种群很好地解释，但六个超短时间尺度事件（大约0.1 - 0.3天）可能预示着PBH的存在。 在先前采用Navarro-Frenk-White (NFW)暗物质轮廓线的研究基础上，我们研究了其他暗物质晕模型——特别是Einasto和Burkert轮廓线——如何影响微透镜效应预测以及PBH丰度的限制条件。 我们以主序星事件率作为观测基准，计算了这两个轮廓线的微透镜事件率差值。 我们的结果表明，Einasto 和 Burkert 轮廓均未重现主序恒星事件的分布，但两者均可对超黑洞质量 $M_{\mathrm{PBH}} \sim 10^{-5} M_\odot$ 的超短时间尺度事件提供可行的解释。 在 OGLE 数据集中未观测到任何超黑洞的零假设下，使用泊松似然分析，我们推导出 $f_{\mathrm{PBH}}$ 的 95% CL 上限，发现与 NFW 情况相比，Einasto 和 Burkert 轮廓下的约束明显放宽。 这些结果强调了超黑洞约束对假设的暗物质晕结构的敏感性，并强调了准确模拟银河系内密度轮廓对于稳健评估超黑洞暗物质情景的重要性。 显示英文摘要

摘要： We investigate constraints on the abundance of primordial black holes (PBHs) as dark matter (DM) candidates using five years of microlensing data from the OGLE survey. While the majority of OGLE's $\sim 2000$ microlensing events are well-explained by stellar populations such as brown dwarfs, main-sequence stars, and compact remnants, a subset of six ultrashort-timescale events ($t_E \sim 0.1 - 0.3$ days) may signal the presence of PBHs. Building upon prior work that adopted the Navarro-Frenk-White (NFW) DM profile, we examine how alternative DM halo models -- specifically the Einasto and Burkert profiles -- affect microlensing predictions and the constraints on PBH abundance. We computed differential microlensing event rates for both profiles, using the main-sequence star rate as an observational benchmark. Our results show that neither the Einasto nor Burkert profiles reproduce the distribution of main-sequence star events, yet both allow for viable explanations of the ultrashort-timescale events with PBH masses $M_{\mathrm{PBH}} \sim 10^{-5} M_\odot$. Using a Poisson likelihood analysis under the null hypothesis that no PBH is observed in OGLE dataset, we derive 95\% C.L. upper bounds on $f_{\mathrm{PBH}}$, finding that the constraints are significantly relaxed under the Einasto and Burkert profiles compared to the NFW case. These results underscore the sensitivity of PBH constraints to the assumed DM halo structure and highlight the importance of accurately modeling the inner Galactic density profile to robustly assess PBH dark matter scenarios.