AI 中文总结
本研究利用冷暗物质（CDM）框架下的暗物质亚晕，通过双源重建建模拟合HS~0810+2554的8个射电图像，成功解释其位置异常，拟合优度显著提升，无需引入非标准暗物质情景。
AI 中文摘要
冷暗物质（CDM）情景下，预测星系晕中会大量存在自束缚暗物质（DM）亚晕。这些子结构可在强引力透镜中留下可观测痕迹，且已被证实能解释多重成像系统中的流量比异常和位置异常。本文中，我们利用DM亚晕解决甚长基线干涉测量观测到的HS 0810+2554的两个射电四重像的图像位置异常。我们采用椭圆幂律主透镜结合数值模拟得到的CDM亚晕群来建模透镜，并执行双源重建以同时拟合全部8个射电图像。我们发现，质量低于10^6 M⊙的亚晕引起的天体测量偏移小于测量不确定度，而质量更大的亚晕可自然产生所需的毫角秒级扰动，且不会显著改变全局透镜构型。纳入CDM亚晕后，拟合优度从纯主透镜的χ²=60.38提升至χ²=1.61。我们的结果表明，HS~0810+2554的位置异常可在CDM框架内得到解释，本身并不一定需要模糊DM或主透镜角复杂度等非标准情景；相反，它们为CDM预测的亚晕群提供了清晰且可检验的表现形式。
英文摘要
Self-bounded dark matter (DM) subhalos are predicted to populate galactic halos in great abundance in the Cold Dark Matter (CDM) scenario. These substructures can leave observable imprints in strong gravitational lensing and have shown the ability to account for flux-ratio and position anomalies in multiply imaged systems. In this paper, we utilize the DM subhalos to address the image position anomalies of the two radio quads of HS 0810+2554 observed with the Very Long Baseline Interferometry. We model the lens using an elliptical power-law macro-lens supplemented by a population of CDM subhalos from numerical simulations and perform a dual-source reconstruction to fit all eight radio images simultaneously. We find that subhalos below $10^{6}M_\odot$ induce astrometric shifts smaller than the measurement uncertainties, whereas more massive subhalos naturally generate the required milliarcsecond perturbations without significantly altering the global lens configuration. Including CDM subhalos improves the fit from $χ^2=60.38$ for the pure macro-lens to $χ^2=1.61$. Our results show that the position anomalies of HS~0810+2554 can be explained within the CDM framework and do not by themselves necessarily require non-standard scenarios like fuzzy DM or angular complexity in the macro-lens. Instead, they provide a sharp and testable manifestation of the subhalo population predicted by CDM.
Comments13 pages, two columns, 1 table, 5 figures
