发表机构
Duke University; Bar-Ilan University; University of Helsinki; Space Telescope Science Institute; Johns Hopkins University（杜克大学; 巴伊兰大学; 赫尔辛基大学; 太空望远镜科学研究所; 约翰斯·霍普金斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过IllustrisTNG模拟量化哈勃流模型偏差，开发基于模拟的H₀推断方法，结合室女座星系团TRGB样本修正偏差后得到H₀测量值，为星系团内落测量提供解释框架。
AI 中文摘要
星系退行速度通常被用于测量哈勃常数H₀，而本动速度被当作随机噪声处理。不过在大质量星系团周围，这些运动可由中心暗物质晕的引力势预测，因此可对其建模而非取平均。过往分析依赖距离-内落速度关系的解析近似，其准确性尚未用真实宇宙学模拟检验。我们使用IllustrisTNG模拟中的暗物质晕量化几种常用哈勃流模型的偏差与精度，发现广泛使用的拟合函数会系统性低估H₀，而完整解析解可降低但无法消除这些偏差。我们开发一种基于模拟的H₀推断方法，并将其应用于室女座星系团周围的TRGB距离样本，得到H₀=74.4±2.9和73.4±3.9 km s⁻¹ Mpc⁻¹（统计误差），分别对应次内落和主内落模型；根据TNG晕校准的偏差修正后，这些测量值将H₀提升至81.6±7.8和87.3±8.8 km s⁻¹ Mpc⁻¹（统计+系统误差），其中次内落模型在室女座模拟样本中的偏差最小。我们还表明，统计误差主要由内落模型周围的残余速度弥散主导，而系统误差主要由结构到共动参考系的转换和暗物质晕总体方差主导。这些结果建立了用于解释星系团内落测量的框架，并解释了过往H₀推断中的趋势。
英文摘要
Galaxy recession velocities are commonly used to measure the Hubble constant, $H_0$, with peculiar velocities treated as random noise. Around massive clusters, however, these motions can be predicted by the gravitational potential of the central halo, allowing them to be modeled rather than averaged over. Past analyses relied on analytic approximations for the distance-infall-velocity relation, whose accuracy has not been tested using realistic cosmological simulations. We use halos from the IllustrisTNG simulation to quantify the bias and precision of several commonly used Hubble-flow models. We find that widely used fitting functions systematically underestimate $H_0$, whereas the full analytical solution reduces but does not eliminate these biases. We develop a simulation-based method to infer $H_0$ and apply it to TRGB distance samples around the Virgo Cluster. We find $H_0=74.4\pm 2.9$ and $73.4\pm 3.9$ km s$^{-1}$ Mpc$^{-1}$ (stat) for the minor and the major infall models, respectively. Correcting for the bias calibrated on TNG halos, these measurements raise the value of $H_0$ to $81.6 \pm 7.8$ and $87.3 \pm 8.8$ km s$^{-1}$ Mpc$^{-1}$ (stat+sys), where the minor infall model has the smallest bias from the Virgo mocks. We show that statistical errors are dominated by the residual velocity scatter around the infall model, while systematic errors are dominated by the transformation to the structure's comoving frame and halo population variance. These results establish a framework for interpreting cluster infall measurements and explain trends in previous $H_0$ inferences.
Comments23 pages, 13 figures
