AI 中文总结
本研究分析Cosmicflows-4星表的大尺度相干运动，发现其与ΛCDM模型大体一致，仅存在局域且依赖观测窗的异常特征，需进一步模拟检验。
AI 中文摘要
我们研究Cosmicflows-4（CF4）及其组成星表中的相干运动，采用对数距离径向速度估计器，在不重叠的径向区间内拟合单极矩与偶极矩。对于每个样本，普朗克2018年ΛCDM模型的预测结果涵盖了实际位置、统计权重、速度协方差及测量协方差。在延伸至300h⁻¹Mpc的六个区间中，全样本与ΛCDM模型大体一致，偶极偏差和联合偏差分别为2.29σ和2.36σ。最强的局域特征出现在120–160h⁻¹Mpc处，此处|V_dip|=628±82km/s，偶极偏差达3.40σ；该过量集中于负超星系X方向，且与观测窗高度相关。TFR和6dFGS倾向于更大的偶极，而SDSS和SN则倾向于更小的偶极。移除6dFGS后，上限区间的偶极偏差降至1.56σ；移除SN后，偏差升至3.77σ。不过，当纳入协方差时，SN与6dFGS的偶极仍相互一致。SDSS在160h⁻¹Mpc范围内与ΛCDM模型一致，但在更大半径处呈现单独上升，其显著性取决于单极及共享距离标度协方差的处理方式。总体而言，CF4在其全部径向范围内未表现出均匀的异常运动，而是包含局域且依赖观测窗的特征，需通过选择匹配的模拟星表及相关校准不确定性进行检验。
英文摘要
We study coherent flows in Cosmicflows-4 (CF4) and its constituent catalogs. We fit monopole and dipole moments in nonoverlapping radial bins using a log-distance radial-velocity estimator. For each sample, the Planck 2018 $Λ$CDM prediction accounts for the actual positions, statistical weights, velocity covariance, and measurement covariance. Across six bins extending to $300,h^{-1},\mathrm{Mpc}$, the All Individual sample is broadly consistent with $Λ$CDM, with dipole and joint deviations of $2.29σ$ and $2.36σ$. The strongest localized feature occurs at $120$--$160,h^{-1},\mathrm{Mpc}$, where $|V_{\rm dip}|=628\pm82,\mathrm{km,s^{-1}}$ and the dipole deviation reaches $3.40σ$. The excess is concentrated toward negative supergalactic X and depends strongly on the survey window. TFR and 6dFGS favor larger dipoles, while SDSS and SN favor smaller ones. Removing 6dFGS reduces the upper-bin dipole deviation to $1.56σ$, while removing SN raises it to $3.77σ$. Nevertheless, the SN and 6dFGS dipoles remain mutually consistent when their covariance is included. SDSS is consistent with $Λ$CDM through $160,h^{-1},\mathrm{Mpc}$ but shows a separate rise at larger radii whose significance depends on the treatment of the monopole and shared distance-scale covariance. Overall, CF4 does not show uniformly anomalous motion across its full radial range. Instead, it contains localized and window-dependent features that should be tested with selection-matched mock catalogs and correlated calibration uncertainties.
Comments21 pages, 8 figures
