发表机构
Center for Cosmology and Computational Astrophysics, Institute for Advanced Study in Physics, Zhejiang University; Institute of Astronomy, School of Physics, Zhejiang University（浙江大学高等物理研究院宇宙学与计算天体物理学中心; 浙江大学物理学院天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出丝臂节点系统（FANS）作为新探针，通过测量丝臂绕节点的缠绕方向和幅度检验宇宙手征性，发现数据与宇称对称一致，且螺旋性随时间减小。
AI 中文摘要
我们定义了丝臂节点系统（FANS），这是一类新的宇宙网天体，由连接到共同节点的多条丝状臂组成，并利用其几何结构构建了基于天体的宇宙手征性检验。以宇宙网节点作为自然参考点，FANS跨越约60 Mpc/h的特征尺度，从而可以直接测量其臂绕节点的相干缠绕。我们将宇宙螺旋性定义为这种缠绕的幅度，并将其手征性定义为顺时针（CW）或逆时针（CCW）的符号方向。我们进一步引入了一种轴条件外在估计器，用于搜索手征性场的相干三维轴向模式的投影特征，对应于优选的缠绕轴。将这些测量应用于两个不同的SDSS丝状结构重建，并通过符号翻转零假设和27种FANS构建参数的控制变化评估其显著性，我们发现无论是全局还是围绕优选轴，都没有显著的CW或CCW缠绕偏好。因此，数据与标准LCDM宇宙学中预期的宇称对称性一致。我们还发现，宇宙螺旋性随宇宙时间减小，这一趋势可能反映了丝状臂的引力拉直效应。这些初步约束确立了FANS作为宇宙网对称性和大尺度形态的新探针，并为未来利用即将进行的巡天中更大丝状样本进行宇称检验提供了基线。
英文摘要
We define Filament-Arm Node Systems (FANS), a new class of cosmic-web objects consisting of multiple filament arms connected to a common node, and use their geometry to construct an object-based test of cosmic chirality. With the cosmic-web node providing a natural reference point, FANS span characteristic scales of ~60Mpc/h, allowing the coherent winding of their arms around the node to be measured directly. We define cosmic spirality as the amplitude of this winding and handedness as its signed clockwise (CW) or counter-clockwise (CCW) sense. We further introduce an axis-conditioned extrinsic estimator that searches for the projected signature of a coherent three-dimensional axial pattern of the handedness field, corresponding to a preferred axis of winding. Applying these measurements to two distinct SDSS filament reconstructions, and assessing their significance with sign-flip nulls and 27 controlled variations of the FANS construction parameters, we find no significant preference for CW or CCW winding, either globally or around a preferred axis. The data are therefore consistent with parity symmetry, as expected in standard LCDM cosmology. We additionally find that cosmic spirality decreases with cosmic time, a trend that may reflect the gravitational straightening of filament arms. These first constraints establish FANS as a new probe of cosmic-web symmetry and large-scale morphology and provide a baseline for future parity tests with the much larger filament samples expected from upcoming surveys.
Comments10 pages, 4 figures
