The pairwise velocity generating function $G$ has deep connection with both the pairwise velocity probability distribution function and modeling of redshift space distortion (RSD). Its implementation into RSD modeling is often faciliated by expansion into series of pairwise velocity moments $\langle v_{12}^n\rangle$. Motivated by the logrithmic transformation of the cosmic density field, we investigate an alternative expansion into series of pairwise velocity cumulants $\langle v_{12}^n\rangle_c$ . We numerically evaluate the convergence rate of the two expansions, with three $3072^3$ particle simulations of the CosmicGrowth N-body simulation series. (1) We find that the cumulant expansion performs significantly better, for all the halo samples and redshifts investigated. (2) For modeling RSD at $k_{\|}<0.1 h$ Mpc$^{-1}$, including only the $n=1,2$ cumulants is sufficient. (3) But for modeling RSD at $k_\parallel=0.2 h$ Mpc$^{-1}$, we need and only need the $n=1,2,3,4$ cumulants. These results provide specific requirements on RSD modeling in terms of $m$-th order statistics of the large scale strucure.
A new constraint on the $y$-distortion with FIRAS: implications for feedback models in galaxy formation and cosmic shear measurements
School of Physics and Astronomy, Cardiff University（卡迪夫大学物理与天文学院）；Kavli Institute for Cosmology Cambridge（剑桥宇宙学卡弗里研究所）；Kavli Institute for Particle Astrophysics and Cosmology, Stanford University（斯坦福大学粒子天体物理与宇宙学卡弗里研究所）；SLAC National Accelerator Laboratory（史拉夫国家加速器实验室）；Department of Physics, Stanford University（斯坦福大学物理系）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Department of Astronomy, Columbia University（哥伦比亚大学天文学系）；Department of Physics, Columbia University（哥伦比亚大学物理系）；Institute of Astronomy（天文学研究所）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo（东京大学宇宙物理数学卡弗里研究所（WPI）、东京大学高级研究院（UTIAS））；Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学数据驱动发现中心、宇宙物理数学卡弗里研究所（WPI）、东京大学高级研究院）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；Department of Astrophysical Sciences, Princeton University（普林斯顿大学天体物理学科学系）
Systematic Spectral Distortion from Digital Whitening in Radio Telescopes and Implications for 21 cm Cosmology
California Institute of Technology（加州理工学院）；Owens Valley Radio Observatory, California Institute of Technology（欧文斯谷射电天文台，加州理工学院）；Arizona State University（亚利桑那州立大学）
