Kriging interpolating cosmic velocity field

	Kriging interpolating cosmic velocity field
	Yu, Yu1 ; Zhang, Jun 2,3; Jing, Yipeng 2,3; Zhang, Pengjie 1,2,3
刊名	PHYSICAL REVIEW D
	2015-10-27
卷号	92 期号:8 页码:1
英文摘要	Volume-weighted statistics of large-scale peculiar velocity is preferred by peculiar velocity cosmology, since it is free of the uncertainties of galaxy density bias entangled in observed number density-weighted statistics. However, measuring the volume-weighted velocity statistics from galaxy (halo/simulation particle) velocity data is challenging. Therefore, the exploration of velocity assignment methods with well-controlled sampling artifacts is of great importance. For the first time, we apply the Kriging interpolation to obtain the volume-weighted velocity field. Kriging is a minimum variance estimator. It predicts the most likely velocity for each place based on the velocity at other places. We test the performance of Kriging quantified by the E-mode velocity power spectrum from simulations. Dependences on the variogram prior used in Kriging, the number n(k) of the nearby particles to interpolate, and the density n(P) of the observed sample are investigated. First, we find that Kriging induces 1% and 3% systematics at k similar to 0.1h Mpc(-1) when n(P) similar to 6 x 10(-2) (h(-1) Mpc)(-3) and n(P) similar to 6 x 10(-3) (h(-1) Mpc)(-3), respectively. The deviation increases for decreasing nP and increasing k. When n(P) less than or similar to 6 x 10(-4) (h(-1) Mpc)(-3), a smoothing effect dominates small scales, causing significant underestimation of the velocity power spectrum. Second, increasing nk helps to recover small-scale power. However, for n(P) less than or similar to 6 x 10(-4) (h(-1) Mpc)(-3) cases, the recovery is limited. Finally, Kriging is more sensitive to the variogram prior for a lower sample density. The most straightforward application of Kriging on the cosmic velocity field does not show obvious advantages over the nearest-particle method [Y. Zheng, P. Zhang, Y. Jing, W. Lin, and J. Pan, Phys. Rev. D 88, 103510 (2013)] and could not be directly applied to cosmology so far. However, whether potential improvements may be achieved by more delicate versions of Kriging is worth further investigation.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics ; Physics, Particles & Fields
研究领域[WOS]	Astronomy & Astrophysics ; Physics
关键词[WOS]	STRUCTURE GROWTH ; REDSHIFT SPACE ; DARK ENERGY ; STATISTICS ; ACCELERATION ; DISTORTIONS ; GALAXIES ; PROBE
收录类别	SCI
语种	英语
WOS记录号	WOS:000363529100003
公开日期	2016-01-19
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/28382]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 2.Shanghai Jiao Tong Univ, Dept Phys & Astron, Ctr Astron & Astrophys, Shanghai 200240, Peoples R China 3.Shanghai Jiao Tong Univ, IFSA Collaborat Innovat Ctr, Shanghai 200240, Peoples R China
推荐引用方式 GB/T 7714	Yu, Yu,Zhang, Jun,Jing, Yipeng,et al. Kriging interpolating cosmic velocity field[J]. PHYSICAL REVIEW D,2015,92(8):1.
APA	Yu, Yu,Zhang, Jun,Jing, Yipeng,&Zhang, Pengjie.(2015).Kriging interpolating cosmic velocity field.PHYSICAL REVIEW D,92(8),1.
MLA	Yu, Yu,et al."Kriging interpolating cosmic velocity field".PHYSICAL REVIEW D 92.8(2015):1.