Indicator Power Spectra: Surgical Excision of Non-linearities and Covariance Matrices for Counts in Cells [CEA]

http://arxiv.org/abs/2108.01673


We here introduce indicator functions, which identify regions of a given density in order to characterize the density dependence of clustering. After a general introduction to this tool, we show that indicator-function power spectra are biased versions of the linear spectrum on large scales. We provide a calculation from first principles for this bias, we show that it reproduces simulation results, and we provide a simple functional form for the translinear portion of the indicator-function spectra. We also outline two applications: first, these spectra facilitate surgical excision of non-linearity and thus significantly increase the reach of linear theory. Second, indicator-function spectra permit calculation of theoretical covariance matrices for counts-in-cells, facilitating parameter estimation with complementary CIC methods.

Read this paper on arXiv…

A. Repp and I. Szapudi
Thu, 5 Aug 21
39/57

Comments: 10 pages, 5 figures