Analytic Gaussian covariance matrices for galaxy N -point correlation functions
Abstract
We derive analytic covariance matrices for the N -point correlation functions (NPCFs) of galaxies in the Gaussian limit. Our results are given for arbitrary N and projected onto the isotropic basis functions given by spherical harmonics and Wigner 3 j symbols. A numerical implementation of the 4PCF covariance is compared to the sample covariance obtained from a set of lognormal simulations, Quijote dark matter halo catalogues, and MultiDark-Patchy galaxy mocks, with the latter including realistic survey geometry. The analytic formalism gives reasonable predictions for the covariances estimated from mock simulations with a periodic-box geometry. Furthermore, fitting for an effective volume and number density by maximizing a likelihood based on Kullback-Leibler divergence is shown to partially compensate for the effects of a nonuniform window function. Our result is recently shown to facilitate NPCF analysis on a realistic survey data.
- Publication:
-
Physical Review D
- Pub Date:
- August 2022
- DOI:
- 10.1103/PhysRevD.106.043515
- arXiv:
- arXiv:2108.01714
- Bibcode:
- 2022PhRvD.106d3515H
- Keywords:
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- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 31 pages, 17 figures