Validation of semi-analytical, semi-empirical covariance matrices for two-point correlation function for Early DESI data
Abstract
We present an extended validation of semi-analytical, semi-empirical covariance matrices for the two-point correlation function (2PCF) on simulated catalogs representative of Luminous Red Galaxies (LRG) data collected during the initial two months of operations of the Stage-IV ground-based Dark Energy Spectroscopic Instrument (DESI). We run the pipeline on multiple effective Zel'dovich (EZ) mock galaxy catalogs with the corresponding cuts applied and compare the results with the mock sample covariance to assess the accuracy and its fluctuations. We propose an extension of the previously developed formalism for catalogs processed with standard reconstruction algorithms. We consider methods for comparing covariance matrices in detail, highlighting their interpretation and statistical properties caused by sample variance, in particular, nontrivial expectation values of certain metrics even when the external covariance estimate is perfect. With improved mocks and validation techniques, we confirm a good agreement between our predictions and sample covariance. This allows one to generate covariance matrices for comparable datasets without the need to create numerous mock galaxy catalogs with matching clustering, only requiring 2PCF measurements from the data itself. The code used in this paper is publicly available at https://github.com/oliverphilcox/RascalC.
Keywords
Cite
@article{arxiv.2306.06320,
title = {Validation of semi-analytical, semi-empirical covariance matrices for two-point correlation function for Early DESI data},
author = {Michael Rashkovetskyi and Daniel J. Eisenstein and Jessica Nicole Aguilar and David Brooks and Todd Claybaugh and Shaun Cole and Kyle Dawson and Axel de la Macorra and Peter Doel and Kevin Fanning and Andreu Font-Ribera and Jaime E. Forero-Romero and Satya Gontcho A Gontcho and ChangHoon Hahn and Klaus Honscheid and Robert Kehoe and Theodore Kisner and Martin Landriau and Michael Levi and Marc Manera and Ramon Miquel and Jeongin Moon and Seshadri Nadathur and Jundan Nie and Claire Poppett and Ashley J. Ross and Graziano Rossi and Eusebio Sanchez and Christoph Saulder and Michael Schubnell and Hee-Jong Seo and Gregory Tarle and David Valcin and Benjamin Alan Weaver and Cheng Zhao and Zhimin Zhou and Hu Zou},
journal= {arXiv preprint arXiv:2306.06320},
year = {2023}
}
Comments
19 pages, 1 figure. Published in MNRAS. Code available at https://github.com/oliverphilcox/RascalC, table and figure data available at https://dx.doi.org/10.5281/zenodo.7750637