Redshift evolution and covariances for joint lensing and clustering studies with DESI Y1
Abstract
Galaxy-galaxy lensing (GGL) and clustering measurements from the Dark Energy Spectroscopic Instrument Year 1 (DESI Y1) dataset promise to yield unprecedented combined-probe tests of cosmology and the galaxy-halo connection. In such analyses, it is essential to identify and characterise all relevant statistical and systematic errors. In this paper, we forecast the covariances of DESI Y1 GGL+clustering measurements and characterise the systematic bias due to redshift evolution in the lens samples. Focusing on the projected clustering and galaxy-galaxy lensing correlations, we compute a Gaussian analytical covariance, using a suite of N-body and log-normal simulations to characterise the effect of the survey footprint. Using the DESI One Percent Survey data, we measure the evolution of galaxy bias parameters for the DESI Luminous Red Galaxy (LRG) and Bright Galaxy Survey (BGS) samples. We find mild evolution in the LRGs in 0.4 < z < 0.8, subdominant compared to the expected statistical errors. For BGS, we find less evolution effects for brighter absolute magnitude cuts, at the cost of reduced sample size. We find that with a fiducial redshift bin width delta z = 0.1, evolution effects on GGL is negligible across all scales, all fiducial selection cuts, all fiducial redshift bins, given DESI Y1 sample size. Galaxy clustering is more sensitive to evolution due to the bias squared scaling. Nevertheless the redshift evolution effect is insignificant for clustering above the 1-halo scale of 0.1Mpc/h. For studies that wish to reliably access smaller scales, additional treatment of redshift evolution is likely needed. This study serves as a reference for GGL and clustering studies using the DESI Y1 sample
Keywords
Cite
@article{arxiv.2403.00915,
title = {Redshift evolution and covariances for joint lensing and clustering studies with DESI Y1},
author = {Sihan Yuan and Chris Blake and Alex Krolewski and Johannes Lange and Jack Elvin-Poole and Alexie Leauthaud and Joseph DeRose and Jessica Nicole Aguilar and Steven Ahlen and Gillian Beltz-Mohrmann and David Brooks and Todd Claybaugh and Axel de la Macorra and Peter Doel and Ni Putu Audita Placida Emas and Simone Ferraro and Jaime E. Forero-Romero and Cristhian Garcia-Quintero and Enrique Gaztañaga and Satya Gontcho A Gontcho and Boryana Hadzhiyska and Sven Heydenreich and Klaus Honscheid and Mustapha Ishak and Shahab Joudaki and Eric Jullo and Theodore Kisner and Anthony Kremin and Andrew Lambert and Martin Landriau and Marc Manera and Aaron Meisner and Ramon Miquel and Jundan Nie and Nathalie Palanque-Delabrouille and Claire Poppett and Anna Porredon and Mehdi Rezaie and Ashley J. Ross and Graziano Rossi and Rossana Ruggeri and Eusebio Sanchez and Christoph Saulder and Hee-Jong Seo and Joseph Harry Silber and Gregory Tarlé and Mariana Vargas-Magaña and Benjamin Alan Weaver and Enia Xhakaj and Zhimin Zhou and Hu Zou},
journal= {arXiv preprint arXiv:2403.00915},
year = {2024}
}
Comments
19 pages, 15 figures, submitted to MNRAS