Measurements of the Angular Homogeneity Scale from DESI DR1

Mariana Lopes-Dias; Carlos A. P. Bengaly; Xiaoyun Shao; Rodrigo Gonçalves; Paula S. Ferreira; Gabriela Coutinho de Carvalho; Jailson Alcaniz

arXiv · 2606.07854

Measurements of the Angular Homogeneity Scale from DESI DR1

Mariana Lopes-Dias·Carlos A. P. Bengaly·Xiaoyun Shao·Rodrigo Gonçalves·Paula S. Ferreira·Gabriela Coutinho de Carvalho·Jailson Alcaniz

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Abstract

The study of the large-scale distribution of galaxies provides essential information for testing the standard cosmological model, namely the $Λ$CDM paradigm. This scenario is based upon two foundations: General Relativity as the theory of gravity, and the Cosmological Principle, which states that the Universe is statistically homogeneous and isotropic on large scales -- so that we can measure distances and ages in the Universe assuming the FLRW metric. In this work, we perform a test of the Cosmological Principle by probing the angular homogeneity scale, $θ_H$, using the state-of-the-art observational data of Luminous Red Galaxies (LRGs) from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1). Our analysis is performed exclusively in two dimensions, across narrow redshift ranges inside a larger redshift sample of $0.4 < z < 1.1$, in two different surveyed regions of the sky (North and South Galactic Caps), as we want to minimize a priori dependences on an underlying cosmological model. We obtain that such a scale is indeed identified in all redshift ranges, and that they are consistent with mock simulations assuming the $Λ$CDM model. Moreover, our results are in great agreement with previous measurements using Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey Data Release 16 (SDSS-IV eBOSS DR16), as well as between the north and south galactic caps of the DESI DR1 survey. These findings help underpinning statistical isotropy and homogeneity of the Universe as a physically valid hypothesis in light of upcoming stage-IV redshift surveys, hence are consistent with one of the fundamental pillars of the standard cosmological model.

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Mariana Lopes-Dias, Carlos A. P. Bengaly, Xiaoyun Shao, Rodrigo Gonçalves, Paula S. Ferreira, Gabriela Coutinho de Carvalho, Jailson Alcaniz. 2026-06-05. Measurements of the Angular Homogeneity Scale from DESI DR1. https://arxiv.org/abs/2606.07854

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