On the equivalence between galaxy angular correlation function and power spectrum in constraining primordial non-Gaussianity

2025/01/22 by Ryo Terasawa, Terasawa, Ryo, Yue Nan +3 · 1 citation
Mathematics · Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Statistical and numerical algorithms

paper · pdf · doi:10.48550/arxiv.2501.12661

openalex publication_date 2025/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We investigate the angular power spectrum (C_ℓ) and angular correlation function (w(θ)) of galaxy number density field in the presence of the local-type primordial non-Gaussianity (PNG), explicitly accounting for the integral constraint in an all-sky survey. We show that the PNG signature in C_ℓ is confined to low multipoles in the linear regime, whereas its signature in w(θ) extends across a wide range of angular scales, including those below the nonlinear scale. Therefore, the equivalence between C_ℓ and w(θ) can be violated when scale cuts of multipoles or angular scales -- for example, to mitigate systematic effects -- are applied in the analysis. Assuming samples of photometric galaxies divided into multiple redshift bins in the range 0

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