Impact of Large-Scale Anisotropies on Galaxy Clustering and Cosmological Constraints

TL;DR

This paper examines how large-scale anisotropies, like dipoles, affect galaxy clustering measurements and emphasizes the importance of addressing these systematics for accurate cosmological constraints in future surveys.

Contribution

It provides a critical assessment of the impact of large-scale anisotropies on galaxy clustering signals and offers guidelines for mitigating their effects in cosmological analyses.

Findings

Large-scale anisotropies significantly influence 2PCF and $C_$.

Addressing systematics and masking anisotropies improves cosmological parameter estimation.

Anisotropies can mimic non-Gaussianity signals, affecting interpretations.

Abstract

We critically assess the impact of significant dipole and large-scale anisotropies on galaxy clustering signals, with a focus on radio continuum surveys. Our study reveals that these anisotropies -- resulting from intrinsic cosmological effects and/or observational systematics -- profoundly influence the two-point correlation function (2PCF) and angular power spectrum ($C_\ell$). Notably, large-scale anisotropies can obscure or simulate non-Gaussianity signals, complicating the extraction of precise cosmological information. The results emphasize that it is crucial to address systematics and rigorously mask the dipole and its surrounding multipoles to obtain accurate cosmological constraints. This approach is essential for extracting cosmological results from clustering signals, particularly for future surveys such as SKA, DESI, and LSST, to ensure the precision and reliability of cosmological analyses.