GI BAO as a cosmological consistency check

TL;DR

This paper introduces GI BAO as a new cosmological consistency check, demonstrating its application with DES Y3 data and highlighting its potential for future large-scale surveys.

Contribution

The paper presents the first measurement of GI BAO on photometric data and shows it can validate density BAO, shear measurements, and alignment models.

Findings

GI BAO measurement on DES Y3 data yields $\,0.966 \, ext{(1$\sigma$)}$, consistent with density BAO.

GI BAO can serve as a robust consistency check for cosmological measurements.

Combining density and GI BAO enhances resilience to systematic effects.

Abstract

Tensions often arise between different datasets in cosmology, and consistency tests can serve as a powerful tool for diagnosing potential issues. The density-shear Baryon Acoustic Oscillations (GI BAO) are the imprint of the BAO feature on the shear field induced by the large-scale tidal field. We highlight that GI BAO can provide a robust consistency check for the density BAO, shear measurement, and alignment model. Failure of this check hints at systematics in any of these parts. As an illustration, we present the first GI BAO measurement on photometric data, using the DES Y3 dataset. We find the GI BAO constraint on the BAO scale dilation parameter $\alpha $ to be $ 0.966 \pm 0.252 $ (1$\sigma$), in good agreement with the density BAO constraint, $ 0.966 \pm 0.037 $, thereby validating the density BAO, shear measurement, and the linear alignment model. Furthermore, we argue that combining the density BAO with the GI BAO yields results that are more resilient to systematic effects. Thanks to the massive data volumes of stage IV surveys, the GI BAO will play an even more prominent role as a consistency check.