Baryon Acoustic Oscillations analyses with Density-Split Statistics

TL;DR

This paper investigates how the non-linear evolution of Baryon Acoustic Oscillations varies across different cosmic environments using density-split statistics, revealing environment-dependent shifts and broadening effects that impact cosmological measurements.

Contribution

It introduces the use of density-split statistics to analyze environment-dependent non-linear effects on BAO, providing new insights beyond traditional two-point correlation functions.

Findings

Density-dependent shifts in BAO position are detected in simulations.

BAO broadening increases in high-density regions over time.

Low-density regions show stable, narrower BAO features.

Abstract

Accurate modeling for the evolution of the Baryon Acoustic Oscillations (BAO) is essential for using it as a standard ruler to probe cosmology. We explore the non-linearity of the BAO in different environments using the density-split statistics and compare them to the case of the conventional two-point correlation function (2PCF). We detect density-dependent shifts for the position of the BAO with respect to its linear version using halos from N-body simulations. Around low/high-densities, the scale of the BAO expands/contracts due to non-linear peculiar velocities. As the simulation evolves from redshift 1 to 0, the difference in the magnitude of the shifts between high- and low-dense regions increases from the sub-percent to the percent level. The width of the BAO around high density regions increases as the universe evolves, similar to the known broadening of the BAO in the 2PCF due to non-linear evolution. In contrast, the width is smaller and stable for low density regions. We discuss possible implications for the reconstructions of the BAO in light of our results.