Towards an Optimal Reconstruction of Baryon Oscillations

TL;DR

This paper introduces an improved method for reconstructing baryon acoustic oscillations that enhances peak sharpness and accuracy by using a parameter-free, optimal filtering approach, leading to better cosmological measurements.

Contribution

The proposed reconstruction method removes free parameters and treats large-scale modes consistently, improving the sharpening of the BAO peak over standard techniques.

Findings

Marked improvement in peak sharpening at redshift zero

No free parameters needed in the new reconstruction scheme

Enhanced extraction of BAO information using optimal filters

Abstract

The Baryon Acoustic Oscillations (BAO) in the large-scale structure of the universe leave a distinct peak in the two-point correlation function of the matter distribution. That acoustic peak is smeared and shifted by bulk flows and non-linear evolution. However, it has been shown that it is still possible to sharpen the peak and remove its shift by undoing the effects of the bulk flows. We propose an improvement to the standard acoustic peak reconstruction. Contrary to the standard approach, the new scheme has no free parameters, treats the large-scale modes consistently, and uses optimal filters to extract the BAO information. At redshift of zero, the reconstructed linear matter power spectrum leads to a markedly improved sharpening of the reconstructed acoustic peak compared to standard reconstruction.