Phenomenology of BAO evolution from Lagrangian to Eulerian Space

TL;DR

This paper investigates the evolution of the BAO feature from Lagrangian to Eulerian space using simulations, revealing a sharper initial BAO in halos and analyzing the effects of bias and reconstruction on BAO contrast.

Contribution

It demonstrates that the initial BAO in halos is sharper than in linear matter and explores how bias and reconstruction influence BAO evolution.

Findings

Initial BAO in halos is significantly sharper than in linear matter.

Higher-derivative and velocity bias affect the BAO scale-dependence.

Reconstruction impacts the contrast of BAO related to velocity and gravity bias.

Abstract

The baryon acoustic oscillation (BAO) feature provides an important distance scale for the measurement of the expansion history of the Universe. Theoretical models of the BAO in the distribution of biased tracers of the large scale structure usually rely on an initially linear BAO. With aid of N-body simulations, we demonstrate that the BAO in the initial (Lagrangian) halo 2-point function is significantly sharper than in the linear matter distribution, in agreement with peak theory. Using this approach, we delineate the scale-dependence induced by the higher-derivative and velocity bias before assessing how much of the initial BAO enhancement survives until the collapse epoch. Finally, we discuss the extent to which the velocity or gravity bias, which is also imprinted in the displacement field of halos, affects the contrast of the BAO obtained with a reconstruction.