Baryon Acoustic Oscillations in the Lyman Alpha Forest

TL;DR

This study uses large-scale hydrodynamic simulations to investigate the potential for detecting baryon acoustic oscillations in the Lyman alpha forest, demonstrating a moderate statistical detection at redshift 3.

Contribution

The paper presents high-resolution simulations incorporating BAO features to assess their observability in the Lyman alpha forest, addressing numerical challenges due to scale differences.

Findings

BAO signal detected at z=3 with moderate significance

Simulations successfully model Lyman alpha forest with BAO features

Cross-correlation function reveals BAO imprint in synthetic spectra

Abstract

We use hydrodynamic cosmological simulations in a (600 Mpc)^3 volume to study the observability of baryon acoustic oscillations (BAO) in the intergalactic medium as probed by Lyman alpha forest (LAF) absorption. The large scale separation between the wavelength of the BAO mode (~150 Mpc) and the size of LAF absorbers (~100 kpc) makes this a numerically challenging problem. We report on several 2048^3 simulations of the LAF using the ENZO code. We adopt WMAP5 concordance cosmological parameters and power spectrum including BAO perturbations. 5000 synthetic HI absorption line spectra are generated randomly piercing the box face. We calculate the cross-correlation function between widely separated pairs. We detect the BAO signal at z=3 where theory predicts to moderate statistical significance.