Lensing smoothing of BAO wiggles

TL;DR

This paper non-perturbatively analyzes how gravitational lensing deflections smooth out BAO wiggles in the matter power spectrum, revealing a significant, survey-independent effect that becomes prominent at higher redshifts.

Contribution

It introduces a non-perturbative study of lensing effects on BAO wiggles, highlighting a geometrical smoothing effect not previously incorporated in BAO analyses.

Findings

Lensing causes about 1% dispersion at BAO scale from redshift z~2.

The effect smears out BAO wiggles, reducing power spectrum amplitude by 0.1-0.2%.

Lensing effects become comparable to non-linear structure formation at z~4.

Abstract

We study non-perturbatively the effect of the deflection angle on the BAO wiggles of the matter power spectrum in real space. We show that from redshift z~2 this introduces a dispersion of roughly 1 Mpc at BAO scale, which corresponds approximately to a 1% effect. The lensing effect induced by the deflection angle, which is completely geometrical and survey independent, smears out the BAO wiggles. The effect on the power spectrum amplitude at BAO scale is about 0.1% for z~2 and 0.2% for z~4. We compare the smoothing effects induced by the lensing potential and non-linear structure formation, showing that the two effects become comparable at z~4, while the lensing effect dominates for sources at higher redshifts. We note that this effect is not accounted through BAO reconstruction techniques.