Tracing The Sound Horizon Scale With Photometric Redshift Surveys

TL;DR

This paper introduces a simple empirical method to measure the baryon acoustic oscillation scale using photometric redshift galaxy surveys, improving robustness against systematic shifts.

Contribution

It presents a new, robust approach for extracting the sound horizon scale from photometric surveys by fitting the angular correlation function with a power law and Gaussian.

Findings

Method accurately estimates the BAO scale in mock DES data.

Systematic errors are mainly due to photo-z uncertainties.

Robust against projection bias and non-linear effects.

Abstract

We propose a new method for cosmological parameters extraction using the baryon acoustic oscillation scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical parametric fit to the angular 2-point correlation function w(theta). It is parametrized as a power law to describe the continuum plus a Gaussian to describe the BAO bump. The location of the Gaussian is used as the basis for the measurement of the sound horizon scale. This method, although simple, actually provides a robust estimation, since the inclusion of the power law and the use of the Gaussian removes the shifts which affect the local maximum. We discuss the effects of projection bias, non-linearities, redshift space distortions and photo-z precision, and apply our method to a mock catalog of the Dark Energy Survey, built upon a large N-body simulation provided by the MICE collaboration. We discuss the main systematic errors associated to our method and show that they are dominated by the photo-z uncertainty.