Optimization of spectroscopic surveys for testing non-Gaussianity

TL;DR

This paper explores how to optimize future spectroscopic surveys to improve measurements of primordial non-Gaussianity, focusing on survey design and the potential for constraints comparable to current CMB limits.

Contribution

It provides a detailed analysis of survey parameter trade-offs and defines observational requirements to detect f_NL of order 1, highlighting the need for higher-order statistics.

Findings

Power spectrum constraints can be competitive with current CMB limits.

Higher-order statistics are necessary for sub-unity precision in f_NL.

Survey design trade-offs impact the ability to measure non-Gaussianity.

Abstract

We investigate optimization strategies to measure primordial non-Gaussianity with future spectroscopic surveys. We forecast measurements coming from the 3D galaxy power spectrum and compute constraints on primordial non-Gaussianity parameters f_NL and n_NG. After studying the dependence on those parameters upon survey specifications such as redshift range, area, number density, we assume a reference mock survey and investigate the trade-off between number density and area surveyed. We then define the observational requirements to reach the detection of f_NL of order 1. Our results show that while power spectrum constraints on non-Gaussianity from future spectroscopic surveys can be competitive with current CMB limits, measurements from higher-order statistics will be needed to reach a sub unity precision in the measurements of the non-Gaussianity parameter f_NL.