Detection of relic gravitational waves in the CMB: Prospects for CMBPol mission

TL;DR

This paper evaluates the potential of the CMBPol mission to detect relic gravitational waves through their imprint on the CMB, focusing on constraining key parameters despite contamination challenges.

Contribution

It provides a detailed analysis of how CMBPol can jointly constrain the tensor-to-scalar ratio and spectral index, considering contamination effects.

Findings

CMBPol can detect relic gravitational waves if r ≥ 0.001

Joint constraints on r and n_t are feasible with CMBPol data

Contamination effects significantly influence detection prospects

Abstract

Detection of relic gravitational waves, through their imprint in the cosmic microwave background radiation, is one of the most important tasks for the planned CMBPol mission. In the simplest viable theoretical models the gravitational wave background is characterized by two parameters, the tensor-to-scalar ratio $r$ and the tensor spectral index $n_t$. In this paper, we analyze the potential joint constraints on these two parameters, $r$ and $n_t$, using the potential observations of the CMBPol mission, which is expected to detect the relic gravitational waves if $r\gtrsim0.001$. The influence of the contaminations, including cosmic weak lensing, various foreground emissions, and systematical errors, is discussed.