On the degeneracy between primordial tensor modes and cosmic strings in future CMB data from Planck

TL;DR

This paper examines whether future CMB data from Planck can differentiate between primordial tensor modes and cosmic strings, concluding that there is no significant degeneracy between these sources of B-mode polarization.

Contribution

The study analyzes the potential confusion between primordial tensors and cosmic strings in CMB data, demonstrating that Planck can effectively distinguish between them.

Findings

No significant degeneracy between tensors and cosmic strings in Planck data

Planck can reliably identify the origin of B-mode polarization

Cosmic strings and primordial tensors produce distinguishable signatures

Abstract

While observations indicate that the predominant source of cosmic inhomogeneities are adiabatic perturbations, there are a variety of candidates to provide auxiliary trace effects, including inflation-generated primordial tensors and cosmic defects which both produce B-mode cosmic microwave background (CMB) polarization. We investigate whether future experiments may suffer confusion as to the true origin of such effects, focusing on the ability of Planck to distinguish tensors from cosmic strings, and show that there is no significant degeneracy.