Did BICEP2 See Vector Modes? First B-Mode Constraints on Cosmic Defects

Moss, Adam; Pogosian, Levon

Abstract

Scaling networks of cosmic defects, such as strings and textures, actively generate scalar, vector, and tensor metric perturbations throughout the history of the Universe. In particular, vector modes sourced by defects are an efficient source of the cosmic microwave background B-mode polarization. We use the recently released BICEP2 and POLARBEAR B-mode polarization spectra to constrain properties of a wide range of different types of cosmic strings networks. We find that in order for strings to provide a satisfactory fit on their own, the effective interstring distance needs to be extremely large—spectra that fit the data best are more representative of global strings and textures. When a local string contribution is considered together with the inflationary B-mode spectrum, the fit is improved. We discuss implications of these results for theories that predict cosmic defects.

Citation

Moss, A., & Pogosian, L. (2014). Did BICEP2 See Vector Modes? First B-Mode Constraints on Cosmic Defects. Physical Review Letters, 112(17), Article 171302. https://doi.org/10.1103/PhysRevLett.112.171302

• Journal Article Type: Article
• Acceptance Date: Apr 10, 2014
• Online Publication Date: Apr 29, 2014
• Publication Date: May 2, 2014
• Deposit Date: Sep 21, 2017
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 112
• Issue: 17
• Article Number: 171302
• DOI: https://doi.org/10.1103/PhysRevLett.112.171302
• Public URL: https://nottingham-repository.worktribe.com/output/1114183
• Publisher URL: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.171302
• PMID: 00033864
• Additional Information: © 2014 American Physical Society