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

Moss, Adam; Pogosian, Levon


Associate Professor

Levon Pogosian


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.


Moss, A., & Pogosian, L. (2014). Did BICEP2 See Vector Modes? First B-Mode Constraints on Cosmic Defects. Physical Review Letters, 112(17),

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
Public URL
Publisher URL
PMID 00033864
Additional Information © 2014 American Physical Society