Joanes Lizarraga

Can topological defects mimic the BICEP2 B-mode signal?

We show that the B-mode polarization signal detected at low multipoles by BICEP2 cannot be entirely due to topological defects. This would be incompatible with the high-multipole B-mode polarization data and also with existing temperature anisotropy data. Adding cosmic strings to a model with tensors, we find that B modes on their own provide a comparable limit on the defects to that already coming from Planck satellite temperature data. We note that strings at this limit give a modest improvement to the best fit of the B-mode data, at a somewhat lower tensor-to-scalar ratio of r ≃ 0.15.

Constraining topological defects with temperature and polarization anisotropies

We analyse the possible contribution of topological defects to cosmic microwave anisotropies, both temperature and polarisation. We allow for the presence of both inflationary scalars and tensors, and of polarised dust foregrounds that may contribute to or dominate the B-mode polarisation signal. We confirm and quantify our previous statements that topological defects on their own are a poor fit to the B-mode signal. However, adding topological defects to a models with a tensor component or a dust component improves the fit around

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

\ell=200

New CMB constraints for Abelian Higgs cosmic strings

. Fitting simultaneously to both temperature and polarisation data, we find that textures fit almost as well as tensors (

Energy-momentum correlations for Abelian Higgs cosmic strings

\Delta\chi^2 = 2.0

Correlations between cosmic strings and extra relativistic species

), while Abelian Higgs strings are ruled out as the sole source of the B-mode signal at low

Cosmic Microwave Background constraints for global strings and global monopoles

\ell

Survival of

. The 95% confidence upper limits on models combining defects and dust are

pq

G\mu < 2.7\times 10^{-7}

-superstrings in field theory simulations

(Abelian Higgs strings),