The local B-polarization of the CMB: a very sensitive probe of cosmic defects - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




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Abstract: We present a new and especially powerful signature of cosmic strings andother topological or non-topological defects in the polarization of the cosmicmicrowave background CMB. We show that even if defects contribute 1% or lessin the CMB temperature anisotropy spectrum, their signature in the local$\tilde{B}$-polarization correlation function at angular scales of tens of arcminutes is much larger than that due to gravitational waves from inflation,even if the latter contribute with a ratio as big as $r\simeq 0.1$ to thetemperature anisotropies. We show that when going from non-local to local$\tilde{B}$-polarization, the ratio of the defect signal-to-noise with respectto the inflationary value increases by about an order of magnitude. ProposedB-polarization experiments, with a good sensitivity on arcminute scales, mayeither detect a contribution from topological defects produced after inflationor place stringent limits on them. Even Planck should be able to improvepresent constraints on defect models by at least an order of magnitude, to thelevel of $\ep <10^{-7}$. A future full-sky experiment like CMBpol, withpolarization sensitivities of the order of $1\mu$K-arcmin, will be able toconstrain the defect parameter $\ep=Gv^2$ to a few $\times10^{-9}$, dependingon the defect model.



Author: Juan Garcia-Bellido, Ruth Durrer, Elisa Fenu, Daniel G. Figueroa, Martin Kunz

Source: https://arxiv.org/







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