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The intrinsic B-mode polarisation of the cosmic mMicrowave background

journal contribution
posted on 2023-06-08, 17:56 authored by Guido Pettinari, Christian Fidler, Martin Beneke, Robert Crittenden, Kazuya Koyama, David Wands
We estimate the B-polarisation induced in the Cosmic Microwave Background by the non-linear evolution of density perturbations. Using the second-order Boltzmann code SONG, our analysis incorporates, for the first time, all physical effects at recombination. We also include novel contributions from the redshift part of the Boltzmann equation and from the bolometric definition of the temperature in the presence of polarisation. The remaining line-of-sight terms (lensing and time-delay) have previously been studied and must be calculated non-perturbatively. The intrinsic B-mode polarisation is present independent of the initial conditions and might contaminate the signal from primordial gravitational waves. We find this contamination to be comparable to a primordial tensor-to-scalar ratio of r?10-7 at the angular scale l?100, where the primordial signal peaks, and r?5·10-5 at l?700, where the intrinsic signal peaks. Therefore, we conclude that the intrinsic B-polarisation from second-order effects is not likely to contaminate future searches of primordial gravitational waves.

Funding

Astronomy rolling grant; G0278; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/I000976/1

History

Publication status

  • Published

File Version

  • Submitted version

Journal

Journal of Cosmology and Astroparticle Physics

ISSN

1475-7516

Publisher

IoP

Volume

2014

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • No

Peer reviewed?

  • No

Legacy Posted Date

2014-07-28

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