Acoustic signatures in the Cosmic Microwave Background bispectrum from primordial magnetic fields

  title={Acoustic signatures in the Cosmic Microwave Background bispectrum from primordial magnetic fields},
  author={Rong-gen Cai and Bin Hu and Hong-bo Zhang},
  journal={Journal of Cosmology and Astroparticle Physics},
Using the full radiation transfer function, we numerically calculate the CMB angular bispectrum seeded by the compensated magnetic scalar density mode. We find that, for the string inspired primordial magnetic fields characterized by index nB = −2.9 and mean-field amplitude Bλ = 9nG, the angular bispectrum is dominated by two primordial magnetic shapes. The first magnetic shape looks similar to the one from local-type primordial curvature perturbations, so both the amplitude and profile of the… 
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