Seshadri, T. R. ; Subramanian, Kandaswamy (2009) Cosmic microwave background bispectrum from primordial magnetic fields on large angular scales Physical Review Letters, 103 (8). 081303. ISSN 0031-9007
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Official URL: http://prl.aps.org/abstract/PRL/v103/i8/e081303
Related URL: http://dx.doi.org/10.1103/PhysRevLett.103.081303
Abstract
Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In contrast, CMB non-Gaussianity due to inflationary scalar perturbations arises only as a higher-order effect. We propose a novel probe of stochastic primordial magnetic fields that exploits the characteristic CMB non-Gaussianity that they induce. We compute the CMB bispectrum (bl1l2l3) induced by such fields on large angular scales. We find a typical value of l1(l1+1)l3(l3+1)bl1l2l3∼10-22, for magnetic fields of strength B0˜3 nG and with a nearly scale invariant magnetic spectrum. Observational limits on the bispectrum allow us to set upper limits on B0∼35 nG.
Item Type: | Article |
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Source: | Copyright of this article belongs to The American Physical Society. |
ID Code: | 68043 |
Deposited On: | 02 Nov 2011 03:16 |
Last Modified: | 02 Nov 2011 03:16 |
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