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SUMMARY:CMB temperature anisotropy at large scales induced by a causal pri
 mordial magnetic field - Camille Bonvin\, DAMTP
DTSTART:20110225T130000Z
DTEND:20110225T140000Z
UID:TALK28524@talks.cam.ac.uk
CONTACT:David Kubiznak
DESCRIPTION:Magnetic fields are ubiquitous in the Universe: they have been
  observed in galaxies\, in clusters of galaxies and also in the inter-clus
 ter medium. However\, the origin of these fields is still unclear. One pos
 sibility to explain the initial seed magnetic fields is that they originat
 ed in the primordial universe. A stochastic background of primordial magne
 tic fields generated before recombination can leave imprints on the temper
 ature anisotropy of the cosmic microwave background. In this talk I will p
 resent an analytical derivation of the CMB temperature anisotropy induced 
 at large scales from a primordial magnetic field. I will discuss the contr
 adictory results presented in the literature regarding this effect. I will
  show that the leading order term in the CMB spectrum is strongly suppress
 ed due to the presence of free-streaming neutrinos and that consequently t
 he magnetic Sachs Wolfe spectrum from a causal magnetic field behaves as l
 (l+1)Cl~l^2.
LOCATION:Pavilion B Potter Room (B1.19)
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