Jun 17 (Wed), 14:15 in A315 (Cosmo Seminar)  

Francesc Ferrer (Washington University, St. Louis)

Searching for cosmological magnetic fields in the diffuse gamma-ray background

Several CP violating processes occurring in the early universe could have produced weak-field helical magnetic seed fields that would have subsequently grown, amplified via different types of dynamo mechanism, accounting for the presently observed astronomical-sized fields. The structure of these large-scale magnetic fields is imprinted on the gamma-ray sky through secondary cascades. Using data from the Fermi satellite we evaluate a CP odd statistic and find it to be non-zero above the $2 \sigma$ level. This results indicate a left-handed helical magnetic field of $10^{-14}G$ on $~10$ Mpc scales.