We consider the impact of a stochastic background of primordial magnetic fields with non-vanishing helicity on CMB anisotropies in temperature and polarization. We compute the exact expressions for the scalar, vector and tensor part of the energy-momentum tensor including the helical contribution, by assuming a power-law dependence for the spectra and a comoving cutoff which mimics the damping due to viscosity. We also compute the parity-odd correlator between the helical and non-helical contribution which generate the TB and EB cross-correlation in the CMB pattern. We finally show the impact of including the helical term on the power spectra of CMB anisotropies up to multipoles with ℓ ∼ (103).
CMB anisotropies generated by a stochastic background of primordial magnetic fields with non-zero helicity / Ballardini M.; Finelli F.; Paoletti D.. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - ELETTRONICO. - 2015:10(2015), pp. 031.031-031.031. [10.1088/1475-7516/2015/10/031]
CMB anisotropies generated by a stochastic background of primordial magnetic fields with non-zero helicity
Ballardini M.
Primo
;
2015
Abstract
We consider the impact of a stochastic background of primordial magnetic fields with non-vanishing helicity on CMB anisotropies in temperature and polarization. We compute the exact expressions for the scalar, vector and tensor part of the energy-momentum tensor including the helical contribution, by assuming a power-law dependence for the spectra and a comoving cutoff which mimics the damping due to viscosity. We also compute the parity-odd correlator between the helical and non-helical contribution which generate the TB and EB cross-correlation in the CMB pattern. We finally show the impact of including the helical term on the power spectra of CMB anisotropies up to multipoles with ℓ ∼ (103).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.