Cosmological Features of Primordial Magnetic Fields
  The aim of this thesis is to study the effects on the CMB anisotropy due to
primordial magnetic fields and to analyze some favorable scenarios of
magnetogenesis constrained by those signatures, including limits on the
amplitude of the fields from bounds on CMB non-Gaussianity and background
models. In fact, we found out that helicity in the fields plays an important
role in the analysis PMFs origin, by generating significant features in the
cross-correlation polarization pattern and the increasing of the signal in the
reduced CMB bispectrum. In the latter case, we reported that non-causal fields
(mainly generated during the inflation epoch) are the most favorable models
constrained by CMB observations. Moreover, we have studied the presence of an
IR cutoff in the spectra and bispectra finding appealing unique features from
primordial magnetic fields. Another important result shown in this thesis is
the equivalence between different approaches of cosmological perturbation
theory in the magnetized context. In fact, assuming a magnetized Universe and
building gauge invariant quantities in both approaches: the 1+3covariant and
the gauge invariant; we found out that those invariants represent the same
physical meaning. Besides, we define gauge invariant related to the
electromagnetic potentials which in future works, could help us to study
magnetogenesis models on perturbed scenarios.
