Recent surveys seem to support bulk peculiar velocities well in excess of those anticipated
by the standard cosmological model. In view of these results, we consider here some of the
theoretical implications of large-scale drift motions. We find that observers with small, but …

It is widely believed that primordial magnetic fields are dramatically diluted by the expansion
of the Universe. As a result, cosmological magnetic fields with residual strengths of
astrophysical relevance are generally sought by going outside standard cosmology or by …

We use covariant techniques to study the non-linear evolution of self-gravitating, non-
relativistic media. The formalism is first applied to imperfect fluids, aiming at the kinematic
effects of viscosity, before extended to inhomogeneous magnetized environments. The non …

Recent surveys indicate coherent large-scale peculiar motions, commonly referred to as
'dark flows', considerably stronger than expected. At the same time, an increasing number of
reports suggest the presence of a weak dipolar anisotropy in the supernova data. The …

We study inhomogeneous magnetized cosmologies through the post-recombination era in
the framework of Newtonian gravity and the ideal-magnetohydrodynamic limit. The non-
linear kinematic and dynamic equations are derived and linearized around the Newtonian …

We consider the 'kinematics' of space-like congruences and apply them to a family of self-
gravitating magnetic forcelines. Our aim is to investigate the convergence and the possible
focusing of these lines, as well as their rotation and shear deformation. In so doing, we …

We generalize the relativistic expression of Ohm's law by studying a multifluid system of
charged species using the 1+ 3 covariant formulation of general relativistic electrodynamics.
This is done by providing a fully relativistic, fully non-linear propagation equation for the …

We study the linear magnetohydrodynamic behavior of a Newtonian cosmology with a
viscous magnetized fluid of finite conductivity and generalize the Jeans instability criterion.
The presence of the field favors the anisotropic collapse of the fluid, which in turn leads to …

The temperature anisotropies and polarization of the cosmic microwave background (CMB)
radiation provide a window back to the physics of the early universe. They encode the
nature of the initial fluctuations and so can reveal much about the physical mechanism that …