We investigate the relationship between the mass and velocity fields of the intergalactic medium (IGM) and dark matter. Although the evolution of the IGM is dynamically governed by the gravity of the underlying dark matter field, some statistical properties of the IGM inevitably decouple from those of the dark matter once the nonlinearity of the dynamical equations and the stochastic nature of ...

Following recent results from the Super-Kamiokande experiment which indicate that neutrinos may have finite masses and provide at least part of the dark matter in the Universe, we reexamine the decaying neutrino hypothesis of Sciama, including for the first time the effects of absorption by intergalactic dust. We consider several dust models, including one designed to optimize ultraviolet extin...

A variety of approximate schemes for modelling the low-density Intergalactic Medium (IGM) in the high-redshift Universe is compared to the results of a large high-resolution hydro-dynamical simulation. These schemes use either an analytical description of the dark matter distribution and the IGM or numerical simulations of the DM distributions combined with different approximate relations betwe...

We study the anisotropy of the cosmic microwave background (CMB) in cold and mixed dark matter (CDM and MDM) models, with non scale-invariant primordial power spectra (i.e. n 6= 1) and a late, sudden reionization of the intergalactic medium at redshift zrh. We test these models against recent detections of CMB anisotropy at large and intermediate angular scales. We find that current CMB anisotr...