VETTOLANI G.

bservations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the equations of cosmic expansion, accounting for about 75 per cent of the total energy density in the Universe. The...

Measurements of the growth rate of structure f at different redshifts can discriminate the origin of cosmic acceleration. Coupled to estimates of the expansion rate H(z) as provided by Type-la supernovae or Baryonic Acoustic Oscillations, accurate measurements of f(z) are able to distinguish "dark energy" models from theories with modified...