In this talk I will discuss the decay of gravitational waves into dark energy fluctuations, made possible by the spontaneous breaking of Lorentz invariance due to dark energy. For some operators of the EFT of Dark Energy (or Horndeski/beyond Horndeski theories) this decay process is large. Hence, recent observations rule out such couplings. This constraint, together with the requirement that...
Using hyperconical universes with linear expansion, radially inhomogeneous metrics can be obtained by local time-preserved transformations. This model tends to a locally flat Friedman-Robertson-Walker metric with linear expansion. The corresponding luminosity distance was obtained and compared with the observations of 580 SNe Ia, taken from the Supernova Cosmology Project (SCP). The best fit...
The evolution of cosmological perturbations, at large scales, is primarily determined by the gravitational clustering of cold dark matter, which has traditionally been modelled as a presureless perfect fluid. At small scales and at late times however, orbit crossing leads to a nonzero velocity dispersion and vorticity in the dark matter distribution, and while several studies of orbit crossing...
We introduce a new test to study the cosmological principle with galaxy clusters. Galaxy clusters exhibit a tight correlation between the luminosity and temperature of the X-ray-emitting intracluster medium. While the luminosity measurement depends on cosmological parameters through the luminosity distance, the temperature determination is cosmology-independent. We exploit this property to...
