Cosmological constraints of phantom dark energy models

Abstract

We address three genuine phantom dark energy models where each of them induces the particular future events known as Big Rip, Little Rip and Little Sibling of the Big Rip. The background models are fully determined by a given dark energy equation of state. We first observationally constrain the corresponding model parameters that characterise each paradigm using the available data of supernova type Ia, Cosmic Microwave Background and Baryonic Acoustic Oscillations by using a Markov Chain Monte Carlo method. The obtained fits are used to solve numerically the first order cosmological perturbations. We compute the evolution of the density contrast of (dark) matter and DE, from the radiation dominated era till a totally DE dominated universe. Then, the obtained results are compared with respect to $\Lambda$CDM. We obtain the predicted current matter power spectrum and the evolution of $f\sigma_8$ given by the models studied in this work. Finally, the models are tested by computing the reduced $\chi^2$ for the `Gold2017' $f\sigma_8$ dataset.