A novel early Dark Energy model
  We present a theoretical study of an early dark energy (EDE) model. The
equation of state $\omega(z)$ evolves during the thermal history in a framework
of a Friedmann-Lemaitre-Robertson-Walker Universe, following an effective
parametrization that is a function of redshift $z$. We explore the evolution of
the system from the radiation domination era to the late times, allowing the
EDE model to have a non-negligible contribution at high redshift (as opposed to
the cosmological constant that only plays a role once the structure is formed)
with a very little input to the Big Bang Nucleosynthesis, and to do so, the
equation of state mimics the radiation behaviour, but being subdominant in
terms of its energy density. At late times, the equation of state of the dark
energy model asymptotically tends to the fiducial value of the De Sitter
domination epoch, providing an explanation for the accelerated expansion of the
Universe at late times, emulating the effect of the cosmological constant. The
proposed model has three free parameters, that we constrain using SNIa
luminosity distances, along with the CMB shift parameter and the deceleration
parameter calculated at the time of dark energy - matter equality. With full
knowledge of the best fit for our model, we calculate different observables and
compare these predictions with the standard$\Lambda$CDM model. Besides the
general consent of the community with the cosmological constant, there is no
fundamental reason to choose that particular candidate as dark energy. Here, we
open the opportunity to consider a more dynamical model, that also accounts for
the late accelerated expansion of the Universe.
