Imprint of a Steep Equation of State in the growth of structure

Understand

We study the cosmological properties of a dynamical of dark energy (DE) component determined by a Steep Equation of State (SEoS) $w(z)=w_0+w_i\frac{(z/z_T)^q}{1+(z/z_T)^q}$.

• The SEoS has a transition at $z_T$ between two pivotal values ($w_i, w_0$) which can be taken as an early time and present day values of $w$ and the steepness is given by $q$.
• We describe the impact of this dynamical DE at background and perturbative level.
• The steepness of the transition has a better cosmological fit than a conventional CPL model with $w=w_0+w_a(1-a)$.