Abstract: |
Currently, the Universe goes through an accelerated expansion, different observations have proved such fact: (SNeIa, BAO, CMB anisotropies, LSS formation, Weak Lensing). Even more, future projects and surveys are underway or being proposed to discover the underlying cause of this phenomena. The current cosmological paradigm, LCDM, models the dark energy (DE) component as a constant term that produces late time acceleration. However some degrees of tension have appeared among different data sets which has renewed the interest on alternative models that can provide an acceleration mechanism. Parametric approaches are a useful way to study alternative models for DE. In this talk I present two different parametric forms for the equation of state for DE. The first is motivated by scalar field dynamics such as in quintessence models and recovers the widely used CPL equation but allows for a richer behavior. The second parametrization can reproduce a f(R)-like evolution with sub percent precision over the numerical solutions. In both cases the constraints using observations are discussed. |