A divergence-free parametrization for dynamical dark energy

Abstract

We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor $a$ and in redshift $z$, which diverges neither in the past nor future and contains the same number of degrees of freedom with the former two. We present constraints of the cosmological parameters using the most updated baryon acoustic oscillation (BAO) measurements along with cosmic microwave background (CMB) data and a recent reanalysis of Type Ia supernova (SN) data. This new parametrization allowed us to carry out successive observational analyses by decreasing its degrees of freedom systematically until ending up with a dynamical dark energy model that has the same number of parameters with $\Lambda$CDM. We found that the dark energy source with a dynamical equation of state parameter equal $-2/3$ at the early universe and $-1$ today fits the data slightly better than $\Lambda$.

9 pages, 3 tables, 10 figures; matches the version published in JCAP

References in corpus (8)

• Dynamics of dark energy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• WMAP constraints on low redshift evolution of dark energy
• A parametric model for dark energy
• Reconstruction of the Dark Energy equation of state
• Two Component Model of Dark Energy
• Late Time Acceleration of the 3-Space in a Higher Dimensional Steady State Universe in Dilaton Gravity

Cited by in corpus (1)

• Cosmology In Terms Of The Deceleration Parameter. Part II