Imprints of an extended Chevallier-Polarski-Linder parametrization on the large scales. (arXiv:1902.07108v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Pan_S/0/1/0/all/0/1">Supriya Pan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_W/0/1/0/all/0/1">Weiqiang Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paliathanasis_A/0/1/0/all/0/1">Andronikos Paliathanasis</a>
In the present work we perform a systematic analysis of a new dark energy
parametrization and its various corrections at first and higher orders around
the presence epoch $z=0$, where the first order correction of this dark energy
parametrization is the well known Chevallier-Polarski-Linder model. We have
considered up to the third order corrections of this parametrization and
investigate the models at the level of background and perturbations. The models
have been constrained using the latest astronomical datasets from a series of
potential astronomical data, such as the cosmic microwave background
observations, baryon acoustic oscillations measurements, recent Pantheon sample
of the supernova type Ia and the Hubble parameter measurements. From the
analyses we found that all parametrization favor the quintessential character
of the dark energy equation of state where the phantom crossing is marginally
allowed (within 68% CL). Probably the interesting outcome of the present work
is that as long as we increase the higher order corrections, the parameter
$w_{a}$ quantifying the dynamical nature of the dark energy parametrization
becomes weak in magnitude and hence this eventually confers that the higher
order corrections of the general dark energy parametrization are not much
significant. Finally, we perform the Bayesian analysis using
texttt{MCEvidence} to quantify the statistical deviations of the
parametrizations compared to the standard $Lambda$CDM cosmology. The Bayesian
analysis reports that $Lambda $CDM is favored over all the DE
parametrizations.
In the present work we perform a systematic analysis of a new dark energy
parametrization and its various corrections at first and higher orders around
the presence epoch $z=0$, where the first order correction of this dark energy
parametrization is the well known Chevallier-Polarski-Linder model. We have
considered up to the third order corrections of this parametrization and
investigate the models at the level of background and perturbations. The models
have been constrained using the latest astronomical datasets from a series of
potential astronomical data, such as the cosmic microwave background
observations, baryon acoustic oscillations measurements, recent Pantheon sample
of the supernova type Ia and the Hubble parameter measurements. From the
analyses we found that all parametrization favor the quintessential character
of the dark energy equation of state where the phantom crossing is marginally
allowed (within 68% CL). Probably the interesting outcome of the present work
is that as long as we increase the higher order corrections, the parameter
$w_{a}$ quantifying the dynamical nature of the dark energy parametrization
becomes weak in magnitude and hence this eventually confers that the higher
order corrections of the general dark energy parametrization are not much
significant. Finally, we perform the Bayesian analysis using
texttt{MCEvidence} to quantify the statistical deviations of the
parametrizations compared to the standard $Lambda$CDM cosmology. The Bayesian
analysis reports that $Lambda $CDM is favored over all the DE
parametrizations.
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