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Comparison of dark energy models after Planck 2015

Yue-Yao Xu, Xin Zhang

TL;DR

This study tackles the problem of identifying which dark energy models best explain the current expansion history by fitting ten representative models to a uniform data set that combines SN Ia from JLA, Planck 2015 distance priors, BAO, and a direct $H_0$ measurement. The authors use a likelihood-based approach to obtain best-fit parameters and apply the information criteria $AIC$ and $BIC$ (relative to the reference $\\Lambda$CDM model) to evaluate model merit, explicitly accounting for differing parameter counts. Their main finding is that the cosmological constant model, i.e., $\\Lambda$CDM, remains the most favored description of the data, with several dynamical models ($GCG$, $w$CDM, and $\\alpha$DE) still compatible but less economical, while others ($HDE$, $NGCG$, and $CPL$) fit but are not favored, and $NADE$, $DGP$, and $RDE$ are excluded by current observations. The results demonstrate that the Planck 2015 data together with geometric probes provide meaningful discrimination among smooth dark energy scenarios, informing model-building and guiding future observational efforts.

Abstract

We make a comparison for ten typical, popular dark energy models according to their capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant $w$ model, and the $α$ dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaplygin gas model, and the Chevalliear-Polarski-Linder model can still fit the current observations well, but from an economically feasible perspective, they are not so good. The new agegraphic dark energy model, the Dvali-Gabadadze-Porrati model, and the Ricci dark energy model are excluded by the current observations.

Comparison of dark energy models after Planck 2015

TL;DR

This study tackles the problem of identifying which dark energy models best explain the current expansion history by fitting ten representative models to a uniform data set that combines SN Ia from JLA, Planck 2015 distance priors, BAO, and a direct measurement. The authors use a likelihood-based approach to obtain best-fit parameters and apply the information criteria and (relative to the reference CDM model) to evaluate model merit, explicitly accounting for differing parameter counts. Their main finding is that the cosmological constant model, i.e., CDM, remains the most favored description of the data, with several dynamical models (, CDM, and DE) still compatible but less economical, while others (, , and ) fit but are not favored, and , , and are excluded by current observations. The results demonstrate that the Planck 2015 data together with geometric probes provide meaningful discrimination among smooth dark energy scenarios, informing model-building and guiding future observational efforts.

Abstract

We make a comparison for ten typical, popular dark energy models according to their capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant model, and the dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaplygin gas model, and the Chevalliear-Polarski-Linder model can still fit the current observations well, but from an economically feasible perspective, they are not so good. The new agegraphic dark energy model, the Dvali-Gabadadze-Porrati model, and the Ricci dark energy model are excluded by the current observations.

Paper Structure

This paper contains 23 sections, 61 equations, 11 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Methodology
  3. The observational data
  4. The SN data
  5. The CMB data
  6. The BAO data
  7. The $H_{0}$ measurement
  8. Dark energy models
  9. Cosmological constant model
  10. Dark energy models with equation of state parameterized
  11. Constant $w$ parametrization
  12. Chevallier-Porlarski-Linder parametrization
  13. Chaplygin gas models
  14. Generalized Chaplygin gas model
  15. New generalized Chaplygin gas model
  16. ...and 8 more sections

Figures (11)

  • Figure 1: The cosmological constant model: 68.3% and 95.4% confidence level contours in the $\Omega_{\rm{m}}$--$h$ plane.
  • Figure 2: The constant $w$ model: 68.3% and 95.4% confidence level contours in the $\Omega_{\rm{m}}$--$w$ and $\Omega_{\rm{m}}$--$h$ planes.
  • Figure 3: The Chevallier-Polarski-Linder model: 68.3% and 95.4% confidence level contours in the $w_{\rm{0}}$--$w_{\rm{a}}$ and $\Omega_{\rm{m}}$--$h$ planes.
  • Figure 4: The generalized Chaplygin gas model: 68.3% and 95.4% confidence level contours in the $A_{\rm{s}}$--$\beta$ and $A_{\rm{s}}$--$h$ planes.
  • Figure 5: The new generalized Chaplygin gas model: 68.3% and 95.4% confidence level contours in the $w$--$\eta$ and $\Omega_{\rm{de}}$--$h$ planes.
  • ...and 6 more figures