Cosmological Constraints on New Agegraphic Dark Energy

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In this work, we consider the cosmological constraints on the new agegraphic dark energy (NADE) proposed in arXiv:0708.0884, by using the observational data of type Ia supernovae (SNIa), the shift parameter from cosmic microwave background (CMB) and the baryon acoustic oscillation (BAO) peak from large scale structures (LSS).

• Thanks to its special analytic features in the radiation-dominated and matter-dominated epochs, NADE is a single-parameter model in practice because once the single model parameter $n$ is given, all other physical quantities of NADE can be determined correspondingly.
• The joint analysis gives the best-fit value (with $1\sigma$ uncertainty) $n=2.716^{+0.111}_{-0.109}$, and the derived $\Omega_{m0}$, $\Omega_{q0}$ and $w_{q0}$ (with $1\sigma$ uncertainties) are $0.295^{+0.020}_{-0.020}$, $0.705^{+0.020}_{-0.020}$ and $-0.794^{+0.006}_{-0.005}$, respectively.
• In addition, we find that the coincidence problem could be solved naturally in the NADE model provided that $n$ is of order unity.