Cosmological constraints on new agegraphic dark energy

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 la 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-para meter 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(-0.109)(+0.111) 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(-0.005)(+0.006), respectively. In addition, we find that the coincidence problem could be solved naturally in the NADE model provided that n is of order unity. (C) 2008 Elsevier B.V. All rights reserved.