ABSTRACT

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 _ { m 0 } , \Omega _ { q 0 } and w _ { q 0 } ( 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 .