Evolution of spherical overdensities in new agegraphic dark energy model

We study the structure formation by investigating the spherical collapse model in the context of new agegraphic dark energy (NADE) model in flat FRW cosmology. We compute the perturbational quantities g(a), delta(c)(z(c)), lambda(z(c)), xi(z(c)), Delta(vir)(z(c)), log[vf(v)] and log[n(k)] for the NADE model and compare the results with those of EdS and.CDM models. We find that there is a dark energy-dominated universe at low redshifts and a matter-dominated universe at high redshifts in agreement with the observations. Also, the size of structures, the overdense spherical region, and the halo size in the NADE model are found to be smaller, denser, and larger than those of EdS and.CDM models. We compare our results with the results of tachyon scalar field and holographic dark energy models.