Cosmological constraints and cosmic growth factor for ghost dark energy models in varying G theories

The Ghost Dark Energy (GDE) model in varying Newton's gravitational coupling (VG) theories is investigated. We first obtain the cosmological parameters of the model in modified FRW cosmology with varying G and then study the growth of matter perturbations in this formalism. Applying a Markov Chain Monte Carlo (MCMC) simulation and using the recent observational data, including Baryonic Acoustic Oscillation (BAO), the cluster X-ray Gas Mass Fraction (XGMF), Cosmic Microwave Background radiation (CMB), Growth Function for matter perturbation (GF), type Ia supernova (SNIa) and Hubble data, constraint results on GDE model parameters in VG theory are: Omega(0m) = 0.2751(-0.0104-0.0195)(+0.0104+0.0208), Omega(0d) = 0.7093(-0.0128-0.0245)(+0.0123+0.0229), beta = -0.0156-(+ 0.0041+0.0082)(0.0042-0.0078) and H-0 = 67.444(-0.873-1.829)+(0.899+1.757). The results for concordance Lambda CDM model are: Omega(0m) = 0.2762(-0.0099-0.0188)(+0.0097+0.0196), Omega(0d) = 0.7238(-0.0097-0.0196)(+0.0099+0.0188), and H-0 = 70.265(-0.797-1.515)(+0.797+1.575). We show that in this model the universe begins to accelerate at redshift z(t) similar or equal to 0.4 consistently in 1s level with observations. It shows that the growth rate of this model is well fitted by observational growth data as the Lambda CDM model.