Time dependent gravitational constant in Chern Simons modified gravity

Two dark energy models and Λ are studied by taking into account the gravitational constant G is a time-dependent parameter in the framework of Chern-Simons modified gravity. It is found that the gravitational constant shown the increasing behavior proportional to those of the time parameter for each model. These models are compared with observational results by regulating the values of the parameters. Our investigations indicated that the model is generally attractive in nature while the other model Λ coincides to the repulsive situation and consequently match with the current scenario of the accelerating universe. We calculated the variation of G(t) which showed that it changes rapidly when the value of ω is taken between the limit . It is viewed that due to the composite influence of time-variable Λ and G(t), the universe expanded with acceleration. Further, it is estimated that the range for variation of G(t) with proper tuning of parameters α and β is given which match with Ia type supernova.