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چکیده
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By using the spherical collapse model, we inves- tigate the growth of perturbations in time varying G cos- mologies. We study the transition redshift from early decel- erated expansion to current accelerated phase in varying G theories. Applying the Chevallier-Polarski-Linder parame- terization for dark energy, we study the effect of dark energy on the evolution of density perturbations in varying G cos- mologies. The main quantities in spherical collapse model, the linear overdensity parameter δ c and the virial overdensity vir are calculated. We compute the number of virialized dark matter haloes in the context of varying G cosmologies using the Sheth-Tormen mass function. Finally, we improve the spherical collapse model in varying G cosmologies by calculating the effects of shear and rotation on δ c and vir and the modification of mass function on the number count of dark matter haloes.
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