we investigate the growth of matter density perturbations as well as the generalized second law (gsl) of thermodynamics in the framework of f(r)-gravity. we consider a spatially flat frw universe filled with the pressureless matter and radiation which is enclosed by the dynamical apparent horizon with the hawking temperature. for some viable f(r) models containing the starobinsky, hu-sawicki, exp...

Weak lensing (WL) promises to be a particularly sensitive probe of both the growth of large-scale structure as well as the fundamental relation between matter density perturbations and metric perturbations, thus providing a powerful tool with which we may constrain modified theories of gravity (MG) on cosmological scales. Future deep, wide-field WL surveys will provide an unprecedented opportun...

We consider perturbative modifications of the Friedmann equations in terms of energy density corresponding to modified theories of gravity proposed as an alternative route to comply with the observed accelerated expansion of the universe. Assuming that the present matter content of the universe is a pressureless fluid, the possible singularities that may arise as the final state of the universe...

We study cosmologies in modified theories of gravity considering Lagrangian density f(R) which is a polynomial function of scalar curvature (R) in the Einstein-Hilbert action in vacuum. The field equation obtained from the modified action corresponding to a Robertson-Walker metric is highly non-linear and not simple enough to obtain analytic solution. Consequently we adopt a numerical technique...

When bars form within galaxy formation simulations in the standard cosmological context, dynamical friction with dark matter (DM) causes them to rotate rather slowly. However, almost all observed galactic are fast terms of ratio between corotation radius and bar length. Here, we explicitly display an $8\sigma$ tension distribution this that EAGLE simulation at redshift 0. We also compare evolut...