Constraints of extended gravity theory in the regime of Universe accelerated extension: turnaround radius

Applying the definition of the turnaround radius and the fact that the best agreement with observational data on extragalactic scales is currently provided by general relativity with the cosmological constant we consider the behaviour of spherically symmetric solutions of the Horndeski and Dvali-Gabadadze-Poratti models on these scales. Therefore, the conditions on the turning radius together with astronomical data for galaxy clusters allow us to place additional constraints on the parameters of extended gravity theories.