Astrophysics and Cosmology in Modified Gravity Theories

It is well known that general relativity is very successfully applied to cosmology, compact objects, and gravitational waves. However, observational data has increasingly challenged it. How can we explain, for example, the accelerated expansion of the universe without taking into account the so-called dark energy, whose origin and composition are not known? And as for dark matter, which is inferred to exist via a series of observational data, can we avoid it by replacing General Relativity with another theory of gravitation? Furthermore, is it possible to unambiguously explain the existence of massive neutron stars? Do the detections of gravitational waves made by the LIGO/Virgo/KAGRA collaboration really rule out alternative theories to General relativity?

There is a large series of papers in the literature that consider alternatives to General Relativity, the so-called Modified Gravity Theories, which aim to explain the most varied observational data. This Topical Collection aims to bring together articles in the most varied areas of astrophysics and cosmology, where different proposals for modified gravity theories are considered.

Keywords: dark matter, dark energy, inflation, cosmological models, neutrons stars, black holes, gravitational waves, modified gravity