Recently, inhomogeneous generalizations of the Friedmann–Lemaître–Robertson–Walker
(FLRW) cosmological models have gained interest in the astrophysical community and are …

In this work, we performed a systematic study of the Symmergent gravity (SG) in a black hole
(BH) environment. Being an emergent gravity model in which gravity emerges to restore the …

From the microscopic point of view, realistic black holes are time-dependent and the
teleological concept of the event horizon fails. At present, the apparent or trapping horizon …

Event horizons are (generically) not physically observable. In contrast, apparent horizons
(and the closely related trapping horizons) are generically physically observable—in the …

Recently Kaloper, Kleban, and Martin reexamined the McVittie solution and argued, contrary
to a very widely held belief, that the solution contains a black hole in an expanding universe …

We investigate the effect of the cosmological constant on the angular size of a black hole
shadow. It is known that the accelerated expansion which is created by the cosmological …

The bizarre behavior of the apparent (black hole and cosmological) horizons of the McVittie
spacetime is discussed using, as an analogy, the Schwarzschild-de Sitter-Kottler spacetime …

We provide a thorough examination of the conditions for the existence of back-reaction and
an'effective'acceleration (in the context of Buchert's averaging formalism) in regular generic …

Astronomical observations reveal hierarchical structures in the universe, from galaxies,
groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales …

Structure formation in the Szekeres model is investigated. Since the Szekeres model is an
inhomogeneous model with no symmetries, it is possible to examine the interaction of …