Abstract The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good
description of a wide range of astrophysical and cosmological data. However, there are a …

We review applications of string theory to cosmology, from primordial times to the present-
day accelerated expansion. Starting with a brief overview of cosmology and string …

Horizon-scale images of black holes (BHs) and their shadows have opened an
unprecedented window onto tests of gravity and fundamental physics in the strong-field …

A number of challenges to the standard Λ CDM model have been emerging during the past
few years as the accuracy of cosmological observations improves. In this review we discuss …

The Swampland program aims to distinguish effective theories which can be completed into
quantum gravity in the ultraviolet from those which cannot. This article forms an introduction …

General relativity (GR) was proven via the direct detection of gravitational waves from the
mergers of the binary black holes and binary neutron stars by the advanced LIGO and …

Ultralight bosons can affect the dynamics of spinning black holes (BHs) via superradiant
instability, which can lead to a time evolution of the supermassive BH shadow. We study …

The tension between early and late Universe probes of the Hubble constant has motivated
various new FLRW cosmologies. Here, we reanalyse the Hubble tension with a recent age …

Cosmography can be considered as a sort of a model-independent approach to tackle the
dark energy/modified gravity problem. In this review, the success and the shortcomings of …

Black hole (BH) shadows can be used to probe new physics in the form of ultralight particles
via the phenomenon of superradiant instability. By directly affecting the BH mass and spin …