The weak equivalence principle (WEP) is the cornerstone of general relativity (GR). Testing
it is thus a natural way to confront GR to experiments, which has been pursued for four …

We investigate whether photon ring observations in black hole imaging are able to
distinguish between the Kerr black hole in general relativity and alternative black holes that …

General relativity is one of the pillars of modern physics. For decades, the theory has been
mainly tested in the weak-field regime with experiments in the solar system and radio …

The continuum-fitting and the iron-line methods are currently the two leading techniques for
measuring the spins of accreting black holes. In the past few years, these two methods have …

Einstein's theory of General Relativity is one of the pillars of modern physics. For decades,
the theory has been mainly tested in the weak field regime with experiments in the Solar …

Bumblebee gravity is one of the simplest gravity theories with spontaneous Lorentz
symmetry breaking. Since we know a rotating black hole solution in bumblebee gravity, we …

The analysis of the properties of the X-ray radiation emitted from geometrically thin accretion
disks around black holes can be a powerful tool to test General Relativity in the strong field …

We studied the massive and massless particle's motion around Schwarzschild acoustic
black hole and showed that the tuning parameter of the spacetime weakens the gravitational …

Inspired by special relativity, we put forward the idea the mass of particles is an emergent
phenomenon. It assumed that that matter is composed by two groups of massless particles …

The universality of free fall or what is also known by the weak principle equivalence is the
essential point and the cornerstone of the theory of general relativity. Several experiments …