Relativistic reflection features are commonly observed in the X-ray spectra of accreting black
holes. In the presence of high quality data and with the correct astrophysical model, X-ray …

Einstein's theory of general relativity is one of the pillars of modern physics and it is our
standard framework for describing gravitational fields and the spacetime structure. So far …

Wormholes are hypothetical topologically-non-trivial structures of spacetime. From the
theoretical point of view, the possibility of their existence is challenging but cannot be ruled …

We report the existence of novel static spherical black hole solutions in a vector–tensor
gravitational theory called the bumblebee gravity model, which extends the Einstein …

In the disk–corona model, the X-ray spectrum of a stellar-mass black hole in an X-ray binary
is characterized by three components: a thermal component from a thin and cold accretion …

We have considered a time-like geodesics in the background of rotating Simpson–Visser
(SV) black hole (BH) to examine structure of the horizon and ergosphere. The innermost …

The presence of spacetime singularities in physically relevant solutions of the Einstein
Equations is normally interpreted as a symptom of the breakdown of classical general …

We present an analysis of the relativistic reflection spectra of GX 339–4 during the hard-to-
soft transition of its 2021 outburst observed by Insight–HXMT. The strong relativistic …

Gravitational-wave observations of binary black holes provide a suitable arena to test the
fundamental nature of gravity in the strong-field regime. Using the data of the inspiral of 29 …

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 …