相关论文: Spacetime Measurements with the Photon Ring

In this paper we consider the possibility of measuring the corrections induced by the square of the parameter a_g of the Kerr metric to the general relativistic deflection of electromagnetic waves and time delay in an Earth based…

Combined with the observation of M87*, shadow has gradually became a promising test of the black hole nature. Recently, EHT collaboration gave new constraints on the shadow size at 68\% confidence levels. In this work, we consider the new…

Black hole shadow images are primarily determined by the properties of photon spheres and can exhibit degeneracies across different spherically symmetric spacetime geometries. We show that time delay observables associated with higher-order…

Recent strong-field regime tests of gravity are so far in agreement with general relativity. In particular, astrophysical black holes appear all to be consistent with the Kerr spacetime, but the statistical error on current observations…

Recent observations of the near-horizon regions of BHs, particularly the images captured by the Event Horizon Telescope (EHT) collaboration, have greatly advanced our understanding of gravity in extreme conditions. These images reveal a…

In general relativity, the Kerr metric uniquely represents the geometry surrounding an isolated, rotating black hole. An identification of significant non-Kerr features in some astrophysical source would then provide a `smoking-gun' for the…

We establish a thermodynamic-optical duality that directly bridges the semiclassical quantum evaporation of black holes with their classical macroscopic geometry. By employing a diffeomorphic inversion, we re-parameterize the intrinsic…

In this paper, we investigate the shadow and optical appearance of the hairy Kerr black hole illuminated by a thin accretion disk, the materials of which outside the innermost stable circular orbit (ISCO) move on the equatorial circular…

We investigate photon-axion conversion in the vicinity of rotating Kerr black holes where strong gravity traps photons on near-circular trajectories, effectively enhancing the path length. We explore the observable signatures of such a…

In recent years, the shape of the photon ring in black holes images has been argued to provide a sharp test of the Kerr hypothesis for future black hole imaging missions. In this work, we confront this proposal to beyond Kerr geometries and…

In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size…

We propose a new test of strong-field general relativity (GR) based on the universal interferometric signature of the black hole photon ring. The photon ring is a narrow ring-shaped feature, predicted by GR but not yet observed, that…

It is thought that the spacetime metric around astrophysical black holes is well described by the Kerr solution of Einstein's gravity. However, a robust observational evidence of the Kerr nature of these objects is still lacking. Here we…

\begin{abstract} Using the Keeton and Petters approach, we determine the deflection angle. We also investigate the motion of photons around a parameterized black hole in the presence of non-magnetized cold plasma by using a new ray-tracing…

This work investigates additional gravitational features of a newly proposed black hole spacetime within Kalb-Ramond gravity, incorporating non-commutative corrections arising from a gauge-theoretic approach recently introduced in the…

X-ray reflection spectroscopy is a powerful tool for testing the Kerr hypothesis and probing the strong gravity regime around accreting black holes. Most tests of General Relativity (GR) assume that the spacetime around a black hole is…

In this paper we compute the Arnowitt-Deser-Misner (ADM) mass, the angular momentum and the charge of the Kerr black hole solution in the scalar-tensor-vector gravity theory [known as the Kerr-MOG (modified-gravity) black hole…

General relativity predicts that gravitational lensing near black holes will produce narrow "photon rings" on images. Building on recent work of Johnson, Lupsasca et al. focusing on circular rings, I calculate the long-baseline…

In a recent work on rotating black hole shadows [Phys. Rev. D{\bf 101}, 084029 (2020)], we proposed a new approach for calculating size and shape of the shadows in terms of astrometrical observables with respect to finite-distance…

The standard Black Holes (BHs) in General Relativity, as well as other ultra-compact objects (with or without an event horizon) admit planar circular photon orbits. These light rings (LRs) determine several spacetime properties. For…