相关论文: Black Hole Shadows, Photon Rings, and Lensing Ring…

Images of supermassive black holes produced using very long baseline interferometry provide a pathway to directly observing effects of a highly curved spacetime, such as a bright ``photon ring'' that arises from strongly lensed emission. In…

The apparent shadow of a black hole provides one of the most direct probes of strong-field general relativity. While the shadow size in asymptotically flat spacetimes is well understood, the influence of cosmic expansion on its apparent…

Due to the gravitational lensing effect, a black hole casts a shadow larger than its horizon over a bright background, and the shape and size can be calculated. The Event Horizon Telescope collaboration has produced the first direct image…

We examine the observational discrepancies of two widely used models describing anisotropic (dark) matter distributions around a black hole, focusing on their photon spheres, shadow radii, and lensing observables. The models considered are…

The Event Horizon Telescope (EHT) has significantly advanced our ability to study black holes, achieving unprecedented spatial resolution and revealing horizon-scale structures. Notably, these observations feature a distinctive dark…

We study the photon's motion around a black hole in the presence of a plasma whose density is a function of the radius coordinate by a renewed ray-tracing algorithm and investigate the influence of the plasma on the shadow of the black…

Can the observation of the "shadow" allow us to distinguish a black hole from a more exotic compact object? We study the motion of photons in a class of vacuum static axially-symmetric space-times that is continuously linked to the…

We develop a "dual cone" model for millimeter wavelength emission near a spinning black hole. The model consists of optically thin, luminous cones of emission, centered on the spin axis, which are meant to represent jet walls. The resulting…

Very-long baseline interferometric observations have resolved structure on scales of only a few Schwarzschild radii around the supermassive black holes at the centers of our Galaxy and M87. In the near future, such observations are expected…

An analytical model of a parabolic screen illuminating a black hole is proposed. This allows to avoid naturally the appearance of edge effects associated with photons moving along the plane of the screen. The temperature distribution along…

We study the shadow cast by the H$D$ Schwarzschild-Tangherlini black hole, and analytically calculate the influence of extra dimensions on the shadow of a black hole. A black hole casts a shadow as an optical appearance because of its…

We analyze gravitational lensing, in particular the shadow and photon rings, in the Ernst spacetime, also known as the Schwarzschild-Melvin spacetime, which describes a Schwarzschild black hole immersed in a homogenous magnetic field.…

We have studied photon motion around axially symmetric rotating Kerr black hole in the presence of plasma with radial power-law density. It is shown that in the presence of plasma the observed shape and size of shadow changes depending on…

The horizon-scale images of black holes obtained with the Event Horizon Telescope have provided new probes of their metrics and tests of General Relativity. The images are characterized by a bright, near circular ring from the…

A compact object illuminated by background radiation produces a dark silhouette. The edge of the silhouette or shadow (alternatively, the apparent boundary or the critical curve) is commonly determined by the presence of the photon sphere…

Following the 2019 release by the Event Horizon Telescope Collaboration of the first pictures of a supermassive black hole, there has been an explosion of interest in black hole images, their theoretical interpretation, and their potential…

Here we provide shadow images of a Kerr-like black hole (BH) in cold dark matter (CDM) halo illuminated with a celestial light source and a thin accretion disk. The impact of spin parameter, critical density and the scale radius on the…

Since a black hole does not emit light from its interior, nor does it have a surface on which light from nearby sources can be reflected, observational study of black hole physics requires observing the gravitational impact of the black…

Zhang have obtained recently a twisted rotating black hole metric, which is a vacuum solution in four-dimensional Einstein gravity. This black hole solution has a rotation parameter, but without the total angular moment. Here, we have…

This work devotes to investigate the dynamical emergence of black hole shadow from gravitational lensing in dynamical spacetime by using the collapsing boson star. Two characterized scenarios are adopted with or without considering the time…