相关论文: Double Images from a Single Black Hole

We study photon geodesics in topological solitons that have the same asymptotic properties as Schwarzschild black holes. These are coherent states in string theory corresponding to pure deformations of spacetime through the dynamics of…

We study the shadows cast by near-extremal Kerr-MOG black holes for different values of the parameter in modified gravity (MOG). In particular, we consider an isotropic emitter orbiting near such black holes and analytically compute the…

We revisit the geometry representing l collinear Schwarzschild black holes. It is seen that the black holes' horizons are deformed by their mutual gravitational attraction. The geometry has a string like conical singularity that connects…

Physical aspects of a static solution to the Einstein equations with two black holes are studied via ray tracing. The exact solution for this double Schwarzschild solution is known in explicit form. The black holes are separated by a…

The quantum extension of the Kruskal spacetime indicates the existence of a companion black hole in the universe earlier than ours. It is shown that the radiations from the companion black hole can enter its horizon, pass through the deep…

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 analysis of the shear induced by a single cluster on the images of a large number of background galaxies is all centered around the curl-free character of a well-known vector field that can be derived from the data. Such basic property…

The Primordial Black Holes (PBHs) are gradually involved into consideration as the phenomenon having reliable basis. We discuss here the possibility of their agglomeration into clusters that may have several prominent observable features.…

The visual distortion effects visible to an observer traveling around and descending to the surface of an extremely compact star are described. Specifically, trips to a ``normal" neutron star, a black hole, and an ultracompact neutron star…

We review the state of the evidence for the existence and observational appearance of supermassive black hole binaries. Such objects are expected from standard hierarchical galaxy evolution to form after two galaxies, each containing a…

The images of supermassive black holes surrounded by optically-thin, radiatively-inefficient accretion flows, like those observed with the Event Horizon Telescope, are characterized by a bright ring of emission surrounding the black-hole…

Black hole mimickers are possible alternatives to black holes, they would look observationally almost like black holes but would have no horizon. The properties in the near-horizon region where gravity is strong can be quite different for…

The Kerr-Bertotti-Robinson (Kerr-BR) black hole, a theoretical model of a rotating black hole immersed in a uniform magnetic field, has been proposed recently by Podolsky and Ovcharenko. This study investigates the optical characteristics…

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…

Light rays passing very close to black holes may wind several times before escaping. For any given electromagnetic source around the black hole, a distant observer would thus observe two infinite sequences of images on either side of the…

In this paper, the optical effects that occur near a Schwarzschild-like black hole (BH) with a Dehnen-type $(1,4,2)$ dark matter (DM) halo are explored. We first derive the photon sphere radius and obtain an analytical expression for the…

Light that grazes a black-hole event horizon can loop around one or more times before escaping again, resulting for distance observers in an infinite sequence of ever fainter and more delayed images near the black hole shadow. In the case…

The high-energy absorption cross section of the Schwarzschild black hole is well approximated, in the eikonal regime, by the sum of two terms: the geometrical cross section of the black hole photon sphere and the contribution of a sinc…

According to recent conjectures on the existence of large extra dimensions in our universe, black holes may be produced during the interaction of Ultra High Energy Cosmic Rays with the atmosphere. However, and so far, the proposed…

Recently, two new quantum-corrected black hole models satisfying covariance have been proposed within the framework of effective quantum gravity. In this paper, we study how the quantum parameter $\zeta$ affects the optical properties of…