arXiv subjects
Publications and source records attributed to Vassil K. Tinchev.
The following work presents a sufficiently general method for finding the parameters that characterise self-gravitating compact objects when their shadow contour is explicitly set. This method can be used in various algorithms to analyse experimental data for the shadow contour of specific compact objects.
We explore the shadow of certain class generalized Kerr black holes, which are non vacuum solutions of the Einstein equations with exotic matter. The images depend on the angular momentum of the compact object, the characteristic parameter $l$ of the model, and the inclination angle of the observer. The results are compared with the case of the Kerr black hole and the Kerr naked singularity.
Let two distinct $N$-simplexes be given in an Euclidean or pseudo-Euclidean $N+1$ dimensional space as each is defined by the coordinates of its $N+1$ vertexes. We consider the two families of $N$-spheres passing through the vertexes of the given $N$-simplexes and the set of couples of $N$-spheres (one belonging to first family and the other to the second one). The elements of this set have at least one common point; moreover, it is such that for the angle $α$ between the segments connecting that point and the centers of the corresponding $N$-spheres, there holds $\cos^{2}α=const$ for each of the elements of the defined set of $N$-spheres. In the present work we find the geometric place of all these common points, including the special cases when $\cos^{2}α$ is equal to $0$ or $1$.
We examine the shadow cast by a Kerr black hole pierced by a cosmic string. The observable images depend not only on the black hole spin parameter and the angle of inclination, but also on the deficit angle yielded by the cosmic string. The dependence of the observable characteristics of the shadow on the deficit angle is explored. The imprints in the black hole shadow left by the presence of a cosmic string can serve as a method for observational detection of such strings.