We consider a class of black holes for which the area of the two-dimensional spatial cross section has a minimum on the horizon with respect to a quasiglobal (Krusckal-like) coordinate. If the horizon is regular, one can generate a tubelike counterpart of such a metric and smoothly glue it to a black hole region. The resulting composite space-time is globally regular, so all potential singularities under the horizon of the original metrics are removed. Such a space-time represents a black hole without an apparent horizon. It is essential that the matter should be nonvacuum in the outer region but vacuumlike in the inner one. As an example we consider the noninteracting mixture of vacuum fluid and matter with a linear equation of state and scalar phantom fields. This approach is extended to distorted metrics, with the requirement of spherical symmetry relaxed.
机构:
Shahid Bahonar Univ Kerman, Fac Phys, POB 76175, Kerman 7616913439, Iran
Inst Res Fundamental Sci IPM, Sch Phys, POB 19395-5531, Tehran, IranShahid Bahonar Univ Kerman, Fac Phys, POB 76175, Kerman 7616913439, Iran