Magnetic tunnels (wormholes) in astrophysics

We consider models of a wormhole (i) maintained by an electromagnetic field, taking into account quantum vacuum corrections to the equation of state, (ii) maintained by a combination of the magnetic field and phantom energy, with a spherically symmetrical equation of state, and (iii) with a magnetic field and phantom matter with an anisotropic equation of state. It is shown that the quantum corrections and the density and exoticity of phantom energy or matter can be as small as is desired. For an external observer, the entrance to the tunnel appears to be a magnetic monopole of macroscopic size. The accretion of ordinary matter onto the entrance to the tunnel may result in the formation of a black hole with a radial magnetic field. We consider the possibility that some active galactic nuclei and Galactic objects may be current or former entrances to magnetic wormholes. We consider the possible existence of a broad mass spectrum for wormholes, from several billion solar masses to masses of the order of 2 kg. The Hawking effect (evaporation) does not operate in such objects due to the absence of a horizon, making it possible for them to be retained over cosmological time intervals, even if their masses are smaller than 10¹⁵ g. We also discuss a model for a binary system formed by the entrances of tunnels with magnetic fields, which could be sources of nonthermal radiation and γ-ray bursts.