Dynamics of charged particles and magnetic dipoles around magnetized quasi-Schwarzschild black holes

摘要

In the present paper, we have investigated the motion of charged particles together with magnetic dipoles to determine how well the spacetime deviation parameter $$epsilon $$ ? and external uniform magnetic field can mimic the spin of a rotating Kerr black hole. Investigation of charged particle motion has shown that the deviation parameter $$epsilon $$ ? in the absence of an external magnetic fields can mimic the rotation parameter of the Kerr spacetime up to $$a/M pprox 0.5$$ a / M ≈ 0.5 . The combination of an external magnetic field and deviation parameter can do even a better job mimicking the rotation parameter up to $$a/Msimeq 0.93$$ a / M ? 0.93 , which corresponds to the rapidly rotating case. Study of the dynamics of the magnetic dipoles around quasi-Schwarzschild black holes in the external magnetic field has shown that there are degeneracy values of the ISCO radius of test particles at $$epsilon _{cr}epsilon ge 0.35$$ ? cr ? ≥ 0.35 which may lead to two different values of the innermost stable circular orbit (ISCO) radius. When the deviation parameter is in the range of $$epsilon in (-1, 1)$$ ? ∈ ( - 1 , 1 ) , it can mimic the spin of a rotating Kerr black hole in the range $$a/M in (0.0537, 0.3952)$$ a / M ∈ ( 0.0537 , 0.3952 ) for magnetic dipoles with values of the magnetic coupling parameter $$eta in [-0.25, 0.25]$$ β ∈ [ - 0.25 , 0.25 ] in corotating orbits.