Destroying a Near-Extremal Kerr-Newman-AdS Black Hole with Test Particles

If radiative and self-force effects are neglected, we find that feeding a test particle into a near-extremal KerrNewman-Ad S black hole could lead to destroy their event horizon, giving rise to naked singularities. Hence radiative and self-force effects must be taken into account to further test cosmic censorship. Moreover, the allowed parameter range for this test particle is very narrow, this leaves the possibility of radiative and self-force effects considerations to cure the problem of WCC violation in Kerr-Newman-Ad S spacetime.     

Quasinormal modes of charged black holes in Einstein-Maxwell-Weyl gravity

We study quasinormal modes(QNMs)of charged black holes in the Einstein-Maxwell-Weyl(EMW)gravity by adopting the test scalar field perturbation.We find that the imaginary part of QNM frequencies is consistently negative for different angular parameters l,indicating that these modes always decay and are therefore stable.We do not observe a linear relationship between the QNM frequencyωand parameter p for these black holes,as their charge Q causes a nonlinear effect.We evaluate the massive scalar field perturbation in charged black holes and find that random long lived modes(i.e.,quasiresonances)could exist in this spectrum.