2021/04/30 by Xin-Chang Cai, Yan-Gang Miao
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Black hole (networking) #Charge (physics) #Dimensionless quantity #Massless particle #Mathematical physics #Physics #Pulsars and Gravitational Waves Research #Quantum electrodynamics #Quantum mechanics #Scalar field #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.103.124050
published as Phys. Rev. D 103, 124050 (2021) · v1: 20 pages, 9 figures; v2: 24 pages, 11 figures, 2 tables, final version to appear in Physical Review D
openalex created_date 2021/04/26 · arxiv created 2021/05/31 · openalex publication_date 2021/06/22 · arxiv updated 2021/06/30 · openalex updated_date 2026/08/05
We obtain a type of Ay'on-Beato-Garc'\ia (ABG) related black hole solutions with five parameters: the mass m, the charge q, and three dimensionless parameters \ensuremathα, \ensuremathβ and \ensuremathγ associated with nonlinear electrodynamics. We find that this type of black hole is regular under the conditions: \ensuremathα\ensuremathγ\ensuremath≥6, \ensuremathβ\ensuremathγ\ensuremath≥8, and \ensuremathγ>0. Here we focus on the saturated case: \ensuremathα=6/\ensuremathγ and \ensuremathβ=8/\ensuremathγ, such that only three parameters m, q and \ensuremathγ remain, which leads to a new family of ABG black holes. For such a family of black holes, we investigate the influence of the charge q and the parameter \ensuremathγ on the horizon radius and the Hawking temperature. In addition, we calculate the quasinormal mode frequencies of massless scalar field perturbations by using the sixth-order WKB approximation method and the unstable circular null geodesic method in the eikonal limit. On the one hand, our results show that the increase of the charge q makes the scalar waves decay faster at first and then slowly except for the case of \ensuremathγ=2. On the other hand, they show that the increase of the parameter \ensuremathγ makes the scalar waves decay at first sharply and then slowly. In particular, \ensuremathγ=1 can be regarded as the critical value for the transition from an unstable configuration to a stable one. Finally, we compute the shadow radius for the new family of ABG black holes and use the shadow data of the M87* black hole detected by the Event Horizon Telescope to provide an upper limit on the charge q of the new black holes. We find that the increase of the charge q makes the shadow radius decrease monotonically, while the increase of the parameter \ensuremathγ makes the shadow radius increase at first rapidly and then almost remain unchanged, especially the parameter \ensuremathγ has a significant impact on the shadow radius when it is less than one. Moreover, using the shadow data of the M87* black hole, we find that the upper limit of the charge q increases rapidly at first and then slowly but does not exceed the mass of the M87* black hole at last when the parameter \ensuremathγ is increasing and going to infinity, and that the data restrict the frequency range of the fundamental mode with l=1 to 1.4\ifmmode×\else\texttimes\fi10^\ensuremath-6 Hz\ensuremath∼1.9\ifmmode×\else\texttimes\fi10^\ensuremath-6 Hz.