Near-extremal black holes in Weyl gravity: Quasinormal modes and geodesic instability

Mehrab Momennia and Seyed Hossein Hendi
Phys. Rev. D 99, 124025 – Published 18 June 2019

Abstract

Stability criteria of nearly extreme black holes in the perturbations level is one of the interesting issues in gravitational systems. Considering the nearly extreme conformal–de Sitter black holes, in this paper, we obtain an exact relation for the quasinormal modes of scalar perturbations. As a stability criteria, we find a lower bound on the event horizon radius which is corresponding to an upper bound on the value of the quasinormal frequencies. In addition, we show that the asymptotic behavior of quasinormal modes gives highly damped modes, which is important due to the possible connection between their real part and the Barbero-Immirzi parameter. We also obtain the Lyapunov exponent and the angular velocity of unstable circular null geodesics. Finally, we examine the validity of the relation between calculated quasinormal modes and unstable circular null geodesics.

  • Figure
  • Received 19 March 2019
  • Revised 22 May 2019

DOI:https://doi.org/10.1103/PhysRevD.99.124025

© 2019 American Physical Society

Physics Subject Headings (PhySH)

Gravitation, Cosmology & Astrophysics

Authors & Affiliations

Mehrab Momennia1,† and Seyed Hossein Hendi1,2,*

  • 1Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454, Iran
  • 2Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha, Iran

  • *Corresponding author. hendi@shirazu.ac.ir
  • m.momennia@shirazu.ac.ir

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Issue

Vol. 99, Iss. 12 — 15 June 2019

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