Synchronous frequencies of extremal Kerr black holes: Resonances, scattering, and stability

作     者：Maurício Richartz Carlos A. R. Herdeiro Emanuele Berti 

作者机构：Centro de Matemática Computação e Cognição Universidade Federal do ABC (UFABC) 09210-170 Santo André São Paulo Brazil Departamento de Física da Universidade de Aveiro and Center for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal Department of Physics and Astronomy The University of Mississippi University Mississippi 38677-1848 USA CENTRA Departamento de Física Instituto Superior Técnico Universidade de Lisboa Avenida Rovisco Pais 1 1049 Lisboa Portugal 

出 版 物：《Physical Review D》 (Phy. Rev. D)

年 卷 期：2017年第96卷第4期

页      面：044034-044034页

核心收录：

基　　金：Horizon 2020 Framework Programme, H2020, (, 690904) National Science Foundation, NSF, (AST-1716715, 1607130, PHY-1607130, AST-1716715, IF/00797/2014/CP1214/CT0012) Centro para a Investigação e Desenvolvimento em Matemática e Aplicações, (UID/MAT/04106/2013) Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP, (2013/09357-9) Fundação para a Ciência e a Tecnologia, FCT, (IF/00797/2014/CP1214/CT0012) 

主　　题：Classical black holes Fluids & classical fields in curved spacetime Gravitational waves 

摘      要：The characteristic damping times of the natural oscillations of a Kerr black hole become arbitrarily large as the extremal limit is approached. This behavior is associated with the so-called zero damped modes (ZDMs), and suggests that extremal black holes are characterized by quasinormal modes whose frequencies are purely real. Since these frequencies correspond to oscillations whose angular phase velocity matches the horizon angular velocity of the black hole, they are sometimes called “synchronous frequencies. Several authors have studied the ZDMs for near-extremal black holes. Recently, their correspondence to branch points of the Green’s function of the wave equation was linked to the Aretakis instability of extremal black holes. Here we investigate the existence of ZDMs for extremal black holes, showing that these real-axis resonances of the field are unphysical as natural black hole oscillations: the corresponding frequency is always associated with a scattering mode. By analyzing the behavior of these modes near the event horizon we obtain new insight into the transition to extremality, including a simple way to understand the Aretakis instability.