Eur. Phys. J. Plus (2017) 132: 324
https://doi.org/10.1140/epjp/i2017-11596-3

Regular Article

Slowly decaying resonances of massive scalar fields around Schwarzschild-de Sitter black holes

¹ Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy & Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601, Opava, Czech Republic
² Ulugh Beg Astronomical Institute, Astronomicheskaya 33, 100052, Tashkent, Uzbekistan

^* e-mail: bobir.toshmatov@fpf.slu.cz

Received: 9 March 2017
Accepted: 19 June 2017
Published online: 26 July 2017

Abstract

We study in special limiting cases quasinormal modes of massive scalar fields in the Schwarzschild-de Sitter black hole backgrounds. We determine the lower limit on the mass parameter of the scalar field that allows the waves with quasinormal frequencies to propagate to infinity, showing that it depends on the spacetime parameters only. Then we discuss in the large multipole number limit quasinormal modes, whose frequencies can be directly related to the unstable circular photon geodesics. In the large scalar mass approximation, we demonstrate the new interesting phenomenon of slowly decaying resonances, that are strongly related to the maximum of the effective potential of the massive scalar field, which is located at the static radius of the Schwarzschild-de Sitter spacetimes, where the cosmic repulsion is just balanced by the black hole attraction.