**Publication date:** Sep 2017

**Abstract:**

We study scalar and electromagnetic perturbations of a family of

nonsingular nonrotating black hole spacetimes that are solutions in a

large class of conformally invariant theories of gravity. The effective

potential for scalar perturbations depends on the exact form of the

scaling factor. Electromagnetic perturbations do not feel the scaling

factor, and the corresponding quasinormal mode spectrum is the same as

in the Schwarzschild metric. We find that these black hole metrics are

stable under scalar and electromagnetic perturbations. Assuming that the

quasinormal mode spectrum for scalar perturbations is not too different

from that for gravitational perturbations, we can expect that the

calculation of the quasinormal mode spectrum and the observation with

gravitational wave detectors of quasinormal modes from astrophysical

black holes can constrain the scaling factor and test these solutions.

**Authors:**

Toshmatov, Bobir; Bambi, Cosimo; Ahmedov, Bobomurat; Stuchlík, Zdeněk; Schee, Jan;