  We perturb the non-rotating BTZ black hole with a non-minimally coupled
massless scalar field, and we compute the quasinormal spectrum exactly. We
solve the radial equation in terms of hypergeometric functions, and we obtain
an analytical expression for the quasinormal frequencies. In addition, we
compare our analytical results with the 6th order semi-analytical WKB method,
and we find an excellent agreement. The impact of the nonminimal coupling as
well as of the cosmological constant on the quasinormal spectrum is briefly
discussed.
