Abstract

Accordingto general relativity a perturbed black hole will settle toa stationary configuration by the emission of gravitational radiation. Sucha perturbation will occur, for example, in the coalescence ofa black hole binary, following their inspiral and subsequent merger.At late times the waveform is a superposition of quasinormalmodes, which we refer to as the ringdown. The dominantmode is expected to be the fundamental mode, l=m=2. Sincethis is a well-known waveform, matched filtering can be implementedto search for this signal using LIGO data. We presenta search for gravitational waves from black hole ringdowns inthe fourth LIGO science run S4, during which LIGO wassensitive to the dominant mode of perturbed black holes withmasses in the range of 10M[sun] to 500M[sun], the regimeof intermediate-mass black holes, to distances up to 300 Mpc. Wepresent a search for gravitational waves from black hole ringdownsusing data from S4. No gravitational wave candidates were found;we place a 90%-confidence upper limit on the rate ofringdowns from black holes with mass between 85M[sun] and 390M[sun]in the local universe, assuming a uniform distribution of sources,of 3.2×10-5 yr-1 Mpc-3=1.6×10-3 yr-1L10-1,where L10 is 1010 times the solar blue-light luminosity.