Search for gravitational wave ringdowns from perturbed black holes in LIGO S4 data

TL;DR

This paper reports a search for gravitational wave ringdowns from perturbed black holes in LIGO S4 data, setting upper limits on event rates but finding no detections, thus constraining black hole merger models.

Contribution

First search for black hole ringdowns in LIGO S4 data focusing on intermediate-mass black holes, establishing upper limits on their event rates.

Findings

No gravitational wave candidates detected.

Placed 90% confidence upper limits on ringdown event rates.

Sensitive to black holes with masses 10-500 solar masses up to 300 Mpc.

Abstract

According to general relativity a perturbed black hole will settle to a stationary configuration by the emission of gravitational radiation. Such a perturbation will occur, for example, in the coalescence of a black hole binary, following their inspiral and subsequent merger. At late times the waveform is a superposition of quasi-normal modes, which we refer to as the ringdown. The dominant mode is expected to be the fundamental mode, l=m=2. Since this is a well-known waveform, matched filtering can be implemented to search for this signal using LIGO data. We present a search for gravitational waves from black hole ringdowns in the fourth LIGO science run S4, during which LIGO was sensitive to the dominant mode of perturbed black holes with masses in the range of 10 Msun to 500 Msun, the regime of intermediate-mass black holes, to distances up to 300 Mpc. We present a search for gravitational waves from black hole ringdowns using data from S4. No gravitational wave candidates were found; we place a 90%-confidence upper limit on the rate of ringdowns from black holes with mass between 85 Msun and 390 Msun in the local universe, assuming a uniform distribution of sources, of 3.2 x 10^{-5} yr^{-1} Mpc^{-3} = 1.6 x 10^{-3}yr^{-1} L_{10}^{-1}, where L_{10} is 10^{10} times the solar blue-light luminosity.