I am reading LIGO's new discovery of gravitational waves by black hole merger. During the merger, two phases are not hard to manipulate by hand or on PC, the in-spiral and ring-down phases.
During the violent merging before ring-down, the binary contacts each other closely and excite gravitational perturbations around the final Kerr space-time. If I understand correctly, this violent excitation includes frequencies over a large range, possibly well beyond the hundreds Hertz seen by LIGO. They only observed that low frequency in ring-down, only because this mode damps the slowest.
Now comes the question: How much in fraction (or amplitude) are the modes excited during merging? If some high frequency mode get excited with a very large amplitude, shouldn't they also show up during the early ring-down in data, even though they damps faster?
Thank you very much!