Analysis of Ringdown Overtones in GW150914

Understand

We analyze GW150914 post-merger data to understand if ringdown overtone detection claims are robust.

• We find no evidence in favor of an overtone in the data after the waveform peak.
• Around the peak, the Bayes factor does not indicate the presence of an overtone, while the support for a nonzero amplitude is sensitive to changes in the starting time much smaller than the overtone damping time.
• This suggests that claims of an overtone detection are noise-dominated.