Investigation of Ringdown Behaviour in the Gravitational Waves from Binary Black Hole Mergers Detected by LIGO–Virgo–KAGRA.

We present a time-domain analysis of selected public LIGO–Virgo–KAGRA O4 binary black hole mergers. We study the detectability of gravitational wave higher harmonics of the final black holes based on the available parameter estimation samples. We test our method on strong events such as the GW250114 event and we apply it to other events with high enough signal to noise ratio. We use existing data analysis packages such as pyRing or Black Hole Perturbation Toolkit. Afterwards we compare our results with those obtained by LIGO–Virgo–KAGRA and search for possible differences.