Gravitational wave echoes search with combs

Gravitational wave echoes may provide a smoking gun signal for new physics in the immediate vicinity of black holes. As quasiperiodic time, are characterized by nearly constant time delay, and its precise measurement can help reveal Planck-scale deviation outside would-be horizon. Different search methods have been developed this signal, while searches suffer from large theoretical uncertainties echo waveform associated with near-horizon physics. On other hand, coherent combination number pulses gives rise to generic narrow resonance structure amplitude frequency. This pattern sets complementary target echoes, delay is inversely related average spacing. A uniform comb has proposed look rather model-independent way. In paper, we develop Bayesian algorithm based on combs, where phase-marginalized likelihood plays an essential role. The validated injections detector noise Advanced LIGO. With special treatments non-Gaussian artifacts, outliers log Bayes factor distribution properly removed. An not significantly below detectable, be determined very high precision. We perform real gravitational strain data first observing run find no clear evidence comblike GW150914 GW151012.