arXiv:1905.09260 [gr-qc]AbstractReferencesReviewsResources
A wider look at the gravitational-wave transients from GWTC-1 using an unmodeled reconstruction method
F. Salemi, E. Milotti, G. A. Prodi, G. Vedovato, C. Lazzaro, S. Tiwari, S. Vinciguerra, M. Drago, S. Klimenko
Published 2019-05-22Version 1
In this paper, we investigate the morphology of the events from the GWTC-1 catalog of compact binary coalescences as reconstructed by a generic method based on coherent excess power: we use an open-source version of the coherent WaveBurst (cWB) analysis pipeline, which does not rely on the detailed knowledge of the waveform models. cWB extracts the coherent response of the detectors' network to a generic gravitational wave, using loose bounds on the duration and bandwidth of the signal. This pipeline version reproduces the same results that were reported for cWB in recent publications by the LIGO and Virgo collaborations. The sky localization and waveform reconstruction performed by cWB are in a good agreement with the most accurate parameter estimates currently available, i.e. those produced by methods which exploit the detailed theoretical knowledge of the expected waveform for compact binary coalescences. However, in some cases cWB also detects features in excess in well-localized regions of the time-frequency plane. We have then devised and implemented a procedure to assess the probability that such deviations are significant. Out of the eleven events reported in the GWTC-1, there are two cases -- the events GW151012 and GW151226 -- where cWB detects an excess of coherent energy after the merger ($\Delta t \simeq 0.2$ s and $\simeq 0.1$ s, respectively) with p-values that call for further investigations ($0.004$ and $0.03$, respectively), though they are not sufficient to exclude noise fluctuations. We discuss the morphological properties and plausible interpretations of these features. We believe that the methodology described in the paper shall be useful in future searches and we look forward to its application to the the events of the ongoing observing run of the LIGO-Virgo Collaboration.