Visualization of frequency structures in gravitational wave signals

The frequency evolution of gravitational wave signals from the merger of compact binaries follows a slow build-up during the inspiral that peaks at merger, forming the characteristic "chirp" pattern in the signal's time-frequency map. Herein we introduce a framework for localizing further characteristic structures in the time-frequency space of gravitational wave signals using the continuous wavelet transform. We consider two example cases containing specific patterns in the postmerger stage of the signal that are rich with information on the source's physical nature: highly-inclined black hole binaries with asymmetric mass ratio, and neutron star binaries with postmerger remnant oscillations. It is demonstrated that the choice of quality factor Q plays a central role in distinguishing the postmerger features from that of the inspiral, with black hole systems preferring lower Q and neutron star systems preferring higher Q. To increase the detectability of the neutron star postmerger, we also explore stacking time-frequency maps from multiple events.