Gravitational-wave templates are used to do what in detections of BH mergers?

• A. Estimate the mass of nearby stars.
• B. Calibrate telescope exposure times.
• C. Predict solar eclipses.
• D. Match observed signals to predicted waveforms to identify events.

Answer: (D)

Gravitational-wave templates are used to match observed signals to predicted waveforms to identify events. In practice, scientists generate a wide set of theoretical waveforms describing how merging black holes should look in the detectors, based on general relativity. The real data, which are often buried in noise, are then scanned with these templates through a process called matched filtering. By measuring how well each predicted waveform matches the data, researchers can pull out true gravitational-wave signals and determine which template best describes the event. That best match not only signals that a merger happened but also provides estimates of the source properties, like the black holes’ masses, spins, distance, and orientation. The other activities—estimating masses of nearby stars, calibrating telescope exposures, or predicting solar eclipses—don’t use this waveform-matching approach to identify gravitational-wave mergers, which is why the template method is central to detections.