Development and Application of a Detection System for a Novel Class of Gravitational-Wave Transients

We previously described the development of a detection system for a novel class of transient gravitational-wave sources taking the form of Cherenkov-like bursts. Here, we have applied the system to the data of the LIGO/Virgo/KAGRA O3 science run, and report a null result. The ad hoc waveform model is motivated by the conjectured emission of gravitational waves from a curvature source moving at super-luminal speed, and while there is no plausible natural or artificial source of such waves, we nevertheless use the null result to infer a tongue-in-cheek upper bound on the number density of near-Earth transits of spacecraft travelling at warp speed. The upper bound is parameterized in terms of the trajectory's impact parameter, the vehicle's engine power,and speed. These quantities can be connected to statements made in science fiction allowing us to translate the upper bound into a bound on the number density of specific types of spacecraft from, for example, Star Trek or Star Wars. Although most suitable for entertainment purposes, these constraints might find use being folded into a Bayesian inference type estimate on the number of extra-terrestrial civilizations in the galaxy.