Confusing Head-On Collisions with Precessing Intermediate-Mass Binary Black Hole Mergers

We report a degeneracy between the gravitational-wave signals from quasi-circular precessing black-hole mergers and those extremely eccentric mergers, namely head-on collisions. Performing model selection on numerically simulated of collisions using models for binaries we find that, signal-to-noise ratios 15 25, typical Advanced LIGO observations, with respective total masses $M\in (125,300)M_\odot$ (200,440)M_\odot$ would be identified as intermediate-mass black hole binaries, located at much larger distance. Ruling out scenario require to perform currently nonexistent waveform collisions, together application astrophysically motivated priors (rare) occurrence events. show that in situations where standard parameter inference compact may component inside (outside) pair-instability supernova gap, true object merger outside (inside) this gap. briefly discuss potential implications these findings recent detection GW190521, which analyse detail [Phys. Rev. Lett. 126, 081101].