Searching for Intermediate-Mass Binary Black Hole Mergers in the Fourth Observation Run

General Relativity predicts that higher-order modes exist in gravitational waves from binary black hole mergers. They are omitted in current matched filtering search pipelines to reduce computational cost. Higher-order modes become non-negligible for inclined asymmetric systems with masses larger than 100 solar masses; thus, the waveform templates in the current search pipeline are not suited for them. A method adapted for these systems, implementing higher-order modes and other statistics, has been developed and was deployed on data from the third observation run of Advanced LIGO. We present the same method adapted to search for these systems in the fourth observation run, where more of these systems are expected to be detectable. GW231123 is a notable event in this regime and has proven its value in sophisticated tests of General Relativity and more. More detections of these events will also open the gate to other exciting topics, such as population analyses of intermediate-mass black holes, which were not expected to have formed from supernovae.