Memory remains undetected: Updates from the second LIGO/Virgo gravitational-wave transient catalog

The LIGO and Virgo observatories have reported 39 new gravitational-wave detections during the first part of the third observation run, bringing the total to 50. Most of these new detections are consistent with binary black-hole coalescences, making them suitable targets to search for gravitational-wave memory, a nonlinear effect of general relativity. We extend a method developed in previous publications to analyze these events to determine a Bayes factor comparing the memory hypothesis to the no-memory hypothesis. Specifically, we calculate Bayes factors using two waveform models with higher-order modes that allow us to analyze events with extreme mass ratios and precessing spins, both of which have not been possible before. Depending on the waveform model, we find a combined lnBF₌₄₌=0. 024 or lnBF₌₄₌=0. 049 in favor of memory. This result is consistent with recent predictions that indicate O (2000) binary black-hole detections will be required to confidently establish the presence or absence of memory.