Directed searches for gravitational waves from ultralight bosons

Black-hole superradiance may make it possible to detect or constrain yet-undiscovered ultralight bosons using gravitational waves. In this talk, I will describe how we may achieve this with ground-based detectors by searching for continuous gravitational waves from known black holes. This includes black holes in x-ray binaries and remnants from compact-binary mergers. I will present results from the recovery of simulated signals from noisy data using hidden Markov models. This efficient data analysis technique will make it possible to target remnants from compact-binary mergers localized with at least three instruments like LIGO and Virgo. I will present sensitivity projections for 2G and 3G ground-based detectors and, in closing, discuss specific potential targets and their associated challenges.