Search for continuous gravitational waves from 20 accreting millisecond X-ray pulsars in O3 LIGO data

Understand

Results are presented of searches for continuous gravitational waves from 20 accreting millisecond X-ray pulsars with accurately measured spin frequencies and orbital parameters, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors.

• The search algorithm uses a hidden Markov model, where the transition probabilities allow the frequency to wander according to an unbiased random walk, while the $\mathcal{J}$-statistic maximum-likelihood matched filter tracks the binary orbital phase.
• Three narrow sub-bands are searched for each target, centered on harmonics of the measured spin frequency.
• The search yields 16 candidates, consistent with a false alarm probability of 30% per sub-band and target searched.