Search for continuous gravitational waves from 20 accreting millisecond xray pulsars in O3 LIGO data
Abstract
Results are presented of searches for continuous gravitational waves from 20 accreting millisecond xray 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 J statistic maximumlikelihood matched filter tracks the binary orbital phase. Three narrow subbands 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 subband and target searched. These candidates, along with one candidate from an additional targetofopportunity search done for SAX J 1808.4 −3658 , which was in outburst during one month of the observing run, cannot be confidently associated with a known noise source. Additional followup does not provide convincing evidence that any are a true astrophysical signal. When all candidates are assumed nonastrophysical, upper limits are set on the maximum wave strain detectable at 95% confidence, h_{0}^{95 %}. The strictest constraint is h_{0}^{95 %}=4.7 ×10^{26} from IGR J 17062 −6143 . Constraints on the detectable wave strain from each target lead to constraints on neutron star ellipticity and r mode amplitude, the strictest of which are ε^{95 %}=3.1 ×10^{7} and α^{95 %}=1.8 ×10^{5} respectively. This analysis is the most comprehensive and sensitive search of continuous gravitational waves from accreting millisecond xray pulsars to date.
 Publication:

Physical Review D
 Pub Date:
 January 2022
 DOI:
 10.1103/PhysRevD.105.022002
 arXiv:
 arXiv:2109.09255
 Bibcode:
 2022PhRvD.105b2002A
 Keywords:

 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 40 pages, 6 figures. This version contains minor typographical revisions to match published article