PHYSICAL REVIEW D
Results are presented from a semicoherent search for continuous gravitational waves from the brightest low-mass X-ray binary, Scorpius X-1, using data collected during the first Advanced LIGO observing run. The search combines a frequency domain matched filter (Bessel-weighted F-statistic) with a hidden Markov model to track wandering of the neutron star spin frequency. No evidence of gravitational waves is found in the frequency range 60-650 Hz. Frequentist 95% confidence strain upper limits, h(0)(95%) = 4.0 x 10(-25), 8.3 x 10(-25), and 3.0 x 10(-25) for electromagnetically restricted source orientation, unknown polarization, and circular polarization, respectively, are reported at 106 Hz. They are <= 10 times higher than the theoretical torque-balance limit at 106 Hz.
Abbott, B. P.; Abbott, R.; Abbott, D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Mikhailov, Eugeniy E.; Rew, H.; and Zhang, M., Search for gravitational waves from Scorpius X-1 in the first Advanced LIGO observing run with a hidden Markov model (2017). PHYSICAL REVIEW D, 95(12).