Abbott, B. P.Davies, G. S.LIGO Scientific Collaboration and Virgo Collaboration2017-07-182017-07-182017-06-27Abbott, BP., et al., (LIGO Scientific Collaboration and Virgo Collaboration). (2017) Search for gravitational waves from Scorpius X-1 in the first Advanced LIGO observing run with a hidden Markov model. Physical Review D, Volume 95, Issue 12, June 2017, Article number 122003http://doi.org/10.1103/PhysRevD.95.122003http://dspace.lib.cranfield.ac.uk/handle/1826/12205Article is made available in accordance with the publisher's policy. Please refer to the publisher's site for terms of use.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, h95% 0 ¼ 4.0 × 10−25, 8.3 × 10−25, and 3.0 × 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.enArticle1220039512