TY - JOUR
T1 - Directed search for gravitational waves from Scorpius X-1 with initial LIGO data
AU - Aylott, Benjamin
AU - Berry, Christopher
AU - Bond, Charlotte
AU - Brown, Daniel
AU - Del Pozzo, Walter
AU - Farr, Will
AU - Freise, Andreas
AU - Haster, Carl-Johan
AU - Mandel, Ilya
AU - Miao, Haixing
AU - Middleton, Hannah
AU - Sidery, Trevor
AU - Stevenson, Simon
AU - Vecchio, Alberto
AU - Veitch, John
AU - Vousden, Will
AU - Wang, Haoyu
AU - Wang, Mengyao
AU - LIGO Scientific Collaboration
AU - Virgo Collaboration
PY - 2015/3/26
Y1 - 2015/3/26
N2 - We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50–550 Hz, and performs an incoherent sum of coherent F-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3×10−24 and 8×10−25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof-of-principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ∼1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector.
AB - We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50–550 Hz, and performs an incoherent sum of coherent F-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3×10−24 and 8×10−25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof-of-principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ∼1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector.
U2 - 10.1103/physrevd.91.062008
DO - 10.1103/physrevd.91.062008
M3 - Article
SN - 1550-7998
VL - 91
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
M1 - 062008
ER -