Search for continuous gravitational waves from neutron stars in globular cluster NGC 6544
Source
Physical Review D
ISSN
24700010
Date Issued
2017-04-19
Author(s)
Abbott, B. P.
Abbott, R.
Abbott, T. D.
Abernathy, M. R.
Acernese, F.
Ackley, K.
Adams, C.
Adams, T.
Addesso, P.
Adhikari, R. X.
Adya, V. B.
Affeldt, C.
Agathos, M.
Agatsuma, K.
Aggarwal, N.
Aguiar, O. D.
Aiello, L.
Ain, A.
Allen, B.
Allocca, A.
Altin, P. A.
Anderson, S. B.
Anderson, W. G.
Arai, K.
Araya, M. C.
Arceneaux, C. C.
Areeda, J. S.
Arnaud, N.
Arun, K. G.
Ascenzi, S.
Ashton, G.
Ast, M.
Aston, S. M.
Astone, P.
Aufmuth, P.
Aulbert, C.
Babak, S.
Bacon, P.
Bader, M. K.M.
Baker, P. T.
Baldaccini, F.
Ballardin, G.
Ballmer, S. W.
Barayoga, J. C.
Barclay, S. E.
Barish, B. C.
Barker, D.
Barone, F.
Barr, B.
Barsotti, L.
Barsuglia, M.
Barta, D.
Bartlett, J.
Bartos, I.
Bassiri, R.
Basti, A.
Batch, J. C.
Baune, C.
Bavigadda, V.
Bazzan, M.
Bejger, M.
Bell, A. S.
Berger, B. K.
Bergmann, G.
Berry, C. P.L.
Bersanetti, D.
Bertolini, A.
Betzwieser, J.
Bhagwat, S.
Bhandare, R.
Bilenko, I. A.
Billingsley, G.
Birch, J.
Birney, R.
Biscans, S.
Bisht, A.
Bitossi, M.
Biwer, C.
Bizouard, M. A.
Blackburn, J. K.
Blair, C. D.
Blair, D. G.
Blair, R. M.
Bloemen, S.
Bock, O.
Boer, M.
Bogaert, G.
Bogan, C.
Bohe, A.
Bond, C.
Bondu, F.
Bonnand, R.
Boom, B. A.
Bork, R.
Boschi, V.
Bose, S.
Bouffanais, Y.
Bozzi, A.
Bradaschia, C.
Brady, P. R.
Abstract
We describe a directed search for continuous gravitational waves in data from the sixth initial LIGO science run. The target was the nearby globular cluster NGC 6544 at a distance of ≈2.7 kpc. The search covered a broad band of frequencies along with first and second frequency derivatives for a fixed sky position. The search coherently integrated data from the two LIGO interferometers over a time span of 9.2 days using the matched-filtering F-statistic. We found no gravitational-wave signals and set 95% confidence upper limits as stringent as 6.0×10-25 on intrinsic strain and 8.5×10-6 on fiducial ellipticity. These values beat the indirect limits from energy conservation for stars with characteristic spin-down ages older than 300 years and are within the range of theoretical predictions for possible neutron-star ellipticities. An important feature of this search was use of a barycentric resampling algorithm which substantially reduced computational cost; this method is used extensively in searches of Advanced LIGO and Virgo detector data.