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Tracking the precession of compact binaries from their gravitational-wave signal

Schmidt, Patricia and Hannam, Mark and Husa, Sascha and Ajith, P. (2011) Tracking the precession of compact binaries from their gravitational-wave signal. Physical Review D, 84 (2). Art. No. 024046. ISSN 2470-0010.

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We present a simple method to track the precession of a black-hole-binary system during the inspiral, using only information from the gravitational-wave (GW) signal. Our method consists of locating the frame from which the magnitudes of the (ℓ=2, |m|=2) modes are maximized, which we denote the “quadrupole-aligned” frame. We demonstrate the efficacy of this method when applied to waveforms from numerical simulations. In the test case of an equal-mass nonspinning binary, our method locates the direction of the orbital angular momentum to within (Δθ,Δφ)=(0.05°,0.2°). We then apply the method to a q=M_2/M_1=3 binary that exhibits significant precession. In general, a spinning binary’s orbital angular momentum L is not orthogonal to the orbital plane. Evidence that our method locates the direction of L rather than the normal of the orbital plane is provided by comparison with post-Newtonian results. Also, we observe that it accurately reproduces similar higher-mode amplitudes to a comparable non-precessing binary, and that the frequency of the (ℓ=2, |m|=2) modes is consistent with the “total frequency” of the binary’s motion. The simple form of the quadrupole-aligned waveform may be useful in attempts to analytically model the inspiral-merger-ringdown signal of precessing binaries, and in standardizing the representation of waveforms for studies of accuracy and consistency of source modelling efforts, both numerical and analytical.

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Ajith, P.0000-0001-7519-2439
Additional Information:© 2011 American Physical Society. Received 17 December 2010; published 29 July 2011. We thank Jennifer Seiler for letting us know about her ongoing work on a similar algorithm, and B. S. Sathyaprakash, Stephen Fairhurst, Michael Pürrer, and Denis Pollney for discussions. P. Schmidt is a recipient of a DOC-fFORTE-fellowship of the Austrian Academy of Sciences and was also partially supported by FWF grant P22498. M. Hannam was supported by FWF grant M1178 and Science and Technology Facilities Council grants ST/H008438/1 and ST/I001085/1. S. Husa was supported by grant FPA-2007-60220 from the Spanish Ministry of Science and the Spanish MICINNs Consolider-Ingenio 2010 Programme under grant MultiDark CSD2009-00064, and thanks Cardiff University for hospitality. P. Ajith was supported in part by NSF grants PHY-0653653 and PHY-0601459, and the David and Barbara Groce Fund at Caltech. BAM simulations were carried out at LRZ Munich, ICHEC Dublin, the Vienna Scientific Cluster (VSC), and at MareNostrum at Barcelona Supercomputing Center—Centro Nacional de Supercomputaciόn (Spanish National Supercomputing Center).
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/H008438/1
Science and Technology Facilities Council (STFC)ST/I001085/1
Spanish Ministry of Science and the Spanish MICINNsFPA-2007-60220
Spanish Ministry of Science and the Spanish MICINNsCSD2009-00064
Caltech David and Barbara Groce Startup FundUNSPECIFIED
Issue or Number:2
Classification Code:PACS: 04.25.dg, 04.25.Nx, 04.30.Db, 04.70.Bw
Record Number:CaltechAUTHORS:20110816-140615307
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Official Citation:Tracking the precession of compact binaries from their gravitational-wave signal Patricia Schmidt, Mark Hannam, Sascha Husa, and P. Ajith Published 29 July 2011 (12 pages) 024046
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:24895
Deposited By: Ruth Sustaita
Deposited On:16 Aug 2011 22:18
Last Modified:09 Mar 2020 13:18

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