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On choosing the start time of binary black hole ringdowns

Bhagwat, Swetha and Okounkova, Maria and Ballmer, Stefan W. and Brown, Duncan A. and Giesler, Matthew and Scheel, Mark A. and Teukolsky, Saul A. (2018) On choosing the start time of binary black hole ringdowns. Physical Review D, 97 (10). Art. No. 104065. ISSN 2470-0010.

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The final stage of a binary black hole merger is ringdown, in which the system is described by a Kerr black hole with quasinormal mode perturbations. It is far from straightforward to identify the time at which the ringdown begins. Yet determining this time is important for precision tests of the general theory of relativity that compare an observed signal with quasinormal mode descriptions of the ringdown, such as tests of the no-hair theorem. We present an algorithmic method to analyze the choice of ringdown start time in the observed waveform. This method is based on determining how close the strong field is to a Kerr black hole (Kerrness). Using numerical relativity simulations, we characterize the Kerrness of the strong-field region close to the black hole using a set of local, gauge-invariant geometric and algebraic conditions that measure local isometry to Kerr. We produce a map that associates each time in the gravitational waveform with a value of each of these Kerrness measures; this map is produced by following outgoing null characteristics from the strong and near-field regions to the wave zone. We perform this analysis on a numerical relativity simulation with parameters consistent with GW150914—the first gravitational-wave detection. We find that the choice of ringdown start time of 3 ms after merger used in the GW150914 study [B. P. Abbott et al. (Virgo Collaboration and LIGO Scientific Collaboration), Phys. Rev. Lett. 116, 221101 (2016).] to test general relativity corresponds to a high dimensionless perturbation amplitude of ∼7.5×10^(-3) in the strong-field region. This suggests that in higher signal-to-noise detections, one would need to start analyzing the signal at a later time for studies that depend on the validity of black hole perturbation theory.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Brown, Duncan A.0000-0002-9180-5765
Giesler, Matthew0000-0003-2300-893X
Teukolsky, Saul A.0000-0001-9765-4526
Additional Information:© 2018 American Physical Society. Received 7 November 2017; published 30 May 2018. We would like to thank Alfonso García-Parrado Gómez-Lobo, Kevin Barkett, Mike Boyle, Yanbei Chen, Joshua Goldberg, Casey Handmer, Daniel Hemberger, Maximilliano Isi, Badri Krishnan, Nicholas Meyer, Harald Pfeiffer, Leo Stein and Vijay Varma for many valuable conversations. In particular, we would like to thank Mike Boyle, Casey Handmer, Harald Pfeiffer, and Leo Stein for careful reading of this manuscript. We would like to thank William East for helping to generate the QNM metrics, and Geoffrey Lovelace for supplying the BBH simulation data used in this study. This work was supported in part by the Sherman Fairchild Foundation, the Brinson Foundation, NSF Grants No. PHY-1404569 and No. AST-1333520 at Caltech, and NSF Grant No. PHY-1606654 at Cornell University and Grants No. PHY-1404395, No. PHY-1707954 and No. PHY-1352511 at Syracuse University. M. O. gratefully acknowledges the support of the Dominic Orr Graduate Fellowship at Caltech. We used SpEC (Spectral Einstein Code) to perform the simulations and analysis [81]. Computations were performed on the Zwicky and Wheeler clusters at Caltech, which are supported by the Sherman Fairchild Foundation and by NSF Grant No. PHY-0960291. The BBH simulation was performed on the ORCA cluster at California State University, Fullerton (CSUF), supported by CSUF, NSF Grant No. PHY-142987, and the Research Corporation for Science Advancement.
Group:Walter Burke Institute for Theoretical Physics, Astronomy Department
Funding AgencyGrant Number
Sherman Fairchild FoundationUNSPECIFIED
Brinson FoundationUNSPECIFIED
Dominic Orr Graduate FellowshipUNSPECIFIED
California State University, FullertonUNSPECIFIED
Research CorporationUNSPECIFIED
Issue or Number:10
Record Number:CaltechAUTHORS:20180530-091329126
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86703
Deposited By: Tony Diaz
Deposited On:30 May 2018 17:00
Last Modified:09 Mar 2020 13:18

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