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An improved, "phase-relaxed" F-statistic for gravitational-wave data analysis

Cutler, Curt (2012) An improved, "phase-relaxed" F-statistic for gravitational-wave data analysis. Physical Review D, 86 (6). Art. No. 063012. ISSN 2470-0010.

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Rapidly rotating, slightly nonaxisymmetric neutron stars emit nearly periodic gravitational waves (GWs), quite possibly at levels detectable by ground-based GW interferometers. We refer to these sources as “GW pulsars.” For any given sky position and frequency evolution, the F-statistic is the maximum likelihood statistic for the detection of GW pulsars. However, in “all-sky” searches for previously unknown GW pulsars, it would be computationally intractable to calculate the (fully coherent) F-statistic at every point of (a suitably fine) grid covering the parameter space: the number of grid points is many orders of magnitude too large for that. Therefore, in practice some nonoptimal detection statistic is used for all-sky searches. Here we introduce a “phase-relaxed” F-statistic, which we denote F_(pr), for incoherently combining the results of fully coherent searches over short time intervals. We estimate (very roughly) that for realistic searches, our F_(pr) is ∼10–15% more sensitive than the “semicoherent” F-statistic that is currently used. Moreover, as a by-product of computing F_(pr), one obtains a rough determination of the time-evolving phase offset between one’s template and the true signal imbedded in the detector noise. Almost all the ingredients that go into calculating F_(pr) are already implemented in the LIGO Algorithm Library, so we expect that relatively little additional effort would be required to develop a search code that uses F_(pr).

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Additional Information:© 2012 American Physical Society. Received 25 April 2011; published 25 September 2012. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration. We gratefully acknowledge support from NSF Grant No. PHY-0601459. We also thank Michele Vallisneri, Holger Pletsch, Reinhard Prix, Badri Krishnan, and Bruce Allen for helpful discussions.
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Issue or Number:6
Classification Code:PACS: 95.55.Ym; 04.80.Nn; 95.75.Pq; 97.60.Gb
Record Number:CaltechAUTHORS:20121105-134352803
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Official Citation:Cutler, C. (2012). "An improved, “phase-relaxed” F-statistic for gravitational-wave data analysis." Physical Review D 86(6): 063012.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35284
Deposited By: Tony Diaz
Deposited On:08 Nov 2012 20:38
Last Modified:03 Oct 2019 04:26

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