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A High Braking Index for a Pulsar

Archibald, R. F. and Gotthelf, E. V. and Ferdman, R. D. and Kaspi, V. M. and Guillot, S. and Harrison, F. A. and Keane, E. F. and Pivovaroff, M. J. and Stern, D. and Tendulkar, S. P. and Tomsick, J. A. (2016) A High Braking Index for a Pulsar. Astrophysical Journal Letters, 819 (1). Art. No. L16. ISSN 2041-8205. doi:10.3847/2041-8205/819/1/L16.

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We present a phase-coherent timing solution for PSR J1640–4631, a young 206 ms pulsar using X-ray timing observations taken with NuSTAR. Over this timing campaign, we have measured the braking index of PSR J1640–4631 to be n = 3.15 ± 0.03. Using a series of simulations, we argue that this unusually high braking index is not due to timing noise, but is intrinsic to the pulsar's spin-down. We cannot, however, rule out contamination due to an unseen glitch recovery, although the recovery timescale would have to be longer than most yet observed. If this braking index is eventually proven to be stable, it demonstrates that pulsar braking indices greater than three are allowed in nature; hence, other physical mechanisms such as mass or magnetic quadrupoles are important in pulsar spin-down. We also present a 3σ upper limit on the pulsed flux at 1.4 GHz of 0.018 mJy.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Archibald, R. F.0000-0002-4017-8837
Gotthelf, E. V.0000-0003-3847-3957
Kaspi, V. M.0000-0001-9345-0307
Guillot, S.0000-0002-6449-106X
Harrison, F. A.0000-0003-2992-8024
Keane, E. F.0000-0002-4553-655X
Stern, D.0000-0003-2686-9241
Tendulkar, S. P.0000-0003-2548-2926
Tomsick, J. A.0000-0001-5506-9855
Additional Information: © 2016 American Astronomical Society. Received 2015 December 16; accepted 2016 February 17; published 2016 March 1. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. Parkes radio telescope is part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. We also thank an anonymous referee for helpful comments that improved the manuscript. R.F.A. acknowledges support from an NSERC Alexander Graham Bell Canada Graduate Scholarship. E.V.G. received support from the National Aeronautics and Space Administration through Chandra Award Number GO5-16061X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. V.M.K. receives support from an NSERC Discovery Grant and Accelerator Supplement, Centre de Recherche en Astrophysique du Quebéc, an R. Howard Webster Foundation Fellowship from the Canadian Institute for Advanced Study, the Canada Research Chairs Program, and the Lorne Trottier Chair in Astrophysics and Cosmology. Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Commonwealth of AustraliaUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Centre de Recherche en Astrophysique du QuébecUNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
Canada Research Chairs ProgramUNSPECIFIED
Lorne Trottier Chair in Astrophysics and CosmologyUNSPECIFIED
Department of Energy (DOE)DE-AC52-07NA27344
R. Howard Webster FoundationUNSPECIFIED
Subject Keywords:pulsars: general; pulsars: individual (PSR J1640–4631) ; stars: neutron
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-18
Issue or Number:1
Record Number:CaltechAUTHORS:20160317-120714436
Persistent URL:
Official Citation:R. F. Archibald et al 2016 ApJ 819 L16
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65438
Deposited By: Ruth Sustaita
Deposited On:17 Mar 2016 21:19
Last Modified:10 Nov 2021 23:45

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