A High Braking Index for a Pulsar
Abstract
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.
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.Attached Files
Published - Archibald_2016pL16.pdf
Submitted - 1603.00305v1.pdf
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Additional details
- Eprint ID
- 65438
- Resolver ID
- CaltechAUTHORS:20160317-120714436
- NASA/JPL/Caltech
- Commonwealth of Australia
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- GO5-16061X
- NASA
- NAS8-03060
- NASA
- Centre de Recherche en Astrophysique du Québec
- Canadian Institute for Advanced Research (CIFAR)
- Canada Research Chairs Program
- Lorne Trottier Chair in Astrophysics and Cosmology
- DE-AC52-07NA27344
- Department of Energy (DOE)
- R. Howard Webster Foundation
- Created
-
2016-03-17Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- NuSTAR, Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 2016-18