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The NANOGrav 11-year Data Set: Pulse Profile Variability

Brook, P. R. and Lazio, T. J. W. (2018) The NANOGrav 11-year Data Set: Pulse Profile Variability. Astrophysical Journal, 868 (2). Art. No. 122. ISSN 1538-4357.

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Access to 50 years of data has led to the discovery of pulsar emission and rotation variability on timescales of months and years. Most of this long-term variability has been seen in long-period pulsars, with relatively little focus on recycled millisecond pulsars. We have analyzed a 38-pulsar subset of the 45 millisecond pulsars in the NANOGrav 11-year data set, in order to review their pulse profile stability. The most variability, on any timescale, is seen in PSRs J1713+0747, B1937+21, and J2145−0750. The strongest evidence for long-timescale pulse profile changes is seen in PSRs B1937+21 and J1643−1224. We have focused our analyses on these four pulsars in an attempt to elucidate the causes of their profile variability. Effects of scintillation seem to be responsible for the profile modifications of PSR J2145−0750. We see evidence that imperfect polarization calibration contributes to the profile variability of PSRs J1713+0747 and B1937+21, along with radio frequency interference around 2 GHz, but find that propagation effects also have an influence. The changes seen in PSR J1643−1224 have been reported previously, yet elude explanation beyond their astrophysical nature. Regardless of cause, unmodeled pulse profile changes are detrimental to the accuracy of pulsar timing and must be incorporated into the timing models where possible.

Item Type:Article
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URLURL TypeDescription Paper
Brook, P. R.0000-0003-3053-6538
Lazio, T. J. W.0000-0002-3873-5497
Additional Information:© 2018. The American Astronomical Society. Received 2018 April 21; revised 2018 September 17; accepted 2018 October 17; published 2018 November 30. The NANOGrav project is supported by NSF Physics Frontiers Center award PHYS-1430284. P.R.B. is supported by Track I award OIA-1458952. The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Arecibo Observatory is operated by SRI International under a cooperative agreement with the NSF (AST-11000968), and in alliance with the Ana G. Méndez-Universidad Metropolitana and the Universities Space Research Association. Pulsar research at the University of British Columbia is supported by an NSERC Discovery Grant and by the Canadian Institute for Advanced Research. J.A.E. was partially supported by NASA through Einstein Fellowship grant PF4-150120. W.W.Z. is supported by the CAS Pioneer Hundred Talents Program and the Strategic Priority Research Program of the Chinese Academy of Sciences grant No. XDB23000000. Portions of this work performed at NRL were supported by the Chief of Naval Research.
Funding AgencyGrant Number
Ana G. Méndez-Universidad MetropolitanaUNSPECIFIED
Universities Space Research AssociationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
NASA Einstein FellowshipPF4-150120
China 1000-Young Talents PlanUNSPECIFIED
Chinese Academy of SciencesXDB23000000
Chief of Naval ResearchUNSPECIFIED
Subject Keywords: ISM: general; pulsars: general; pulsars: individual (J1643−1224, J1713+0747, B1937+21, J2145−0750) ; stars: neutron
Issue or Number:2
Record Number:CaltechAUTHORS:20181130-095502737
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Official Citation:P. R. Brook et al 2018 ApJ 868 122
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91359
Deposited By: George Porter
Deposited On:30 Nov 2018 18:24
Last Modified:09 Mar 2020 13:18

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