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An anti-glitch in a magnetar



Magnetars are neutron stars with X-ray and soft γ-ray outbursts thought to be powered by intense internal magnetic fields1. Like conventional neutron stars in the form of radio pulsars, magnetars exhibit ‘glitches’ during which angular momentum is believed to be transferred between the solid outer crust and the superfluid component of the inner crust2,3,4. The several hundred observed glitches in radio pulsars5,6 and magnetars7 have involved a sudden spin-up (increase in the angular velocity) of the star, presumably because the interior superfluid was rotating faster than the crust. Here we report X-ray timing observations of the magnetar 1E 2259+586 (ref. 8), which exhibited a clear ‘anti-glitch’—a sudden spin-down. We show that this event, like some previous magnetar spin-up glitches9, was accompanied by multiple X-ray radiative changes and a significant spin-down rate change. Such behaviour is not predicted by models of neutron star spin-down and, if of internal origin, is suggestive of differential rotation in the magnetar, supporting the need for a rethinking of glitch theory for all neutron stars10,11.

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Figure 1: Timing and flux properties of 1E 2259+586 around the 2012 event.


  1. 1

    Thompson, C. & Duncan, R. C. The soft gamma repeaters as very strongly magnetized neutron stars—I. Radiative mechanism for outbursts. Mon. Not. R. Astron. Soc. 275, 255–300 (1995)

    ADS  Article  Google Scholar 

  2. 2

    Anderson, P. W. & Itoh, N. Pulsar glitches and restlessness as a hard superfluidity phenomenon. Nature 256, 25–27 (1975)

    ADS  Article  Google Scholar 

  3. 3

    Pines, D. & Alpar, M. A. Superfluidity in neutron stars. Nature 316, 27–32 (1985)

    ADS  Article  Google Scholar 

  4. 4

    Link, B., Epstein, R. I. & van Riper, K. A. Pulsar glitches as probes of neutron star interiors. Nature 359, 616–618 (1992)

    ADS  Article  Google Scholar 

  5. 5

    Espinoza, C. M., Lyne, A. G., Stappers, B. W. & Kramer, M. A study of 315 glitches in the rotation of 102 pulsars. Mon. Not. R. Astron. Soc. 414, 1679–1704 (2011)

    ADS  Article  Google Scholar 

  6. 6

    Yu, M. et al. Detection of 107 glitches in 36 southern pulsars. Mon. Not. R. Astron. Soc. 429, 688–724 (2013)

    ADS  Article  Google Scholar 

  7. 7

    Dib, R., Kaspi, V. M. & Gavriil, F. P. Glitches in anomalous X-ray pulsars. Astrophys. J. 673, 1044–1061 (2008)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Fahlman, G. G. & Gregory, P. C. An X-ray pulsar in SNR G109.1–1.0. Nature 293, 202–204 (1981)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Kaspi, V. M. et al. A major soft gamma repeater-like outburst and rotation glitch in the no-longer-so-anomalous X-ray pulsar 1E 2259+586. Astrophys. J. 588, L93–L96 (2003)

    ADS  Article  Google Scholar 

  10. 10

    Ruderman, M., Zhu, T. & Chen, K. Neutron star magnetic field evolution, crust movement, and glitches. Astrophys. J. 492, 267 (1998)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Andersson, N., Glampedakis, K., Ho, W. C. G. & Espinoza, C. M. Pulsar glitches: the crust is not enough. Phys. Rev. Lett. 109, 241103 (2012)

    ADS  CAS  Article  Google Scholar 

  12. 12

    Içdem, B., Baykal, A. & Inam, S. Ç. RXTE timing analysis of the anomalous X-ray pulsar 1E 2259+586. Mon. Not. R. Astron. Soc. 419, 3109–3114 (2012)

    ADS  Article  Google Scholar 

  13. 13

    Gavriil, F. P., Kaspi, V. M. & Woods, P. M. A comprehensive study of the X-ray bursts from the magnetar candidate 1E 2259+586. Astrophys. J. 607, 959–969 (2004)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Burrows, D. et al. The Swift X-ray telescope. Space Sci. Rev. 120, 165–195 (2005)

    ADS  Article  Google Scholar 

  15. 15

    Hobbs, G. B., Edwards, R. T. & Manchester, R. N. TEMPO2, a new pulsar-timing package—I. An overview. Mon. Not. R. Astron. Soc. 369, 655–672 (2006)

    ADS  Article  Google Scholar 

  16. 16

    Foley, S., Kouveliotou, C., Kaneko, Y. & Collazzi, A. Fermi/GBM detection of a burst from the magnetar 1E 2259+5. GRB Coord. Netw. 13280, 1 (2012)

    Google Scholar 

  17. 17

    Woods, P. M. et al. Variable spin-down in the soft gamma repeater SGR 1900+14 and correlations with burst activity. Astrophys. J. 524, L55–L58 (1999)

    ADS  CAS  Article  Google Scholar 

  18. 18

    Gavriil, F. P., Dib, R. & Kaspi, V. M. The 2006–2007 active phase of anomalous X-ray pulsar 4U 0142+61: radiative and timing changes, bursts, and burst spectral features. Astrophys. J. 736, 138 (2011)

    ADS  Article  Google Scholar 

  19. 19

    Livingstone, M. A., Kaspi, V. M. & Gavriil, F. P. Timing behavior of the magnetically active rotation-powered pulsar in the supernova remnant Kesteven 75. Astrophys. J. 710, 1710–1717 (2010)

    ADS  Article  Google Scholar 

  20. 20

    Thompson, C. et al. Physical mechanisms for the variable spin-down and light curve of SGR 1900+14. Astrophys. J. 543, 340–350 (2000)

    ADS  CAS  Article  Google Scholar 

  21. 21

    International Consortium Of Scientists. CASA: Common Astronomy Software Applications. Astrophysics Source Code Library 7013 (2011) ;

  22. 22

    Granot, J. et al. Diagnosing the outflow from the SGR 1806–20 giant flare with radio observations. Astrophys. J. 638, 391–396 (2006)

    ADS  CAS  Article  Google Scholar 

  23. 23

    Thompson, C. & Blaes, O. Magnetohydrodynamics in the extreme relativistic limit. Phys. Rev. D 57, 3219–3234 (1998)

    ADS  MathSciNet  CAS  Article  Google Scholar 

  24. 24

    Harding, A. K., Contopoulos, I. & Kazanas, D. Magnetar spin-down. Astrophys. J. 525, L125–L128 (1999)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Beloborodov, A. M. Untwisting magnetospheres of neutron stars. Astrophys. J. 703, 1044–1060 (2009)

    ADS  Article  Google Scholar 

  26. 26

    Parfrey, K., Beloborodov, A. M. & Hui, L. Twisting, reconnecting magnetospheres and magnetar spindown. Astrophys. J. 754, L12 (2012)

    ADS  Article  Google Scholar 

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V.M.K. acknowledges support from the Natural Sciences and Engineering Research Council of Canada Discovery Grant and the John C. Polanyi Award, from the Canadian Institute for Advanced Research, from Fonds de Recherche Nature et Technologies Québec, from the Canada Research Chairs Program, and from the Lorne Trottier Chair in Astrophysics and Cosmology. D.T. was supported by the Lorne Trottier Chair in Astrophysics and Cosmology and the Canadian Institute for Advanced Research. K.N.G. was supported by the Centre de Recherche en Astrophysique du Québec. We thank H. Medlin and J. Gelfand for help with the EVLA observation. We thank D. Eichler, B. Link, M. Lyutikov and C. Thompson for useful discussions. We acknowledge the use of public data from the Swift data archive.

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R.F.A. performed the data analysis and wrote portions of the analysis software. V.M.K. designed the study, was the project leader for the Swift data, proposed for the Chandra data and assisted with the interpretation of the data analysis and the theoretical implications. C.Y.N. proposed for the VLA data and reduced them and the Chandra data. K.N.G. and D.T. assisted with the theoretical implications. P.S. wrote significant portions of the Swift analysis software. A.P.B., N.G. and J.A.K. assisted with Swift observations and data analysis. R.F.A. wrote the paper with guidance from V.M.K. and with significant input from all co-authors.

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Correspondence to V. M. Kaspi.

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The authors declare no competing financial interests.

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Supplementary Information

This file contains Supplementary Text and Data, which includes 1) Observations and 2) a Supplementary Discussion, Supplementary Figure 1 and additional references. (PDF 251 kb)

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Archibald, R., Kaspi, V., Ng, CY. et al. An anti-glitch in a magnetar. Nature 497, 591–593 (2013).

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