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An X-ray pulsar with a superstrong magnetic field in the soft γ-ray repeater SGR1806 − 20

Nature volume 393, pages 235–237 (1998)Cite this article

Abstract

Soft γ-ray repeaters (SGRs) emit multiple, brief (∼0.1-s), intense outbursts of low-energy γ-rays. They are extremely rare1—three2,3,4 are known in our Galaxy and one5 in the Large Magellanic Cloud. Two SGRs are associated5,6,7 with young supernova remnants (SNRs), and therefore most probably with neutron stars, but it remains a puzzle why SGRs are so different from ‘normal’ radio pulsars. Here we report the discovery of pulsations in the persistent X-ray flux of SGR1806 − 20, with a period of 7.47 s and a spindown rate of 2.6 × 10−3 s yr−1. We argue that the spindown is due to magnetic dipole emission and find that the pulsar age and (dipolar) magnetic field strength are ∼1,500 years and 8× 1014 gauss, respectively. Our observations demonstrate the existence of ‘magnetars’, neutron stars with magnetic fields about 100 times stronger than those of radio pulsars, and support earlier suggestions8,9 that SGR bursts are caused by neutron-star ‘crustquakes’ produced by magnetic stresses. The ‘magnetar’ birth rate is about one per millennium—a substantial fraction of that of radio pulsars. Thus our results may explain why some SNRs have no radio pulsars.

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Figure 1: Fast-Fourier-transform power spectrum computed for the combined RXTE/PCA observations of 5/6, 7, 13 and 17 November 1996 in the 2–24. keV range.
Figure 2: Epoch folded pulse profiles of SGR1806 − 20.

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References

  1. Kouveliotou, C. et al. The rarity of soft γ-ray repeaters deduced from reactivation of SGR1806 − 20. Nature 368, 125–127 (1994).

    Article  ADS  Google Scholar 

  2. Norris, J. P., Hertz, P., Wood, K. S. & Kouveliotou, C. On the nature of Soft Gamma Repeaters. Astrophys. J. 366, 240–252 (1991).

    Article  ADS  CAS  Google Scholar 

  3. Hurley, K. in Gamma-Ray Bursts: 3rd Huntsville Symposium (eds Kouveliotou, C., Briggs, M. S. & Fishman, G. J.) 889–896 (AIP Conf. Proc. 384, Am. Inst. Phys., New York, (1995)).

    Google Scholar 

  4. Hurley, K. IAU Circ. No. 6743 ((1997)).

    Google Scholar 

  5. Cline, T. L. et al. Precise source location of the anomalous 1979 March 5 gamma-ray transient. Astrophys. J. 255, L45–L48 (1982).

    Article  ADS  Google Scholar 

  6. Murakami, T. et al. X-ray identification of the soft γ-ray repeater 1806-20. Nature 368, 127–129 (1994).

    Article  ADS  Google Scholar 

  7. Kulkarni, S. R. & Frail, D. A. Identification of a supernova remnant coincident with the soft γ-ray repeater SGR1806 − 20. Nature 365, 33–35 (1993).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  9. Thompson, C. & Duncan, R. The soft gamma repeaters as very strongly magnetized neutron stars. II. Quiescent neutrino, X-ray and Alfvén wave emission. Astrophys. J. 473, 322–342 (1996).

    Article  ADS  CAS  Google Scholar 

  10. Kouveliotou, C. et al. IAU Circ. No. 6501 ((1996)).

    Google Scholar 

  11. Kouveliotou, C. et al. IAU Circ. No. 6503 ((1996)).

    Google Scholar 

  12. Sonobe, T., Murakami, T., Kulkarni, S. R., Aoki, T. & Yoshida, A. Characteristics of the persistent emission of SGR1806 − 20. Astrophys. J. 436, L23–L25 (1994).

    Article  ADS  Google Scholar 

  13. Mazets, E. P., Golenetskii, S. V., Il'inskii, V. N., Aptekar, R. L. & Guryan, Yu. A. Observations of a flaring X-ray pulsar in Dorado. Nature 282, 587–589 (1979).

    Article  ADS  Google Scholar 

  14. Corbel, S. et al. The distance of the soft gamma repeater SGR1806 − 20. Astrophys. J. 478, 624–630 (1997).

    Article  ADS  CAS  Google Scholar 

  15. Kouveliotou, C. SGR activity and global characteristics. Astrophys. Space Sci. 231, 49–56 (1995).

    Article  ADS  Google Scholar 

  16. Kulkarni, S. R., Frail, D. A., Kassim, N. E., Murakami, T. & Vasisht, G. The radio nebula of the soft γ-ray repeater 1806 − 20. Nature 368, 129–131 (1994).

    Article  ADS  Google Scholar 

  17. Frail, D. A., Vasisht, G. & Kulkarni, S. R. The changing structure of the radio nebula around the soft gamma-ray repeater SGR1806 − 20. Astrophys. J. 480, L129–L132 (1997).

    Article  ADS  Google Scholar 

  18. Van Kerkwijk, M. H., Kulkarni, S. R., Matthews, K. & Neugebauer, G. Aluminous companion to SGR1806 − 20. Astrophys. J. 444, L33–L35 (1995).

    Article  ADS  CAS  Google Scholar 

  19. Michel, F. C. Theory of Neutron Star Magnetospheres (Univ. Chigaco Press, (1991)).

    Google Scholar 

  20. Thompson, C. & Blaes, O. Magnetohydrodynamics in the extreme relativistic limit. Phys. Rev. D 57(6), 3219–3234 (1998).

    Article  ADS  MathSciNet  Google Scholar 

  21. Paczýnski, B. GB790305 as a very strongly magnetized neutron star. Acta Astron. 42(3), 145–153 (1992).

    ADS  Google Scholar 

  22. Vasisht, G. & Gotthelf, E. V. The discovery of an anomalous X-ray pulsar in the supernova remnant Kes 73. Astrophys. J. 486, L129–L132 (1997).

    Article  ADS  Google Scholar 

  23. Mereghetti, S. & Stella, L. The very low mass X-ray binary pulsars: a new class of sources? Astrophys. J. 442, L17–L20 (1995).

    Article  ADS  Google Scholar 

  24. Van Paradijs, J., Taam, R. E. & van der Heuvel, E. P. J. On the nature of the ‘anomalous’ 6-s X-ray pulsars. Astron. Astrophys. 299, L41–L44 (1995).

    ADS  CAS  Google Scholar 

  25. Duncan, R. C. & Thompson, C. in High Velocity Neutron Stars and Gamma-Ray Bursts (eds Rothschild, R. E. & Lingenfelter, R. E.) 111–117 (AIP Conf. Proc. 366, Am. Inst. Phys., New York, (1995)).

    Google Scholar 

  26. Lyne, A. G. & Graham-Smith, F. Pulsar Astronomy (Cambridge Univ. Press, (1990)).

    Google Scholar 

  27. Narayan, R. & Ostriker, J. P. Pulsar populations and their evolution. Astrophys. J. 352, 222–246 (1990).

    Article  ADS  Google Scholar 

  28. Frail, D. A. in The Many Faces of Neutron Stars (eds Buccheri, R., van Paradijs, J. & Alpar, M. A.) (Kluwer Academic, in the press).

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Acknowledgements

We thank R. Duncan, C. Thompson and M. Finger for discussions.

Author information

Authors and Affiliations

  1. ES-84, Space Science Laboratory, NASA/Marshall Space Flight Center, Huntsville, 35812, Alabama, USA

    C. Kouveliotou, S. Dieters, G. J. Fishman & C. A. Meegan

  2. Universities Space Research Association, Alabama, 35899, USA

    C. Kouveliotou & T. Strohmayer

  3. University of Alabama in Huntsville, Alabama, 35899, USA

    S. Dieters & J. van Paradijs

  4. Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Greenbelt, 20771, Maryland, USA

    T. Strohmayer

  5. Astronomical Institute Anton Pannekoek,

    J. van Paradijs

  6. Space Sciences Laboratory, University of California, Berkeley, 94720-7450, California, USA

    K. Hurley

  7. Massachusetts Institute of Technology, MS 37-627, Cambridge, 02139, Massachusetts, USA

    J. Kommers

  8.  Rice University, Space Physics and Astronomy, 6100 South Main, MS 108, Houston, 77251-1892, Texas, USA

    I. Smith

  9. NRAO, VLA, 1003 Lopezville Road, Socorro, 87801, New Mexico, USA

    D. Frail

  10. ISAS, 3-1-1 Yoshinodai, Sagamihara, 229, Kanagawa, Japan

    T. Murakami

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  1. C. Kouveliotou
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  10. D. Frail
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Correspondence to C. Kouveliotou.

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Kouveliotou, C., Dieters, S., Strohmayer, T. et al. An X-ray pulsar with a superstrong magnetic field in the soft γ-ray repeater SGR1806 − 20. Nature 393, 235–237 (1998). https://doi.org/10.1038/30410

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