Anomalous X-ray pulsars (AXPs) are a class of rare X-ray emitting pulsars whose energy source has been perplexing for some 20 years1,2,3. Unlike other X-ray emitting pulsars, AXPs cannot be powered by rotational energy or by accretion of matter from a binary companion star, hence the designation ‘anomalous’. Many of the rotational and radiative properties of the AXPs are strikingly similar to those of another class of exotic objects, the soft-γ-ray repeaters (SGRs). But the defining property of the SGRs—their low-energy-γ-ray and X-ray bursts—has not hitherto been observed for AXPs. Soft-γ-ray repeaters are thought to be ‘magnetars’, which are young neutron stars whose emission is powered by the decay of an ultra-high magnetic field4,5; the suggestion that AXPs might also be magnetars has been controversial6. Here we report two X-ray bursts, with properties similar to those of SGRs, from the direction of the anomalous X-ray pulsar 1E1048.1 - 5937. These events imply a close relationship (perhaps evolutionary) between AXPs and SGRs, with both being magnetars.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Fahlman, G. G. & Gregory, P. C. An X-ray pulsar in SNR G109.1–1.0. Nature 293, 202–204 (1981)
van Paradijs, J., Taam, R. E. & van den Heuvel, E. P. J. On the nature of the ‘anomalous’ 6-s X-ray pulsars. Astron. Astrophys. 299, L41–L44 (1995)
Mereghetti, S. & Stella, L. The very low mass X-ray binary pulsars: A new class of sources? Astrophys. J. 442, L17–L20 (1995)
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)
Kouveliotou, C. et al. An X-ray pulsar with a superstrong magnetic field in the soft γ-ray repeater SGR 1806–20. Nature 393, 235–237 (1998)
Chatterjee, P., Hernquist, L. & Narayan, R. An accretion model for anomalous X-ray pulsars. Astrophys. J. 534, 373–379 (2000)
Thompson, C. & Duncan, R. C. The soft gamma repeaters as very strongly magnetized neutron stars. II. Quiescent neutrino, x-ray, and Alfven wave emission. Astrophys. J. 473, 322–342 (1996)
Jahoda, K. et al. In-orbit performance and calibration of the Rossi X-ray Timing Explorer (RXTE) proportional counter array (PCA). Proc. SPIE 2808, 59–70 (1996)
Kaspi, V. M., Chakrabarty, D. & Steinberger, J. Phase-coherent timing of two anomalous X-ray pulsars. Astrophys. J. 525, L33–L36 (1999)
Kaspi, V. M., Lackey, J. R. & Chakrabarty, D. A glitch in an anomalous X-ray pulsar. Astrophys. J. 537, L31–L34 (2000)
Kaspi, V. M., Gavriil, F. P., Chakrabarty, D., Lackey, J. R. & Muno, M. P. Long-term RXTE monitoring of the anomalous X-ray pulsar 1E 1048.1-5973. Astrophys. J. 558, 253–262 (2001)
Gavriil, F. P. & Kaspi, V. M. Long-Term Rossi X-Ray Timing Explorer monitoring of anomalous X-ray pulsars. Astrophys. J. 567, 1067–1076 (2002)
Lewin, W. H. G., Van Paradijs, J. & Taam, R. E. X-ray Binaries (eds Lewin, W. H. G.van Paradijs, J. & van den Heuvel, E. P. J.) 175–232 (Cambridge Univ. Press, Cambridge, 1995)
Liu, Q. Z., van Paradijs, J. & van den Heuvel, E. P. J. A catalogue of low-mass X-ray binaries. Astron. Astrophys. 368, 1021–1054 (2001)
Heise, J., in't Zand, J., Kippen, M. & Woods, P. X-ray flashes and X-ray rich gamma-ray bursts. Mem. Soc. Astron. Ital. (in the press); preprint astro-ph0111246 at 〈http://xxx.lanl.gov〉 (2001).
Stern, B. E., Tikhomirova, Y., Kompaneets, D., Svensson, R. & Poutanen, J. An off-line scan of the BATSE daily records and a large uniform sample of gamma-ray bursts. Astrophys. J. 563, 80–94 (2001)
Fishman, G. J. et al. Overview of observations from BATSE on the Compton observatory. Astron. Astrophys. Suppl. 97, 17–20 (1993)
Göǧüs¸, E. et al. Temporal and spectral characteristics of short bursts from the soft gamma repeaters 1806-20 and 1900 + 14. Astrophys. J. 558, 228–236 (2001)
Ibrahim, A. I. et al. An unusual burst from soft gamma repeater SGR 1990 + 14: Comparisons with giant flares and implications for the magnetar model. Astrophys. J. 558, 237–252 (2001)
Strohmayer, T. E. & Ibrahim, A. I. Discovery of a 6.4 keV emission line in a burst from SGR 1900 + 14. Astrophys. J. 537, L111–L114 (2000)
Woods, P. M. et al. Evidence for a sudden magnetic field reconfiguration in soft gamma repeater 1900 + 14. Astrophys. J. 552, 748–755 (2001)
Pivovaroff, M., Kaspi, V. M. & Camilo, F. X-ray observations of the high magnetic field radio pulsar PSR J1814–1744. Astrophys. J. 535, 379–384 (2000)
Gotthelf, E. V., Vasisht, G. & Dotani, T. On the spin history of the X-ray pulsar in Kes 73: Further evidence for an ultramagnetized neutron star. Astrophys. J. 522, L49–L52 (1999)
Gaensler, B. M., Slane, P. O., Gotthelf, E. V. & Vasisht, G. Anomalous X-ray pulsars and soft gamma-ray repeaters in supernova remnants. Astrophys. J. 559, 963–972 (2001)
Tiengo, A., Göhler, E., Staubert, R. & Mereghetti, S. The anomalous X-ray pulsar 1E 1048.1-5937: Phase resolved spectroscopy with the XMM-Newton satellite. Astron. Astrophys. 383, 182–187 (2002)
Arnaud, K. A. Astronomical Data Analaysis Software and Systems V (eds Jacoby, G. & Barnes, J.) 17 (ASP, San Fransisco, 1996)
P.M.W. is affiliated to the Universities Space Research Association. We thank E. Kuulkers, K. Hurley, K. Jahoda, C. Kouveliotou, W. Lewin, M. Lyutikov, M. Muno, D. Psaltis, S. Ransom, M. Roberts, D. Smith and C. Thompson for discussions. This work was supported in part by a NASA LTSA grant, an NSERC research grant, and an NSF career award. V.M.K. is a Canada Research Chair and an Alfred P. Sloan Fellow. This work made use of data obtained through the High Energy Astrophysics Science Archive Research Center Online Service, provided by the NASA/Goddard Space Flight Center.
The authors declare that they have no competing financial interests.
About this article
Cite this article
Gavriil, F., Kaspi, V. & Woods, P. Magnetar-like X-ray bursts from an anomalous X-ray pulsar. Nature 419, 142–144 (2002) doi:10.1038/nature01011
Reports on Progress in Physics (2019)
The Astrophysical Journal (2019)
The Astrophysical Journal (2018)
Magnetar Giant Flares in Multipolar Magnetic Fields. III. Multipolar Magnetic Field Structure Variations
The Astrophysical Journal (2018)
Monthly Notices of the Royal Astronomical Society (2018)