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Very fast optical flaring from a possible new Galactic magnetar


Highly luminous rapid flares are characteristic of processes around compact objects like white dwarfs, neutron stars and black holes. In the high-energy regime of X-rays and γ-rays, outbursts with variabilities on timescales of seconds or less are routinely observed, for example in γ-ray bursts1 or soft γ-ray repeaters2. At optical wavelengths, flaring activity on such timescales has not been observed, other than from the prompt phase of one exceptional γ-ray burst3. This is mostly due to the fact that outbursts with strong, fast flaring are usually discovered in the high-energy regime; most optical follow-up observations of such transients use instruments with integration times exceeding tens of seconds, which are therefore unable to resolve fast variability. Here we show the observation of extremely bright and rapid optical flaring in the Galactic transient4,5,6,7 SWIFT J195509.6+261406. Our optical light curves are phenomenologically similar to high-energy light curves of soft γ-ray repeaters and anomalous X-ray pulsars8, which are thought to be neutron stars with extremely high magnetic fields (magnetars). This suggests that similar processes are in operation, but with strong emission in the optical, unlike in the case of other known magnetars.

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Figure 1: Overview of overall optical high-time-resolution light curves of SWIFT J1955.
Figure 2: Detailed light curves of the two most prominent flares of the epoch 2007 June 11 of Fig. 1 .
Figure 3: Power spectral densities of the two prominent flares shown in Fig. 2 .


  1. Mészáros, P. Gamma ray bursts. Rep. Prog. Phys. 69, 2259–2321 (2006)

    Article  ADS  Google Scholar 

  2. Kouveliotou, C. in From X-Ray Binaries to Gamma-Ray Bursts (eds van den Heuvel, E. P., Kaper, L., Rol, E. & Wijers, R. A. M. J.) 413–423 (Astronomical Society of the Pacific, 2003)

    Google Scholar 

  3. Racusin, J. L. et al. Broadband observations of the naked-eye γ-ray burst GRB 080319B. Nature 455, 183–188 (2008)

    Article  ADS  CAS  Google Scholar 

  4. Stefanescu, A. et al. GRB 070610: OPTIMA-Burst high-time-resolution optical observations. GCN Circ. 6492, (2007)

  5. de Ugarte Postigo, A., Castro-Tirado, A. J. & Aceituno, F. GRB 070610: Optical observations from OSN. GCN Circ. 6501, (2007)

  6. Kann, D. A. et al. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient? GCN Circ. 6505, (2007)

  7. Kasliwal, M. M. et al. GRB070610: A curious Galactic transient. Astrophys. J. 678, 1127–1135 (2008)

    Article  ADS  CAS  Google Scholar 

  8. Kaspi, V. Recent progress on anomalous X-ray pulsars. Astrophys. Space Sci. 308, 1–11 (2007)

    Article  ADS  Google Scholar 

  9. Pagani, C. et al. GRB 070610: Swift detection of a burst. GCN Circ. 6489, (2007)

  10. Barthelmy, S. D. et al. The Burst Alert Telescope (BAT) on the SWIFT Midex Mission. Space Sci. Rev. 120, 143–164 (2005)

    Article  ADS  Google Scholar 

  11. Gehrels, N. et al. The Swift Gamma-Ray Burst Mission. Astrophys. J. 611, 1005–1020 (2005)

    Article  ADS  Google Scholar 

  12. Burrows, D. N. et al. The Swift X-Ray Telescope. Space Sci. Rev. 120, 165–195 (2005)

    Article  ADS  Google Scholar 

  13. Weisskopf, M. C. et al. An overview of the performance and scientific results from the Chandra X-Ray Observatory. Publ. Astron. Soc. Pacif. 114, 1–24 (2002)

    Article  ADS  Google Scholar 

  14. Stefanescu, A. et al. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity. GCN Circ. 6508, (2007)

  15. Markwardt, C. B. et al. SWIFT J195509.6+261406 / GRB 070610: A potential Galactic transient. Astronom. Telegr. 1102, (2007)

  16. Kanbach, G. et al. in High Time Resolution Astrophysics (eds Phelan, D., Ryan, O. & Shearer, A.) 153–169 (Springer, 2008)

    Google Scholar 

  17. Hurley, K. et al. Reactivation and precise interplanetary network localization of the soft gamma repeater SGR 1900+14. Astrophys. J. 510, L107–L109 (1999)

    Article  ADS  Google Scholar 

  18. Castro-Tirado, A. J. et al. Flares from a candidate Galactic magnetar suggest a missing link to dim isolated neutron stars. Nature 10.1038/nature07328 (this issue)

  19. Kaspi, V. 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)

    Article  ADS  Google Scholar 

  20. Durant, M. & van Kerkwijk, M. H. Multiwavelength variability of the magnetar 4U 0142+61. Astrophys. J. 652, 576–583 (2006)

    Article  ADS  CAS  Google Scholar 

  21. Kosugi, G., Ogasawara, R. & Terada, H. A variable infrared counterpart to the soft gamma-ray repeater SGR 1806–20. Astrophys. J. 623, L125–L128 (2005)

    Article  ADS  CAS  Google Scholar 

  22. Testa, V. et al. Adaptive optics, near-infrared observations of magnetars. Astron. Astrophys. 482, 607–615 (2008)

    Article  ADS  CAS  Google Scholar 

  23. Beloborodov, A. M. & Thompson, C. Corona of magnetars. Astrophys. J. 657, 967–993 (2007)

    Article  ADS  CAS  Google Scholar 

  24. Uemura, M. et al. Outburst of a black hole X-ray binary V4641 Sgr in 2004 July. Info. Bull. Var. Stars 5626, 1 (2005)

    ADS  Google Scholar 

  25. Uemura, M. et al. Optical observation of the 2003 outburst of a black hole X-Ray binary, V4641 Sagittarii. Publ. Astron. Soc. Jpn 56, 823–829 (2004)

    Article  ADS  CAS  Google Scholar 

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We thank the Skinakas Observatory for their support and allocation of telescope time, and acknowledge the allocation of Chandra DDT time. We thank F. Schrey, T. Kougentakis and G. Paterakis for technical support, A. de Ugarte Postigo for access to private data taken simultaneous to some of our observations and A. Castro-Tirado for discussions. Skinakas Observatory is a collaborative project of the University of Crete, the Foundation for Research and Technology - Hellas, and the Max-Planck-Institute for Extraterrestrial Physics. A. Stefanescu acknowledges support from OPTICON. A. Słowikowska acknowledges support of the European Union through a Marie Curie Transfer of Knowledge Fellowship within the Sixth Framework Programme. S.McB. acknowledges the support of the European Union through a Marie Curie Intra-European Fellowship within the Sixth Framework Programme. G.S. is supported through DLR.

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Stefanescu, A., Kanbach, G., Słowikowska, A. et al. Very fast optical flaring from a possible new Galactic magnetar. Nature 455, 503–505 (2008).

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