Abstract
The massive flare of 27 December 2004 from the soft γ-ray repeater SGR 1806–20, a possible magnetar1,2,3, saturated almost all γ-ray detectors4,5,6,7, meaning that the profile of the pulse was poorly characterized. An accurate profile is essential to determine physically what was happening at the source. Here we report the unsaturated γ-ray profile for the first 600 ms of the flare, with a time resolution of 5.48 ms. The peak of the profile (of the order of 107 photons cm-2 s-1) was reached ∼50 ms after the onset of the flare, and was then followed by a gradual decrease with superposed oscillatory modulations possibly representing repeated energy injections with ∼60-ms intervals. The implied total energy is comparable to the stored magnetic energy in a magnetar (∼ 1047 erg) based on the dipole magnetic field intensity (∼ 1015 G), suggesting either that the energy release mechanism was extremely efficient or that the interior magnetic field is much stronger than the external dipole field2.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
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)
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)
Thompson, C. & Duncan, R. C. The giant flare of 1998 August 27 from SGR1900 + 14. II. Radiative mechanism and physical constraints on the source. Astrophys. J. 561, 980–1005 (2001)
Hurley, K. et al. An exceptionally bright flare from SGR1806 - 20 and the origins of short-duration γ-ray bursts. Nature doi:10.1038/nature03519 (this issue); preprint at http://arXiv.org/astro-ph/0502329 (2005)
Mazets, E. P. et al. The Konus-Wind and Helicon-Coronas-F detection of the giant γ-ray flare from the soft γ-ray repeater SGR 1806 - 20. Preprint at http://arXiv.org/astro-ph/0502541 (2005).
Mereghetti, S. et al. The first giant flare SGR 1806 - 20: observations with the INTEGRAL SPI anti-coincidence shield. Astrophys. J. Lett. (in the press); preprint at http://arXiv.org/astro-ph/0502577 (2005)
Palmer, D. M. et al. A giant γ-ray flare from the magnetar SGR 1806 - 20. Nature doi:10.1038/nature03525 (this issue); preprint at http://arXiv.org/astro-ph/0503030 (2005)
Barat, C. et al. Fine time structure in the 1979 March 5 gamma ray burst. Astron. Astrophys. 126, 400–402 (1983)
Mazets, E. P. et al. Activity of the soft gamma repeater SGR 1900 + 14 in 1998 from Konus-Wind observations: 2. The giant August 27 outburst. Astron. Lett. 25, 635–648 (1999)
Mukai, T. et al. The low energy particle (LEP) experiment onboard the Geotail satellite. J. Geomag. Geoelectr. 46, 669–692 (1994)
Kosugi, T. et al. The hard X-ray telescope (HXT) for the solar-A mission. Solar Phys. 136, 17–36 (1991)
Yoshimori, M. et al. The wide band spectrometer on the solar-A. Solar Phys. 136, 69–88 (1991)
Matsumoto, Y. et al. A statistical study of gamma-ray emitting solar flares observed with Yohkoh. Publ. Astron. Soc. Jpn. 57, 211–220 (2005)
Acknowledgements
We thank R. Yamazaki, K. Ioka, K. Shibata, T. Minoshima and K. Hurley for comments and discussions. This work was supported in part by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare that they have no competing financial interests.
Rights and permissions
About this article
Cite this article
Terasawa, T., Tanaka, Y., Takei, Y. et al. Repeated injections of energy in the first 600 ms of the giant flare of SGR 1806–20. Nature 434, 1110–1111 (2005). https://doi.org/10.1038/nature03573
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature03573
- Springer Nature Limited
This article is cited by
-
A bright γ-ray flare interpreted as a giant magnetar flare in NGC 253
Nature (2021)
-
Development of a Method for Determining the Search Window for Solar Flare Neutrinos
Solar Physics (2020)
-
Multi-Point Detection of the Elf Transient Caused by the Gamma Flare of December 27, 2004
Radiophysics and Quantum Electronics (2014)
-
Pulsars and Magnetars
Brazilian Journal of Physics (2013)
-
Impact of a gamma-ray burst on the Schumann resonance
Radiophysics and Quantum Electronics (2011)