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Two years of INTEGRAL monitoring of the Soft Gamma-Ray Repeater SGR 1806-20: from quiescence to frenzy

D. Gotz·S. Mereghetti·S. Molkov·K. Hurley·I. F. Mirabel·R. Sunyaev·G. Weidenspointner·S. Brandt·M. Del Santo·M. Feroci·E. Gogus·A. von Kienlin·M. van der Klis·C. Kouveliotou·N. Lund·G. Pizzichini·P. Ubertini·C. Winkler·P. M. Woods
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Abstract

SGR 1806-20 has been observed for more than 2 years with the INTEGRAL satellite. In this period the source went from a quiescent state into a very active one culminating in a giant flare on December 27 2004. Here we report on the properties of all the short bursts detected with INTEGRAL before the giant flare. We derive their number-intensity distribution and confirm the hardness-intensity correlation for the bursts found by Gotz et al. (2004a). Our sample includes a very bright outburst that occurred on October 5 2004, during which over one hundred bursts were emitted in 10 minutes, involving an energy release of 3 x 1E42 erg. We present a detailed analysis of it and discuss our results in the framework of the magnetar model.

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D. Gotz, S. Mereghetti, S. Molkov, K. Hurley, I. F. Mirabel, R. Sunyaev, G. Weidenspointner, S. Brandt, M. Del Santo, M. Feroci, E. Gogus, A. von Kienlin, M. van der Klis, C. Kouveliotou, N. Lund, G. Pizzichini, P. Ubertini, C. Winkler, P. M. Woods. 2005-08-29. Two years of INTEGRAL monitoring of the Soft Gamma-Ray Repeater SGR 1806-20: from quiescence to frenzy. https://doi.org/10.1051/0004-6361%3A20053648

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