ESA Science & Technology - Two years of INTEGRAL monitoring of the Soft Gamma-Ray repeater SGR 1806-20, from quiescence to frenzy

Publication date: 15 December 2005

Authors: Götz, D., et al.

Journal: Astronomy & Astrophysics
Year: 2006

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 Götz 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 3x10⁴² erg. We present a detailed analysis of it and discuss our results in the framework of the magnetar model.