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, A&A, 417, L45). 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 1042 erg. We present a detailed analysis of it and discuss our results in the framework of the magnetar model.
|Journal||Astronomy & Astrophysics|
|Publication status||Published - 2006|
- gamma rays : bursts
- stars : pulsars : general
- stars : pulsars : individual : SGR 1806-20
- gamma rays : observations