Long term XMM-Newton and INTEGRAL monitoring of SGR1806-20 after the Giant Flare

In December 2004 SGR 180620 emitted the most powerful giant flare ever observedfrom a Soft Gammaray Repeater. This probably involved a large scalerearrangement of the magnetosphere leading to observable variations in theproperties of its persistent Xray emission. Comparison of the preflareobservations with those obtained after this event supports the model of amagnetar with a twisted magnetosphere. We propose to continue our XMMNewtonmonitoring of SGR 180620, complemented by INTEGRAL observations, in order tostudy the long term effects of the Giant Flare and how the source evolves towardquiescence after this onceinalifetime event. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]