Sgr D and Sgr E: two distant witnesses of Sgr A*.s past activity

We propose two XMM observations of 100 ks each to capture the echo of Sgr A*.spast flares before they leave the central molecular zone. These observations ofthe distant molecular clouds Sgr D and E with XMM.s large effective area arerequired to extend our knowledge of Sgr A*.s past light curve further back intime. It will permit us to extend our global study of the GC Xray diffuseemission, which concludes that two short events happening few hundred years agoand currently propagating through the ISM are sufficient to explain all thevariations we have detected. The objective of this project is to fully identifyan older outburst from Sgr A*. This will better constrain the frequency of thesepast events and bring us closer to establishing their physical origin. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]