Molecular clouds: X-ray mirrors of the Galactic nuclear activity
  We present the result of a study of the X-ray emission from the Galactic
Centre Molecular Clouds (MC), within 15 arcmin from Sgr A*. We use XMM-Newton
data spanning about 8 years. We observe an apparent super-luminal motion of a
light front illuminating a MC. This might be due to a source outside the MC
(such as Sgr A* or a bright and long outburst of a X-ray binary), while it can
not be due to low energy cosmic rays or a source located inside the cloud. We
also observe a decrease of the X-ray emission from G0.11-0.11, behaviour
similar to the one of Sgr B2. The line intensities, clouds dimensions, columns
densities and positions with respect to Sgr A*, are consistent with being
produced by the same Sgr A* flare. The required high luminosity (about 1.5
10^39 erg s-1) can hardly be produced by a binary system, while it is in
agreement with a flare of Sgr A* fading about 100 years ago.
