Impact of intrinsic polarisation of Sgr A* historical flares on
  (polarisation) properties of their X-ray echoes
  Reflection of X-ray emission on molecular clouds in the inner $\sim$ 100 pc
of our Galaxy reveals that, despite being extremely quiet at the moment, our
supermassive black hole Sgr A* should have experienced bright flares of X-ray
emission in the recent past. Thanks to the improving characterisation of the
reflection signal, we are able to infer parameters of the most recent flare(s)
(age, duration and luminosity) and relative line-of-sight disposition of the
brightest individual molecular complexes. We show that combining these data
with measurements of polarisation in the reflected X-ray continuum will not
only justify Sgr A* as the primary source but also allow deriving intrinsic
polarisation properties of the flare emission. This will help to identify
radiation mechanisms and underlying astrophysical phenomena behind them. For
the currently brightest reflecting molecular complex, Sgr A, the required level
of sensitivity might be already accessible with upcoming X-ray polarimeters.
