SRG/eROSITA view of X-ray reflection in the Central Molecular Zone: a
  snapshot in September-October 2019
  X-ray reflection off dense molecular clouds in the Galactic Centre region has
established itself as a powerful probe for the past activity record of the
supermassive black hole Sgr A* on a timescale of a few hundred years. Detailed
studies of the reflection signal from individual clouds allow us to estimate
parameters of the brightest flare(s) and explore properties of the dense gas
distribution inside and around them. On the other hand, wide area surveys
covering the full Central Molecular Zone (CMZ) are crucial to spot brightening
of the new clouds and long-term decay of the flux from the once bright ones.
Here we present and discuss the data obtained by the SRG/eROSITA telescope in
the course of its commissioning observations in late 2019 in regard to the
X-ray reflection off CMZ clouds located to the East of Sgr A*. We measure the
hard X-ray (4-8 keV) flux from the currently brightest (in reflected emission)
molecular complex Sgr A and derive upper limits for other molecular complexes.
We confirm that the Sgr A complex keeps being bright at the level of
$4\times10^{-13}\, {\rm erg\,s^{-1}\,cm^{-2}\,arcmin^{-2}}$, making it an
excellent candidate for the deep forthcoming high resolution imaging and
polarimetric observations. We also discuss distinct features of the reflected
emission from the clouds for which the primary illumination front has already
passed away and the signal is dominated by multiply scattered radiation.
