Studying the merging cluster Abell 3266 with eROSITA
  Abell 3266 is one of the X-ray brightest galaxy clusters in the sky and is a
well-known merging system. Using the ability of the eROSITA telescope onboard
SRG (Spectrum R\"ontgen Gamma) to observe a wide field with a single pointing,
we analysed a new observation of the cluster out to a radius of R_200. The
X-ray images highlight sub-structures present in the cluster, including the
north-east--south-west merger seen in previous ASCA, Chandra, and XMM-Newton
data, a merging group towards the north-west, and filamentary structures
between the core and one or more groups towards the west. We compute spatially
resolved spectroscopic maps of the thermodynamic properties of the cluster,
including the metallicity. The merging subclusters are seen as low entropy
material within the cluster. The filamentary structures could be the rims of a
powerful outburst of an active galactic nucleus, or most likely material
stripped from the western group(s) as they passed through the cluster core.
Seen in two directions is a pressure jump at a radius of 1.1 Mpc, which is
consistent with a shock with a Mach number of ~1.5-1.7. The eROSITA data
confirm that the cluster is not a simple merging system, but it is made up of
several subclusters which are merging or will shortly merge. We computed a
hydrostatic mass from the eROSITA data, finding good agreement with a previous
XMM-Newton result. With this pointing we detect several extended sources, where
we find secure associations between z=0.36-1.0 for seven of them, that is
background galaxy groups and clusters, highlighting the power of eROSITA to
find such systems.
