EROSITA Spectro-Imaging Analysis of the Abell 3408 Galaxy Cluster
  The X-ray telescope eROSITA onboard the newly launched SRG mission
serendipitously observed the galaxy cluster A3408 ($z=0.0420$) during the PV
observation of the AGN 1H0707-495. Despite its brightness and large extent, it
has not been observed by any modern X-ray observatory. A neighbouring cluster
in NW direction, A3407 ($z=0.0428$), appears to be close at least in projection
($\sim 1.7$ Mpc). This cluster pair could be in a pre- or post-merger state.
  We perform a detailed X-ray analysis of A3408. We construct particle
background subtracted and exposure corrected images and surface brightness
profiles in different sectors. The spectral analysis is performed out to
$1.4r_{500}$. Additionally, a temperature map is presented depicting the
distribution of the ICM temperature. Furthermore, we make use of data from the
RASS to estimate some bulk properties of A3408 and A3407, using the growth
curve analysis method and scaling relations.
  The imaging analysis shows a complex morphology of A3408 with a strong
elongation in SE-NW direction. This is quantified by comparing the surface
brightness profiles of the NW, SW, SE and NE directions, where the NW and SE
directions show a significantly higher surface brightness compared to the other
directions. We determine a gas temperature ${\rm k_B}T_{500}=(2.23\pm0.09)$
keV. The T-profile reveals a hot core within $2'$ of the emission peak, ${\rm
k_B}T=3.04^{+0.29}_{-0.25}$ keV. Employing a M-T relation, we obtain
$M_{500}=(9.27\pm0.75)\times 10^{13}M_{\odot}$ iteratively. The $r_{200}$ of
A3407 and A3408 are found to overlap in projection which makes ongoing
interactions plausible. The 2d T-map reveals higher temperatures in W than in E
direction.
  A3407 and A3408 are likely in a pre-merger state, affecting the ICM
properties, i.e., increased temperatures in the direction of A3407 indicate
adiabatic compression or shocks due to the interaction.
