Passive spirals and shock influenced star formation in the merging
  cluster A3376
  We present a detailed analysis of star formation properties of galaxies in a
nearby ($z\sim0.046$) young ($\sim$0.6 Gyr) post-merger cluster system A3376,
with a moderate shock front ( $v_{s}\sim$1630 km/s) observed as symmetric radio
relics. Exploiting the spectroscopic data from the wide-field OmegaWINGS survey
and the associated photometric information, our investigations reveal the
plausible effects of the dynamic post-merger environment differing from the
putative pre-merger cluster environment. The remnants of the pre-merger relaxed
cluster environment are realised through the existence of passive spiral
galaxies located in the central regions of the cluster between the two BCGs. We
discover A3376 to contain a population of massive $(M_{*}/M_{\odot})>10$) blue
regular star-forming spirals in regions of maximum merger shock influence but
exhibiting star formation rates similar to those in relaxed clusters at similar
epoch. We further discover low-mass (Log $(M_{*}/M_{\odot})\leq 10$) late-type
blue PSBs which could either be formed as a result of rapid quenching of
low-mass spirals following the shock-induced star formation or due to the
intense surge in the ICM pressures at the beginning of the merger. With the
possibility of the merger shock affecting high- and low-mass spirals
differently, our results bridge the seemingly contradictory results observed in
known merging cluster systems so far and establish that different environmental
effects are at play right from pre- to post-merger stage.
