Tidal origin of NGC 1427A in the Fornax cluster
  We present new HI observations from the Australia Telescope Compact Array and
deep optical imaging from OmegaCam on the VLT Survey Telescope of NGC 1427A, an
arrow-shaped dwarf irregular galaxy located in the Fornax cluster. The data
reveal a star-less HI tail that contains ~10% of the atomic gas of NGC 1427A as
well as extended stellar emission that shed new light on the recent history of
this galaxy. Rather than being the result of ram pressure induced
star-formation, as previously suggested in the literature, the disturbed
optical appearance of NGC 1427A has tidal origins. The galaxy itself likely
consists of two individual objects in an advanced stage of merging. The HI tail
may be made of gas expelled to large radii during the same tidal interaction.
It is possible that some of this gas is subject to ram pressure, which would be
considered a secondary effect and imply a northwest trajectory of NGC 1427A
within the Fornax cluster.
