Unusual displacement of HI due to tidal interaction in Arp 181
  We present results from GMRT HI 21 cm line observations of the interacting
galaxy pair Arp 181 (NGC 3212 and NGC 3215) at z =0.032. We find almost all of
the detected HI (90%) displaced well beyond the optical disks of the pair with
the highest density HI located ~70 kpc west of the pair. An HI bridge extending
between the optical pair and the bulk of the HI together with their HI
deficiencies provide strong evidence that the interaction between the pair has
removed most of their HI to the current projected position. HI to the west of
the pair has two approximately equal intensity peaks. The HI intensity maximum
furthest to the west coincides with a small spiral companion SDSS
J102726.32+794911.9 which shows enhanced mid-infrared (Spitzer), UV (GALEX) and
H alpha emission indicating intense star forming activity. The HI intensity
maximum close to the Arp 181 pair, coincides with a diffuse optical cloud
detected in UV (GALEX) at the end of the stellar and HI tidal tails originating
at NGC 3212 and, previously proposed to be a tidal dwarf galaxy in formation.
Future sensitive HI surveys by telescopes like ASKAP should prove to be
powerful tools for identifying tidal dwarfs at moderate to large redshifts to
explore in detail the evolution of dwarf galaxies in the Universe.
