Mon. Not. R. Astron. Soc., 431, L1-L5 (2013/May-1)
Unusual displacement of HI due to tidal interaction in Arp 181.
SENGUPTA C., DWARAKANATH K.S., SAIKIA D.J. and SCOTT T.C.
Abstract (from CDS):
We present results from Giant Metrewave Radio Telescope Hi 21cm line observations of the interacting galaxy pair Arp 181 (NGC3212 and NGC3215) at z = 0.032. We find almost all of the detected Hi (90 per cent) is displaced well beyond the optical discs of the pair with the highest density Hi located ∼ 70kpc west of the pair. An Hi bridge extending between the optical pair and the bulk of 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), ultraviolet (UV; GALEX) and Hα 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 NGC3212 and, previously proposed to be a tidal dwarf galaxy in formation. Future sensitive Hi surveys by telescopes like Australian Square Kilometre Array Pathfinder 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.