HI in the Arp 202 system and its tidal dwarf candidate
  We present results from our Giant Metrewave Radio Telescope (GMRT) HI
observations of the interacting pair Arp 202 (NGC 2719 and NGC 2719A). Earlier
deep UV(GALEX) observations of this system revealed a tidal tail like extension
with a diffuse object towards its end, proposed as a tidal dwarf galaxy (TDG)
candidate. We detect HI emission from the Arp 202 system, including HI
counterparts for the tidal tail and the TDG candidate. Our GMRT HI
morphological and kinematic results clearly link the HI tidal tail and the HI
TDG counterparts to the interaction between NGC 2719 and NGC 2719A, thus
strengthening the case for the TDG. The Arp 202 TDG candidate belongs to a
small group of TDG candidates with extremely blue colours. In order to gain a
better understanding of this group we carried out a comparative study of their
properties from the available data. We find that HI (and probably stellar)
masses of this extremely blue group are similar to the lowest HI mass TDGs in
the literature. However the number of such blue TDG candidates examined so far
is too small to conclude whether or not their properties justify them to be
considered as a subgroup of TDGs.
