UGC 3672: An unusual merging triplet of gas-rich galaxies in the
  Lynx-Cancer void
  We present HI 21cm and optical observations of UGC 3672 which is located near
the centre of the nearby Lynx-Cancer void. We find that UGC 3672 consists of an
approximately linearly aligned triplet of gas rich dwarfs with large scale
velocity continuity along the triplet axis. The faintest component of the
triplet is extremely gas-rich (MHI/LB ~ 17) and also extremely metal deficient
(12+log(O/H) ~ 7.0). The metallicity of this dwarf is close to the 'floor'
observed in star forming galaxies. Low resolution HI images show that the
galaxy triplet is located inside a common HI envelope, with fairly regular,
disk like kinematics. At high angular resolution however, the gas is found to
be confined to several filamentary tidal tails and bridges. The linear
alignment of the galaxies, along with the velocity continuity that we observe,
is consistent with the galaxies lying along a filament. We argue that the
location of this highly unusual system in an extremely low density environment
is not a coincidence, but is a consequence of structure formation proceeding
more slowly and also probing smaller scales than in regions with average
density. Our observations also indicate that wet mergers of galaxies flowing
along filaments is a possible pathway for the formation of gas rich disks. The
UGC 3672 system provides an interesting opportunity to study the kind of
interactions typical between high redshift extremely gas rich unevolved small
systems that lie at base of the hierarchical galaxy formation model.
