The AIMSS Project I: Bridging the Star Cluster - Galaxy Divide
  We describe the structural and kinematic properties of the first compact
stellar systems discovered by the AIMSS project. These spectroscopically
confirmed objects have sizes ($\sim$6 $<$ R$_{\rm e}$ [pc] $<$ 500) and masses
($\sim$2$\times$10$^{6}$ $<$ M$_*$/M$_\odot$ $<$ 6$\times$10$^{9}$) spanning
the range of massive globular clusters (GCs), ultra compact dwarfs (UCDs) and
compact elliptical galaxies (cEs), completely filling the gap between star
clusters and galaxies.
  Several objects are close analogues to the prototypical cE, M32. These
objects, which are more massive than previously discovered UCDs of the same
size, further call into question the existence of a tight mass-size trend for
compact stellar systems, while simultaneously strengthening the case for a
universal "zone of avoidance" for dynamically hot stellar systems in the
mass-size plane.
  Overall, we argue that there are two classes of compact stellar systems: 1)
massive star clusters and 2) a population closely related to galaxies. Our data
provide indications for a further division of the galaxy-type UCD/cE population
into two groups, one population that we associate with objects formed by the
stripping of nucleated dwarf galaxies, and a second population that formed
through the stripping of bulged galaxies or are lower-mass analogues of
classical ellipticals. We find compact stellar systems around galaxies in low
to high density environments, demonstrating that the physical processes
responsible for forming them do not only operate in the densest clusters.
