  We present results from a study of Type I critical phenomena in the dynamics
of general relativistic boson stars in spherical symmetry. The boson stars are
modelled with a minimally coupled, massive complex field (with no explicit
self-interaction), and are driven to the threshold of black hole formation via
their gravitational interaction with an initially imploding pulse of massless
scalar field. Using a distinct coordinate system, we reproduce previous results
[1,2], including the scaling of the lifetime of near-critical configurations,
as well as the fact that such configurations are well described as perturbed,
one-mode-unstable boson stars. In addition, we make a detailed study of the
long-time evolution of marginally subcritical configurations. Contrary to
previous claims [1,2], we find that the end state in such cases does not
involve dispersal of the bulk of the boson star field to large radial
distances, but instead can be generically described by a stable boson star
executing large amplitude oscillations. Furthermore we show that these
oscillations can be largely identified as excitations of the fundamental mode
associated with the final boson star, as computed in perturbation theory.
