Method for detecting a boson star at Sgr A* through gravitational
  lensing
  Observations of the Sgr A* region in the galactic center confirm the presence
of a large amount of matter in a small volume, leading to the consensus that a
black hole exists there. However, dynamical observations cannot rule out the
presence of a boson star, a compact object made up of scalar particles, as both
objects are far more compact than the scale of current observational
constraints. While a boson star in the galactic center is disfavored for a
number of theoretical considerations, we outline the first test that can
directly observe a boson star. We accomplish this by studying the strong
gravitational lensing of S stars resulting from the assumption of a boson star
in the Galactic Center. Boson stars have an extended mass distribution and are
transparent to electromagnetic radiation, giving rise to a radial caustic
curve. We calculate the brightness of images formed by stars crossing these
radial caustics and show that a boson star would give rise to much brighter
images than a black hole with a similar mass and that those images would be
easily bright enough to be detected with upcoming instruments.
