  Simultaneous observations of microlensing events from multiple locations
allow for the breaking of degeneracies between the physical properties of the
lensing system, specifically by exploring different regions of the lens plane
and by directly measuring the "microlens parallax". We report the discovery of
a 30-55$M_J$ brown dwarf orbiting a K dwarf in microlensing event
OGLE-2015-BLG-1319. The system is located at a distance of $\sim$5 kpc toward
the Galactic bulge. The event was observed by several ground-based groups as
well as by $Spitzer$ and $Swift$, allowing the measurement of the physical
properties. However, the event is still subject to an 8-fold degeneracy, in
particular the well-known close-wide degeneracy, and thus the projected
separation between the two lens components is either $\sim$0.25 AU or $\sim$45
AU. This is the first microlensing event observed by $Swift$, with the UVOT
camera. We study the region of microlensing parameter space to which $Swift$ is
sensitive, finding that while for this event $Swift$ could not measure the
microlens parallax with respect to ground-based observations, it can be
important for other events. Specifically, for detecting nearby brown dwarfs and
free-floating planets in high magnification events.
