Sagittarius II, Draco II and Laevens 3: three new Milky Way satellites
  discovered in the Pan-STARRS 1 3pi Survey
  We present the discovery of three new Milky Way satellites from our search
for compact stellar overdensities in the photometric catalog of the Panoramic
Survey Telescope and Rapid Response System 1 (Pan-STARRS 1, or PS1) 3pi survey.
The first satellite, Laevens 3, is located at a heliocentric distance of
d=67+/-3 kpc. With a total magnitude of Mv=-4.4+/-0.3 and a half-light radius
rh=7+/-2 pc, its properties resemble those of outer halo globular clusters. The
second system, Draco II/Laevens 4 (Dra II), is a closer and fainter satellite
(d~20 kpc, Mv =-2.9+/-0.8), whose uncertain size (rh = 19 +8/-6 pc) renders its
classification difficult without kinematic information; it could either be a
faint and extended globular cluster or a faint and compact dwarf galaxy. The
third satellite, Sagittarius II/Laevens 5 (Sgr II), has an ambiguous nature as
it is either the most compact dwarf galaxy or the most extended globular
cluster in its luminosity range (rh = 37 +9/-8 pc and Mv=-5.2+/-0.4). At a
heliocentric distance of 67+/-5 kpc, this satellite lies intriguingly close to
the expected location of the trailing arm of the Sagittarius stellar stream
behind the Sagittarius dwarf spheroidal galaxy (Sgr dSph). If confirmed through
spectroscopic follow up, this connection would locate this part of the trailing
arm of the Sagittarius stellar stream that has so far gone undetected. It would
further suggest that Sgr II was brought into the Milky Way halo as a satellite
of the Sgr dSph.
