Astrometric Detection of Intermediate-Mass Black Holes At the Galactic
  Centre
  We assess the astrometric detectability of intermediate-mass black holes
populating the inner parsec of the Milky Way Galaxy. The presence of these
objects induces dynamical effects on Sgr A* and the star S2, which could be
detected by next generation astrometric instruments that enable micro-arcsecond
astrometry. An allowed population of ten $10^4~M_{\odot}$ IMBHs within one
parsec induces an angular shift of about 65 $\mu$as yr$^{-1}$ on the position
of Sgr A*, corresponding to a perpendicular velocity component magnitude of 1.6
km s$^{-1}$. It also induces changes in the orbit of S2 that surpass those
induced by general relativity but lie within observational constraints,
generating a mean angular shift in periapse and apoapse of 62 $\mu$as and 970
$\mu$as respectively.
