Search for globular clusters associated with the Milky Way dwarf
  galaxies using Gaia DR2
  We report the result of searching for globular clusters (GCs) around 55 Milky
Way satellite dwarf galaxies within the distance of 450 kpc from the Galactic
Center except for the Large and Small Magellanic Clouds and the Sagittarius
dwarf. For each dwarf, we analyze the stellar distribution of sources in Gaia
DR2, selected by magnitude, proper motion, and source morphology. Using the
kernel density estimation of stellar number counts, we identify eleven possible
GC candidates. Crossed-matched with existing imaging data, all eleven objects
are known either GCs or galaxies and only Fornax GC 1-6 among them are
associated with the targeted dwarf galaxy. Using simulated GCs, we calculate
the GC detection limit $M_{\rm V}^{\rm lim}$ that spans the range from $M_{\rm
V}^{\rm lim} \sim -7$ for distant dwarfs to $M_{\rm V}^{\rm lim} \sim 0$ for
nearby systems. Assuming a Gaussian GC luminosity function, we compute that the
completeness of the GC search is above 90 percent for most dwarf galaxies. We
construct the 90 percent credible intervals/upper limits on the GC specific
frequency $S_{\rm N}$ of the MW dwarf galaxies: $12 < S_{\rm N} < 47$ for
Fornax, $S_{\rm N} < 20$ for the dwarfs with $-12 < M_{\rm V} < -10$, $S_{\rm
N} < 30$ for the dwarfs with $-10 < M_{\rm V} < -7$, and $S_{\rm N} < 90$ for
the dwarfs with $M_{\rm V} > -7$. Based on $S_{\rm N}$, we derive the
probability of galaxies hosting GCs given their luminosity, finding that the
probability of galaxies fainter than $M_{\rm V} = -9$ to host GCs is lower than
0.1.
