Search for globular clusters associated with the Milky Way dwarf galaxies using Gaia DR2

Kuan-Wei Huang, Sergey E. Koposov

Research output: Contribution to journalArticlepeer-review


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 MlimV that spans the range from Mlim V ~ -7 for distant dwarfs to Mlim
V 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 SN of the MW dwarf galaxies: 12 < SN < 47 for Fornax,
SN < 20 for the dwarfs with -12 < MV < -10, SN < 30 for the dwarfs with -10 < MV < -7, and SN < 90 for the dwarfs with MV > -7. Based on SN, we derive the probability of galaxies hosting GCs given their luminosity, finding that the probability of galaxies fainter than MV = -9 to host GCs is lower than 0.1.
Original languageEnglish
Pages (from-to)986-997
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date27 Oct 2020
Publication statusPublished - 1 Jan 2021


  • astro-ph.GA


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