Milky Way Halo Update

Here are some new data for my Milky Way halo page based on recent analyses of the Gaia DR2 releaae.

Some recent papers (see below) present Gaia-based evidence for several groups of globular clusters that came with their progenitor galaxies which were captured by the Milky Way. Apart from the already known Sagittarius and Gaia-Enceladus dwarf galaxies there are now Seqoia, a dwarf accreted about 10 Gyr ago, Omega Cen may be the its former nucleus. 21 associated GCs came from the somewhat larger Koala according to Forbes et al.(2020), as well as the Helmi stream, which may have been accreted 5 to 8 Gyrs ago. The number of 76 cluster between those 5 galaxies represent a significant fraction of the total for the Milky Way. 184 are known at the moment, some of the others also show characteristics of accretion but can not be associated with a known progenitor.

Krujissen et al. (2018) The formation and assembly history of the Milky Way revealed by its globular cluster population. arXiv:astro-ph/1806.05680v2
Massari et al. (2019)Origin of the system of globular clusters in the Milky Way. arXiv:astro-ph/1906.08271v2
Marsakov et al. (2020) Globular Clusters of the Galaxy: Chemical Composition vs Kinematics. arXiv:astro-ph/2002.10692v1
Forbes et al. (2020) Reverse engineering the Milky Way. arXiv:astro-ph/2002.01512v1