I ran across the image below in the August 2000 ESA Bulletin # 103 GAIA – Unravelling the Origin and Evolution of Our Galaxy
Figure 3. This simulation shows how a galaxy halo, like our own, may have been built up by the accretion of 50 dwarf galaxies colliding with the galaxy at various times during the last 10 billion years. The unit of distance is the kpc, or kiloparsec, where 1 kpc is a little more than 3000 lightyears. GAIA would be able to detect the fossil streams of these ancient merging events (Courtesy of Paul Harding)
Twenty years later, have results from GAIA been used to generate any data of this nature, identifying groups of stars that are likely to have come from nearby dwarf galaxies merging with our own?