We'll name it later

I propose we call it Bob. Gaia-Enceladus ? That's about the most out-of-touch name imaginable. Plus it's a lot to type. Thus :

Some 10 billion years ago, the Milky Way merged with a large galaxy. The stars from this partner, named Bob, make up most of the Milky Way's halo and also shaped its thick disk, giving it its inflated form. A description of this mega-merger, discovered by an international team led by University of Groningen astronomer Amina Helmi, is now published in the scientific journal Nature.

The chemical signature of many halo stars was clearly different from the 'native' Milky Way stars. "And they are a fairly homogenous group, which indicates they share a common origin." By plotting both trajectory and chemical signature, the 'invaders' stood out clearly. Helmi says, "The youngest stars from Bob are actually younger than the native Milky Way stars in what is now the thick disk region. This means that the progenitor of this thick disk was already present when the fusion happened, and Bob, because of its large size, shook it and puffed it up."

https://phys.org/news/2018-10-astronomers-giant-early-days-milky.html