Gaia spots a 'ghost' galaxy next door

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What makes Ant 2 even more unusual is how little light it gives out. Compared to the LMC, another satellite of the Milky Way, Ant 2 is 10,000 times fainter. In other words, it is either far too large for its luminosity or far too dim for its size.

The scifi nerd in me wants to believe it's a result of an ancient civilisation shrouding huge numbers of stars in Dyson Spheres, waiting until they collided with the next galaxy that they could feed on.

The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2

https://arxiv.org/pdf/1811.04082