[2] These stars are thought to be remnants of either the Milky Way's creation, or the merging of it with another small galaxy.
Both of these stars being cool red giants, they are extremely bright which is one of the key factors in their discovery.
In comparison, in distance to the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only 160,000 light-years from Earth.
ULAS J0015+01 has been thought to either be a remnant of the Milky Way's formation or a merger with a different galaxy.
Another hypothesis was it is part of an unknown galaxy with low surface brightness, but that seems unlikely.