Appears to be an Advanced Rapid Colony ship, 7th generation. As the name suggests, meant for colonization efforts, the dome at the center can sustain up to one million standard humanoids and supporting ecosystem in comfortable conditions for hundreds of cycles, plus in-built factories and heavy armaments plus other defensiver measures. The history of such models is hard to track off since they often leave to far away places where they may get lost or destroyed and nobody ever know. Even when they do succeed, they often end cannibalized by the new colony for spare parts. Although there seems to be plant life inside, there's no sign of actual colonists or crew inside.