Mirror universe
(coexisting on another dimensional plane)
(coexisting on another dimensional plane)
The Fowla system was a star system located somewhere near Bajor.
Benjamin Sisko and his crew were on a mission in the Fowla system, when they were called back by Intendant Kira Nerys to meet Major Kira Nerys from her universe. (DS9: "Crossover")
This system was only mentioned in dialogue.