Aggro radius
From Star Wars: The Old Republic Wiki
The range within which a hostile NPC will initiate combat with a player. When an NPC is outside this range it will not engage a player in combat unless the player directs a hostile action towards the NPC. Aggro radius simulates a hostile NPC 'seeing' the player and prevents players from immediately being swarmed and killed upon entering an area filled with many hostile NPC's.
