of course as soon as i post that they get bored and leave
The Pirates will leave the gravity well after they have completed the mission they were sent on. In your typical scenario, they remained in the gravity well until all hostile objects were obliterated (all enemy ships and structures). This is basically how normal raids work as well.
Because you clearly researched Truce Amongst Rogues, the Pirates will not attack you and view you as friendly.
Conclusion: Pure TEC Rebel Awesomeness!