The Role of Ground-Based Robotic Observatories in Satellite Projects
The distribution of optical magnitudes of optically identified INTEGRAL gamma-ray sources. Most are brighter than mag 20, and more than half are brighter than mag 15. Legend dark blue mag 2–6, orange mag 5–10, yellow mag 10–14, green mag 14–18, purple mag 18–22, light blue mag 22–26. The numbers in the plot indicate number of objects with optical magnitude within the indicated range.