GCIRS 13E is potentially an intermediate mass black hole (IMBH) with a mass of about 1300 solar masses orbiting Sagittarius A* at a distance of about three light years. Its orbital velocity is 280 kilometers per second.
GCIRS 13E is associated with a small cluster of seven massive stars orbiting it. It is thought that massive stars cannot form so close to a supermassive black hole and since such massive stars have a short lifespan it is thought that GCIRS 13E must have migrated inward toward the central black hole within the past 10 million years, probably from about 60 light-years further out than its current orbit. The companion stars are possibly the remains of a globular cluster where a middleweight black hole such as GCIRS 13E could develop through runaway star collisions.
In 2005, however, a German research group claimed that the presence of an IMBH near the galactic center is doubtful. This conclusion is based on a dynamical study of a small star cluster in which the suspected intermediate mass black hole should reside . The debate on the real existence of intermediate mass black holes is still open.