GCIRS 13E

GCIRS 13E is potentially an intermediate mass black hole (IMBH) with a mass of about 1300 Solar masses orbiting about three light years from the supermassive black hole Sagittarius A* at the center of the Milky Way galaxy. Its orbital velocity is 280 kilometers per second. [http://www.solstation.com/x-objects/s2.htm S2 and Central Black Hole] ]

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 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. [cite journal| id=arxiv|astro-ph|0504474 | title= A Black Hole in the Galactic Center Complex IRS 13E?| first= R.| last= Schoedel| coauthors= A. Eckart, C. Iserlohe, R. Genzel, T. Ott| journal= Astrophys. J.| volume= 625| year=2005| pages= L111–L114 | doi= 10.1086/431307] This conclusion is based on a dynamical study of a small star cluster in which should reside the suspected intermediate mass black hole. The debate on the real existence of intermediate mass black holes is still open.

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