Black holes in Gobular Clusters

Globular clusters are old star clusters.  For more information: http://michastrostudent.blogspot.com/2012/10/globular-clusters.html

Globular clusters are very old, upwards of 12 billion years old. Since they are so old all of the higher mass stars, that were originally found in the cluster, are all dead.  When I say dead I mean they have already passed through all the stages of a normal star ( http://michastrostudent.blogspot.com/2012/09/life-cycles-of-stars.html) and now are black holes. Black holes are high density objects that emit no light. For more information: http://michastrostudent.blogspot.com/2012/09/black-holes-neutron-stars-and-white.html

There are usually 100 to 1000 black holes in globular cluster.  Since globular clusters have very dense environments astronomers have discovered many black hole binary systems.  These binaries can produce extremely high amounts of X-ray emission because the two black holes magnetic fields interact.