(globular cluster in which a black hole has been identified)
NGC 3201 (aka Caldwell 79) is a
globular cluster with a radius of 40 ly and a
presumed age of more than 10 gigayears (one determination
is 10.24 Gy).
It is of interest because a probable black hole
has been identified, using the radial velocity of a star
that indicates it is orbiting something unseen and very massive
(more mass than would be possible for a neutron star,
white dwarf or red dwarf).
It is assumed that globular clusters generally host
multiple stellar-mass black holes,
simply based upon the large number of resident stars,
but currently they can only be identified when specific clues are
available, such as in this case.