KITP: intermediate mass black holes in clusters

we contemplate intermediate mass black holes and their possible presence in globular clusters

Eva gives us the summary:

Intermediate mass black holes, conventionally black holes with masses > 100 solar masses and less than about 10,000 solar masses, are interesting and useful beasties.
If any such things exist.

There are hints - superluminous x-ray sources in other galaxies in particular, and theoretical paths by which they could be made.

Several ways to make them suggest they ought to end up in the centers of globular clusters, and there have been repeated claims suggesting observational hints of IMBHs in various globulars.

Ways in which you might see the sign of an IMBH are in the surface light profile of the cluster; the velocity dispersion of the cluster; or through kinematic anomalies in, for example, the cluster pulsar population.
There may be other indicators, which may be contemplated at some point.

The easiest is the surface light profile - there are several subtleties to that approach though:
one is defiining the cluster center consistently, this is surprisingly hard;
another is the fact that you just run out of stars as you try to define an asymptotic light profile as you approach the center;
and, then there is the question of what the actual signature is - theoretically you expect a strong central density divergence, a cusp, near a dynamically significant black hole, but, this may happen predominantly for the massive core remnants, like the neutron stars, and the light - the visible stars - may actually go into a very broad nearly flat profile, with maybe a very weak divergent cusp.



zoomable - try it, it is gorgeous

BIG original version

Tricky.

original conclusion deleted as being entirely too silly and not suitable for public consumption

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