Indication for an intermediate-mass black hole in the globular cluster NGC 5286 from kinematics

Context. Intermediate-mass black holes (IMBHs) fill the gap between stellar-mass black holes and supermassive black holes (SMBHs). The existence of the latter is widely accepted, but there are only few detections of intermediate-mass black holes (102 − 105M⊙) so far. Simulations have shown that intermediate-mass black holes may form in dense star clusters, and therefore may still be present in these smaller stellar systems. Also, extrapolating the M•–σ scaling relation to lower masses predicts intermediate-mass black holes in systems with σ ~ 10 − 20 km s-1 such as globular clusters. Aims. We investigate the Galactic globular cluster NGC 5286 for indications of a central intermediate-mass black hole using spectroscopic data from VLT/FLAMES