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On the uniqueness of kinematical signatures of intermediate-mass black holes in globular clusters

Published online by Cambridge University Press:  07 March 2016

Alice Zocchi
Affiliation:
Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom email: a.zocchi@surrey.ac.uk
Mark Gieles
Affiliation:
Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom email: a.zocchi@surrey.ac.uk
Vincent Hénault-Brunet
Affiliation:
Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom email: a.zocchi@surrey.ac.uk
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Abstract

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Finding an intermediate-mass black hole (IMBH) in a globular cluster (GC), or proving its absence, is a crucial ingredient in our understanding of galaxy formation and evolution. The challenge is to identify a unique signature of an IMBH that cannot be accounted for by other processes. Observational claims of IMBH detection are often based on analyses of the kinematics of stars, such as a rise in the velocity dispersion profile towards the centre. In this contribution we discuss the degeneracy between this IMBH signal and pressure anisotropy in the GC. We show that that by considering anisotropic models it is possible to partially explain the innermost shape of the projected velocity dispersion profile, even though models that do not account for an IMBH do not exhibit a cusp in the centre.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2016 

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