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Abstract

Intermediate-mass black holes (IMBHs) with masses between $10^2$ to $10^5$ solar masses could be the key to explaining the formation of supermassive black holes in the centre of galaxies at high-redshift. The possible formation scenarios of IMBHs point towards dense stellar systems as favoured birthplaces. If an IMBH resides at the centre of such dense stellar systems, the surrounding stars under the IMBH’s dynamical influence will show characteristic kinematic signatures. During the last two decades, the community has made significant efforts to find IMBHs through these kinematic signatures, particularly in the centre of the Milky Way’s globular clusters (GCs). To date, however, no robust detection has been made.

In this thesis, we explore the internal dynamics of GCs to understand the current limitations for detecting IMBHs and propose alternative lines of evidence of their presence. With this purpose, we use numerical simulations of GCs with and without a central IMBH and apply commonly used dynamical models to estimate the mass of the possible central IMBH. We focus on the limitations of the dynamical modelling itself, particularly those due to common assumptions such as a constant velocity anisotropy and mass-to-light ratio. From an observational viewpoint, we explore the role of binaries in the observed kinematics and the connection between the observed binary fraction and the presence of an IMBH. Finally, we study the implications of the dynamical modelling limitations and the effects of binary systems on the scaling relations, which connect the mass of the central IMBHs with their host stellar system properties.