Abstract

Contributed Talk - Splinter StarClusters

Tuesday, 08 September 2026, 15:15   (MW-2050)

Learning the Evolution of Massive Objects in Star Clusters

Saavedra-Bastidas, Jorge
ITA/ZAH, Univ. of Heidelberg

Intermediate-mass black holes (IMBHs) are believed to form in dense stellar systems through gravitational processes that couple the initial structure of the host cluster to its subsequent dynamical evolution. We investigate the extent to which the initial structural properties of globular clusters (GCs) encode the subsequent mass growth of their IMBH, independent of the intervening dynamical history. We use 323 MOCCA simulations of GCs that form an IMBH, extracting initial cluster properties, dimensionless phase variables, and the mass evolution of the most massive object (MMO) in each cluster. Under a supervised regression framework, we compare seven ML algorithms with different inductive biases, interpreting the best models via permutation importance, SHAP, and gradient-based feature attribution. Our best model recovers 94\% of the variance ($R^2=0.941$) in the IMBH mass fraction, while a linear baseline captures under 56\%, confirming the mapping is irreducibly nonlinear. Core-collapse timescale, initial seed mass of the MMO, and the initial core density consistently emerge as the dominant predictors. We observe difficulties when predicting a small population of extremely concentrated, near-gravothermal clusters, where few-body processes are not captured by global structural parameters. Our framework offers a computationally efficient tool for exploring IMBH growth across broad regions of initial-condition parameter space and may extend naturally to other classes of collisional stellar systems.