2018/01/26 by Paolo Bianchini, Jeremy J. Webb, Alison Sills +1 · 1 citation
Physics and Astronomy · #Stellar, planetary, and galactic studies #Gamma-ray bursts and supernovae #Astrophysics and Star Formation Studies
paper · doi:10.1093/mnrasl/sly013
openalex publication_date 2018/01/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Dynamical evolution drives globular clusters towards core collapse, which strongly shapes their internal properties. Diagnostics of core collapse have so far been based on photometry only, namely on the study of the concentration of the density profiles. Here, we present a new method to robustly identify core-collapsed clusters based on the study of their stellar kinematics. We introduce the kinematic concentration parameter, ck, the ratio between the global and local degree of energy equipartition reached by a cluster, and show through extensive direct N-body simulations that clusters approaching core collapse and in the post-core collapse phase are strictly characterized by ck > 1. The kinematic concentration provides a suitable diagnostic to identify core-collapsed clusters, independent from any other previous methods based on photometry. We also explore the effects of incomplete radial and stellar mass coverage on the calculation of ck and find that our method can be applied to state-of-art kinematic data sets.