Radial Variation in the Stellar Mass Functions of Star Clusters

Abstract

A number of recent observational studies of Galactic globular clusters have measured the variation in the slope of a cluster's stellar mass function $\alpha$ with clustercentric distance $r$. In order to gather a deeper understanding of the information contained in such observations, we have explored the evolution of $\alpha (r)$ for star clusters with a variety of initial conditions using a large suite of $N$-body simulations. We have specifically studied how the time evolution of $\alpha (r)$ is affected by initial size, mass, binary fraction, primordial mass segregation, black hole retention, an external tidal field, and the initial mass function itself. Previous studies have shown that the evolution of ${\alpha }_G$ is closely related to the amount of mass loss suffered by a cluster. Hence for each simulation we have also followed the evolution of the slope of the cluster's global stellar mass function, ${\alpha }_G$, and have shown that clusters follow a well-defined track in the ${\alpha }_G$-$d\alpha (r)/d(ln(r/r_m))$ plane. The location of a cluster on the ${\alpha }_G-d\alpha (r)/d(ln(r/r_m))$ plane can therefore constrain its dynamical history and, in particular, constrain possible variations in the stellar initial mass function. The ${\alpha }_G$-$d\alpha (r)/d(ln(r/r_m))$ plane thus serves as a key tool for fully exploiting the information contained in wide field studies of cluster stellar mass functions.

13 pages, 13 figures, 1 table, Accepted for publication in MNRAS

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Cited by in corpus (15)

• The global mass functions of 35 Galactic globular clusters: I. Observational data and correlations with cluster parameters
• The Global Mass Functions of 35 Galactic globular clusters: II. Clues on the Initial Mass Function and Black Hole Retention Fraction
• Do star clusters form in a completely mass-segregated way?
• Ultra-deep GEMINI near-infrared observations of the bulge globular cluster NGC 6624
• On the Link Between Energy Equipartition and Radial Variation in the Stellar Mass Function of Star Clusters
• New insights into star cluster evolution towards energy equipartition
• Modelling the Observed Stellar Mass Function and its Radial Variation in Galactic Globular Clusters
• The family pictures of our neighbours: investigating the mass function and dynamical parameters of nearby open clusters
• The structure of accreted stellar streams
• Variation in the Stellar Mass Function Along Stellar Streams
• Correlation Between Mass Segregation and Structural Concentration in Relaxed Stellar Clusters
• The evolution of kicked stellar-mass black holes in star cluster environments II. Rotating star clusters
• Stellar collisions in globular clusters: Constraints on the initial mass function of the first generation of stars
• Made-to-Measure Modelling of Globular Clusters
• Predicting Images for the Dynamics Of stellar Clusters (π-DOC): a deep learning framework to predict mass, distance and age of globular clusters