Modelling the formation and evolution of star cluster populations in galaxy simulations

By J. Kruijssen, F. I. Pelupessy, Henny Lamers, S. P. Portegies Zwart, V. Icke. 2011

137 citations recorded by the source corpus.

The formation and evolution of star cluster populations are related to the galactic environment. Cluster formation is governed by processes acting on galactic scales, and star cluster disruption is driven by the tidal field. In this paper, we present a self-consistent model for the formation and evolution of star cluster populations, for which we combine an N-body/smoothed particle hydrodynamics galaxy evolution code with semi-analytical models for star cluster evolution. The model includes star formation, feedback, stellar evolution and star cluster disruption by two-body relaxation and tidal shocks. The model is validated by a comparison to N-body simulations of dissolving star clusters. We apply the model by simulating a suite of nine isolated disc galaxies and 24 galaxy mergers. The evolutionary histories of individual clusters in these simulations are discussed to illustrate how the environment of clusters changes in time and space. It is found that the variability of the disruption rate with time and space affects the properties of star cluster populations. In isolated disc galaxies, the mean age of the clusters increases with galactocentric radius. The combined effect of clusters escaping their dense formation sites (‘cluster migration’) and the preferential disruption of clusters residing in dense environments (‘natural selection’) implies that the mean disruption rate of the population decreases with cluster age. This affects the slope of the cluster age distribution, which becomes a function of the star formation rate density (star formation rate per unit volume). The evolutionary histories of clusters in a galaxy merger vary widely and determine which clusters survive the merger. Clusters that escape into the stellar halo experience low disruption rates, while clusters orbiting near the starburst region of a merger are disrupted on short time-scales due to the high gas density. This impacts the age distributions and the locations of the surviving clusters at all times during a merger. The paper includes a discussion of potential improvements for the model and a brief exploration of possible applications. We conclude that accounting for the interplay between the formation, disruption and orbital histories of clusters enables a more sophisticated interpretation of observed properties of cluster populations, thereby extending the role of cluster populations as tracers of galaxy evolution.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b95725e34fff81c6928404e761a1cd37d5239808

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Citations in the corpus

On the fraction of star formation occurring in bound stellar clusters (2012, methodology): “(48) Note that the aforementioned models of Prieto & Gnedin (2008) and Kruijssen et al. (2011) account for the tidal disruption of clusters from the moment they are born.”
The dragon simulations: globular cluster evolution with a million stars (2016, background): “…massive black hole are further dynamical complications (e.g. Lamers, Gieles, & Portegies Zwart 2005; Hurley 2007; Portegies Zwart et al. 2004; Kruijssen et al. 2011; Gieles, Heggie, & Zhao 2011; Giersz et al. 2015), not to speak of the recent detection of possible dynamically distinct…”
What controls star formation in the central 500 pc of the Galaxy (2013, background): “The disruption of a104 M⊙ cluster in a gas-rich, high-density environment is dominated by tidal shocks due to GMC passages (Elmegreen & Hunter 2010; Kruijssen et al. 2011, 2012).”
The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline (2014, background): “About50% of the star formation in the CMZ is thought to occur in bound clusters as shown by observations (Mauerhan et al. 2010) and theory (Kruijssen 2012), ofwhich the majority is destroyed on time-scales of∼ 10 Myr (see e.g. Portegies Zwart et al. 2001; Kruijssen et al. 2011, 2014).”
Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy (2016, background): “…(2010) championed the notion that newborn clusters are efficiently destroyed by tidal interaction with GMCs, which are present in the very environment that initially gave birth to clusters—the so called c© 2015 RAS, MNRAS 000, 2–27 “cruel cradle effect” (see also Kruijssen et al. 2011, 2012).”
Globular clusters as the relics of regular star formation in ‘normal’ high-redshift galaxies (2015, methodology): “As such, the surviving clusters in the merger remnant predate the main starburst and typically have ages up to200 Myr older than the field stars formed in a merger (Kruijssen et al. 2011).”
Dynamics of stellar black holes in young star clusters with different metallicities – II. Black hole–black hole binaries (2014, background): “Finally, GCs are old ( 12 Gyr) and long-lived systems, whereas YSCs are young and short lived: most of them E-mail: brunetto.ziosi@gmail.com dissolve in the disc of the host galaxy in ≤108 yr (e.g. Kruijssen et al. 2011).”
Probing the role of the galactic environment in the formation of stellar clusters, using M83 as a test bench (2015, background): “…(Σ > 103 M⊙ pc−2) is that tidal perturbations by dense giant molecular clouds unbind lower-density clusters that otherwise would have survived (cf. Kruijssen et al. 2011). c© 2015 RAS, MNRAS 000, 1–?? spatially resolved data points in M 83 as well as for a compilation of literature…”
The dynamical state of stellar structure in star‐forming regions (2011, background): “Recent papers have argued that the disruption of star clusters due to tidal shocksfrom the natal environment could be substantial (Elmegreen & Hunter 2010; Kruijssen et al. 2011; Kruijssen & Bastian, in prep.).”
The formation and assembly history of the Milky Way revealed by its globular cluster population (2018, methodology): “Thirdly, we include mass loss by two-body interactions between the stars in a cluster (Kruijssen et al. 2011, see also Lamers et al. 2005).”