On the mass function of star clusters

By Pavel Kroupa, C. Boily. 2002

181 citations recorded by the source corpus.

Clusters that form in total 10 3 <N <10 5 stars (type II clusters) lose their gas within a dynamical time as a result of the photo-ionising flux from O stars. Sparser (type I) clusters get rid of their residual gas on a timescale longer or comparable to the nominal crossing time and thus evolve approximately adiabatically. This is also true for massive embedded clusters (type III) for which the velocity dispersion is larger than the sound speed of the ionised gas. On expelling their residual gas, type I and III clusters are therefore expected to lose a smaller fraction of their stellar component than type II clusters. We outline the effect this has on the transformation of the mass function of embedded clusters (ECMF), which is directly related to the mass function of star-cluster-forming molecular cloud cores, to the “initial” MF of bound gas-free star clusters (ICMF). The resulting ICMF has, for a featureless power-law ECMF, a turnover near 10 4.5 M⊙ and a peak near 10 3 M⊙. The peak lies around the initial masses of the Hyades, Praesepe and Pleiades clusters. We also find that the entire Galactic population II stellar spheroid can be generated if star formation proceeded via embedded clusters distributed like a power-law MF with exponent 0.9< � < 2.6.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/df9d5b0a2ce97651a1a979987d1645ba3326ee38

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Citations in the corpus

Properties of stellar generations in globular clusters and relations with global parameters (2010, background): “…cluster mass function, not too dissimilar to the observed one, can be reproduced by a proper tuning of parameters (efficiency of star formation, initial central concentration, original mass distribution, initial stellar mass function: see e.g., Parmentier & Gilmore 2007; Kroupa & Boily 2002).”
Merging black holes in young star clusters (2019, background): “The recent detection of gravitational waves (GWs, Abbott et al. 2016b) by LIGO (Aasi et al. 2015) and Virgo (Acernese et al. 2015) has opened up a new way to investigate the Universe.”
The Variation of Integrated Star Initial Mass Functions among Galaxies (2005, background): “The situation may be resolved once early cluster evolution is taken into account in more detail; Kroupa & Boily (2002) have already made the important point that the cluster MF evolves rapidly within the first few 106 yr as a result of revirialization after significant residual-gas expulsion.”
Origin of the abundance patterns in Galactic globular clusters: constraints on dynamical and chemical properties of globular clusters (2007, background): “II stars found in the halo would comes largely from lower-mass clusters that dissolved after residual gas expulsion, as pointed out by Kroupa & Boily (2002).”
Embedded Clusters in Molecular Clouds (2003, background): “…clusters formed in such a manner, the stars lost in their emergence from their parental clouds could account for all the Population II 31 Jul 2003 21:33 AR AR194-AA41-03.tex AR194-AA41-03.sgm LaTeX2e(2002/01/18) P1: GJB EMBEDDED CLUSTERS 109 field stars in the Galactic halo (Kroupa & Boily 2002).”
STELLAR FEEDBACK IN MOLECULAR CLOUDS AND ITS INFLUENCE ON THE MASS FUNCTION OF YOUNG STAR CLUSTERS (2009, background): “Indeed, several authors have proposed that feedback would cause a bend in the mass function of young clusters at M ∼ 105M⊙, motivated in part by the well-known turnover in the mass function of old globular clusters (Kroupa & Boily 2002; Baumgardt et al. 2008; Parmentier et al. 2008).”
Formation of Globular Clusters in Hierarchical Cosmology (2003, background): “Within such cores, star clusters form with a locally high efficiency (Geyer & Burkert 2001; Kroupa et al. 2001; Kroupa & Boily 2002), M Mg k 0:5; ð1Þ which is required in order to produce gravitationally bound clusters.”
Implications for the formation of star clusters from extragalactic star formation rates (2004, background): “The cluster in NGC 7252 was excluded because this galaxy is a several 108 yr old merger in which the SFR was presumably much higher when most of its clusters formed and in which the brightest “cluster” is probably an unresolved or already merged star-cluster complex (Fellhauer & Kroupa 2002a), and t”
Chemical enrichment of the intracluster and intergalactic medium in a hierarchical galaxy formation model (2003, background): “On the other hand, many authors have argued that there is very little real observational evidence that the IMF does vary, at least between different regions of our own Galaxy (Massey 1998; Hernandez & Ferrara 2001; Kroupa & Boily 2002).”
The ACS Virgo Cluster Survey. XII. The Luminosity Function of Globular Clusters in Early-Type Galaxies (2007, background): “…if conditions were not just right, very many protoglobular clusters could have been easily destroyed inthe earliest 107 yr of their evolution, through the catastrophic mass loss induced by massive-star winds and supernova explosions (see, e.g., Kroupa & Boily 2002; Fall, Chandar & Whitmore 2005).”
The primordial binary population. I. A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2 (2004, unknown): “Note that OB associations may start out as dense clusters (Kroupa et al. 2001; Kroupa & Boily 2002).”
Gas expulsion and the destruction of massive young clusters (2006, unknown): “Those stars with a velocity greater than the new escape velocity tend to escape the cluster4 (see also Tutkov 1978; Goodwin 1997a,b; Kroupa & Boily 2002; Boily & Kroupa 2003a,b; BG06).”
The Birth Environment of the Solar System (2010, background): “…are found with membership size in the range N = 100 – 2000, the distribution of cluster number dfc/dN ∝ 1/N2, so that the probability density for a star being born in a system of size N has the form dP/dN ∝ 1/N (e.g., see Carpenter 2000, Kroupa & Boily 2002, Lada & Lada 2003, Porras et al. 2003).”
Theory of Star Formation (2007, background): “For sufficiently massive and concentrated clusters, the escape velocity exceeds the sound speed of ionized gas, and this can further increase the star formation efficiency (Kroupa & Boily, 2002; Matzner, 2002; Tan & McKee, 2004).”