The effect of gas loss on the formation of bound stellar clusters

By Michael P. Geyer, A. Burkert. 2000

136 citations recorded by the source corpus.

The effect of gas ejection on the structure and binding energy of newly formed stellar clusters is investigated. The star formation efficiency (SFE), necessary for forming a gravitationally bound stellar cluster, is determined. Two sets of numerical N-body simulations are presented. As a first simplified approach we treat the residual gas as an external potential. The gas expulsion is approximated by reducing the gas mass to zero on a given time-scale, which is treated as a free parameter. In a second set of simulations we use smoothed particle hydrodynamics (SPH) to follow the dynamics of the outflowing residual gas self-consistently. We investigate cases where gas outflow is induced by an outwards propagating shock front and where the whole gas cloud is heated homogeneously, leading to ejection. If the stars are in virial equilibrium with the gaseous environment initially, bound clusters only form in regions where the local SFE is larger than 50 per cent or where the gas expulsion time-scale is long compared with the dynamical time-scale. A small initial velocity dispersion of the stars leads to a compaction of the cluster during the expulsion phase and reduces the SFE needed to form bound clusters to less than 10 per cent.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/c7e8f0b8e4c11ed8fc14a6316992f6084a7186fb

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Citations in the corpus

The Origin of the Double Main Sequence in ω Centauri: Helium Enrichment due to Gas Fueling from Its Ancient Host Galaxy? (2005, unknown): “…models with s1 ≤ 1.75 become smaller than the threshold value (0.5) below which star clusters can be disintegrated as the result of mass loss (e.g., Geyer & Burkert 2001): No models can be located within the regions with 0.25 ≤ f2nd/(f1st + f2nd) ≤ 0.35 and with frem ≥ 0.5 where ω Cen can…”
On the fraction of star formation occurring in bound stellar clusters (2012, background): “…is then decimated due to the expulsion of residual gas by feedback (e.g. Tutukov 1978; Hills 1980; Lada, Margulis & Dearborn 1984; Adams 2000; Geyer & Burkert 2001; Boily & C© 2012 The Author Monthly Notices of the Royal Astronomical Society C© 2012 RAS Downloaded from…”
Embedded Clusters in Molecular Clouds (2003, background): “…problems that have been studied extensively both analytically (e.g., Elmegreen 1983, Hills 1980, Verschueren & David 1989) and numerically (Geyer & Burkert 2001; Goodwin 1997; Kroupa, Aarseth & Huley 31 Jul 2003 21:33 AR AR194-AA41-03.tex AR194-AA41-03.sgm LaTeX2e(2002/01/18) P1: GJB 106…”
Early Evolution of Stellar Groups and Clusters: Environmental Effects on Forming Planetary Systems (2005, background): “The fraction of stars that remain gravitationally bound after gas removal has been explored both analytically (e.g., Adams 2000; Boily & Kroupa 2003a) and numerically (e.g., Lada et al. 1984; Geyer & Burkert 2001; Boily & Kroupa 2003b).”
Formation of Globular Clusters in Hierarchical Cosmology (2003, background): “As a result of the gradual loss of the remaining gas, the star cluster expands almost adiabatically (e.g., Geyer & Burkert 2001; Boily & Kroupa 2003) such that its final size is R ¼ 1 RCSF ¼ 1 Rcell cell 3 CSF 1=2 : ð4Þ The resulting average density of the clusters is M 4 =3ð ÞR3 ¼ 4 Mg RCSFð Þ 4…”
A comprehensive set of simulations studying the influence of gas expulsion on star cluster evolution (2007, methodology): “Geyer & Burkert (2001) used King W0 = 3 and W0 = 5 models in their runs, which are significantly less concentrated than the Plummer models we use.”
The dynamical state of stellar structure in star‐forming regions (2011, background): “…largely based on the assumption of either a static gas potential1 or initial equilibrium between the stars and gas (e.g. Tutukov 1978; Adams 2000; Geyer & Burkert 2001; Boily & Kroupa 2003a,b; Baumgardt & Kroupa 2007; Parmentier et al. 2008), which need not apply to star-forming regions in…”
The Dramatic Size Evolution of Elliptical Galaxies and the Quasar Feedback (2008, background): “…new virial equilibrium can be inferred from numerical simulations of stellar cluster , which show that the system reaches the new equilibrium after about 40 dynamical times (computed for the initial configuration), independently of the initial mass (Geyer & Burkert 2001; Goodwin & Bastian 2006).”
Masses of Star Clusters in the Nuclei of Bulgeless Spiral Galaxies (2004, background): “Otherwise the gas blown out by feedback will invariably puff up the cluster to a much bigger size (e.g. Geyer & Burkert 2001).”
Photoionizing feedback in star cluster formation (2005, background): “See also Goodwin (1997), Adams (2000), Geyer & Burkert (2001) and Boily & Kroupa (2003) for more sophisticated analyses of this problem.”
Evidence for the Strong Effect of Gas Removal on the Internal Dynamics of Young Stellar Clusters (2006, unknown): “The expulsion of residual gas from star clusters has been modelled by several authors (see in particular Lada et al. 1984; Goodwin 1997a,b; Geyer & Burkert 2001; Kroupa, Aarseth & Hurley 2001; Boily & Kroupa 2003a,b).”
Young Massive Star Clusters (2010, background): “If texp > tdyn, the cluster is likely to survive; in particular, the core may respond with just a slight expansion (of at most a factor of 2), even in extreme cases, fe <∼ 0.1 (Geyer & Burkert 2001).”
On the mass function of star clusters (2002, unknown): “LMD, and subsequent work with much higher Necl by Goodwin (1997, 1998) and Geyer & Burkert (2001), confirmed Hills’ and Mathieu’s result.”
Gas expulsion and the destruction of massive young clusters (2006, unknown): “A number of authors have modelled the effect of gas expulsion on star clusters (e.g. Lada, Margulis & Dearborn 1984; Goodwin 1997a,b; Geyer & Burkert 2001; Kroupa, Aarseth & Hurley 2001; Kroupa & Boily 2002; Boily & Kroupa 2003a,b).”