Super massive star clusters: from superwinds to a cooling catastrophe and the re-processing of the injected gas

Silich, S.; Tenorio-Tagle, G.; Muñoz-Tuñon, C.; Palouš, J.
Bibliographical reference

Triggered Star Formation in a Turbulent ISM, Edited by B. G. Elmegreen and J. Palous. Proceedings of the International Astronomical Union 2, IAU Symposium #237, held 14-18 August, 2006 in Prague, Czech Republic. Cambridge: Cambridge University Press, 2007., pp.242-245

Advertised on:
0
2007
Number of authors
4
IAC number of authors
0
Citations
2
Refereed citations
2
Description
The presence of compact and massive star clusters is a characteristic property of many starburst and interacting galaxies. Their extreme mechanical and radiation energy outputs are now believed to be the largest negative feedback agents leading to a large-scale structuring of the ISM and limiting star formation in the host galaxies. The aim of our study is to understand how extreme star cluster parameters affect the hydrodynamics of the ejected material and find limitations on the development of the star cluster winds established by the strong radiative cooling. Our calculations are based on the Chevalier and Clegg (1985) concept of the galactic wind but also include radiative cooling as a crucial ingredient that affects outflows from the most massive and compact star clusters. We demonstrate that three different hydrodynamic regimes may exist: an adiabatic wind, as considered by Chevalier and Clegg, a strongly radiative solution and a catastrophic cooling regime when the stationary outflow is inhibited by a sudden loss of the injected energy promoted by radiative cooling. The continuous energy and mass deposition establishes then a new stationary regime. In this, the mass deposited by a star cluster, instead of causing a wind as in the adiabatic solution, turns into a positive feedback star-forming mode with extremely high star formation efficiency that allows for new forming entities to survive in the form of compact, gravitationally bound systems for a long time. Possible examples of this extreme positive feedback regime are discussed.