On the Heating Efficiency Derived from Observations of Young Super Star Clusters in M82

Abstract

Here we discuss the mechanical feedback that massive stellar clusters provide to the interstellar medium of their host galaxy. We apply an analytic theory developed in a previous study for M82-A1 to a sample of 10 clusters located in the central zone of the starburst galaxy M82, all surrounded by compact and dense HII regions. We claim that the only way that such HII regions can survive around the selected clusters, is if they are embedded into a high pressure ISM and if the majority of their mechanical energy is lost within the star cluster volume via strong radiative cooling. The latter implies that these clusters have a low heating efficiency, $\eta$, and evolve in the bimodal hydrodynamic regime. In this regime the shock-heated plasma in the central zones of a cluster becomes thermally unstable, loses its pressure and is accumulated there, whereas the matter injected by supernovae and stellar winds outside of this volume forms a high velocity outflow - the star cluster wind. We calculated the heating efficiency for each of the selected clusters and found that in all cases it does not exceed 10% . Such low heating efficiency values imply a low mechanical energy output and the impact that the selected clusters provide to the ISM of M82 is thus much smaller than what one would expect using stellar cluster synthetic models.

15 pages, 3 figures, accepted for publication in The Astrophysical Journal

References in corpus (8)

• HST/STIS Spectroscopy of Five Super Star Clusters in the Starburst Galaxy M82
• Two-Dimensional Hydrodynamic Models of Super Star Clusters with a Positive Star Formation Feedback
• On the hydrodynamics of the matter reinserted within superstellar clusters
• On the feedback from super stellar clusters. I. The structure of giant HII regions and HII galaxies
• Kinematics of gas and stars in the circumnuclear starforming ring of NGC 3351
• The pressure confined wind of the massive and compact superstar cluster M82-A1
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• Super stellar clusters with a bimodal hydrodynamic solution: an Approximate Analytic Approach

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• On the impact of radiation pressure on the dynamics and inner structure of dusty wind-driven shells
• Can Dust Injected by SNe Explain the NIR-MIR Excess in Young Massive Stellar Clusters?
• Massive Galaxies Impede Massive Outflows