The Dynamics of Superbubbles in the Large Magellanic Cloud

Abstract

Based on the stellar populations observed within this sample of LMC superbubbles, I use a numerical version of the standard, pressure-driven bubble model to investigate the shell dynamics. The results fall into two distinct categories corresponding to (1) a subset of objects for which the observed expansion velocity is too large for the observed shell radius ("high-velocity" superbubbles) and (2) a subset of objects that appears more dynamically consistent with the model ("low-velocity" superbubbles). Both subsets of objects imply an overestimate in the shell growth rate equivalent to an overestimate in input power by up to an order of magnitude. The high-velocity objects exhibit X-ray evidence of supernova activity, suggesting that the dynamical discrepancy is due to acceleration by supernova remnant impacts.