Modelling gas evacuation mechanisms in present-day globular clusters: Stellar winds from evolved stars and pulsar heating

We employ hydrodynamical simulations to investigate the underlying mechanism responsible for the low levels of gas and dust in globular clusters. Our models examine the competing effects of energy and mass supply from the various components of the evolved stellar population for globular clusters 47 Tucanae, M15, NGC 6440, and NGC 6752. Ignoring all other gas evacuation processes, we find that the energy output from the stars that have recently turned off the main sequence are capable of effectively clearing the evolved stellar ejecta and producing intracluster gas densities consistent with current observational constraints. This result distinguishes a viable gas and dust evacuation mechanism that is ubiquitous among globular clusters. In addition, we extend our analysis to probe the efficiency of pulsar wind feedback in globular clusters. We find that if the energy supplied by the pulsar winds is effectively thermalized within the intracluster medium, the material would become unbound. The detection of intracluster ionized gas in 47 Tucanae allows us to place particularly strict limits on pulsar wind thermalization efficiency, which must be extremely low in the cluster's core in order to be in accordance with the observed density constraints.