On the evolution of intracluster gas within Galactic globular clusters

Abstract

It has been known since the 1950s that the observed gas content of Galactic globular clusters (GCs) is two to three orders of magnitude less than the mass lost by stars between Galactic disc crossings. In this work, we address the question: what happens to this stellar gas? Using an Eulerian nested grid code, we present 3D simulations to determine how stellar wind material evolves within the GC environment. We expand upon work done in the 1970s and move a single-mass King-model GC through the Galactic halo medium, stripping a 105M⊙ GC of its intracluster medium but predicting a detectable medium for a 106M⊙ cluster. We find from new multi-mass King-model simulations, the first to incorporate empirical mass-loss formulae, that the single-mass King model underestimates the retention of intracluster gas in the cluster. Lastly, we present a simple discretized multi-mass GC model, which yields lower levels of intracluster medium compared to the continuous single- and multi-mass King models. Our results show that there is still an issue with the predicted intracluster gas content of massive GCs. We conclude that by modelling GC systems more accurately, in particular the stellar structure and description of mass loss, we will be able to work towards resolving this issue and begin to fill in some of the gaps in our understanding of the evolution of GCs. © 2010 The Authors Monthly Notices of the Royal Astronomical Society © 2010 RAS.