Globular clusters (GC) are powerful tools to analyse the Halo environment: spread throughout the Halo at distances of 2– 122 kpc, moving with space velocities of ∼200 km s−1, they provide unique tracers of local Halo conditions. Each cluster enriches the Halo with several M⊙ Myr−1 through stellar winds. The interaction of these winds with the Halo can be used as a probe of the local Halo environment.

Using spectral energy distributions of 6875 stars in the GC ω Cen, we quantify the cluster’s total mass loss. Comparing this to observed limits on intra-cluster material (ICM), we find the ICM is being cleared from these clusters on timescales of <105 yr. We also present new 21 cm observations of the high velocity H i cloud near ω Cen in the context of recent Spitzer observations, discussing its structure and likely associations.