Deep images of 10 early-type galaxies in low-density environments have been obtained with the Advanced Camera for Surveys ( ACS ) on the Hubble Space Telescope .
The global properties of the globular cluster ( GC ) systems of the galaxies have been derived in order to investigate the role of the environment in galaxy formation and evolution .
Using the ACS Virgo Cluster Survey ( ACSVCS ) as a high-density counterpart , the similarities and differences between the GC properties in high- and low-density environments are presented .
We find a strong correlation of the GC mean colours and the degree of colour bimodality with the host galaxy luminosity in low-density environments , in good agreement with high-density environments .
In contrast , the GC mean colours at a given host luminosity are somewhat bluer ( \Delta ( g - z ) \sim 0.05 ) than those for cluster galaxies , indicating more metal-poor ( \Delta [ Fe / H ] \sim 0.10 - 0.15 ) and/or younger ( \Delta age > 2 Gyr ) GC systems than those in dense environments .
Furthermore , with decreasing host luminosity , the colour bimodality disappears faster , when compared to galaxies in cluster environments .
Our results suggest that : ( 1 ) in both high- and low-density environments , the mass of the host galaxy has the dominant effect on GC system properties , ( 2 ) the local environment has only a secondary effect on the history of GC system formation , ( 3 ) GC formation must be governed by common physical processes across a range of environments .