The SAGES Legacy Unifying Globulars and Galaxies Survey (SLUGGS) is a wide-field chemo-dynamical survey of early-type galaxies. It capitalizes on the unmatched observing power of the Subaru/Suprime-Cam imager and the Keck/DEIMOS spectrograph, combined with state-of-the-art simulations to interpret the observations in a cosmological context.
Spectroscopy of the near-infrared calcium triplet provides kinematic and metallicity information for stars (to ~3 effective radii) and globular clusters (to ~10 effective radii) in two dimensions around the survey galaxies. The science goals are to map out halo substructure, mass, angular momentum, metallicity gradients, orbital structure, and the distribution of dark matter. These fundamental characteristics provide important clues about the assembly histories of galaxies.
The survey is a key project of the Study of the Astrophysics of Globular Cluster in Extragalactic Systems (SAGES) network.
2500 Globular Cluster Velocities!
Using median-resolution spectra and wide-field imaging, we have studied the kinematics of over 2500 globular clusters in twelve galaxies, nine of which were never studied before. We have been able to the investigate the kinematics of the blue and red globular clusters separately, finding that these two components behave differently in some, but not all, galaxies.
Globular cluster system kinematics and substructure in NGC 4365
We analyse the kinematics of the globular cluster system of NGC 4365 and find that the three globular cluster subpopulations have different kinematic features. When compared with the stellar orientation and kinematics, the kinematics of each subpopulation constrain the possible formation scenarios of NGC 4365 and its globular cluster system.
Globular Cluster Metallicity Bimodality Confirmed
We have used the strength of the calcium triplet to measure the metallicity of over 900 globular cluster, the largest sample of spectroscopic globular cluster metallicities yet assembled. This allows us to show that the metallicity distributions of globular cluster around six galaxies is bimodal indicating that the ubiquitous colour bimodality of globular clusters is caused by metallicity bimodality.