Using the AAOmega instrument of the Anglo-Australian Telescope, we have obtained medium-resolution near-infrared spectra of 10,500 stars in 2° fields centered on the galactic globular clusters 47 Tuc, NGC 288, M12, M30, and M55. Radial velocities and equivalent widths of the infrared Ca II triplet lines have been determined to constrain cluster membership, which in turn has been used to study the angular extent of the clusters. From the analysis of 140-1000 member stars in each cluster, we do not find extended structures that go beyond the tidal radii. For three cluster we estimate a 1% upper limit of extratidal red giant branch stars. We detect systemic rotation in 47 Tue and M55.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Galaxy: halo
- Galaxy: kinematics and dynamics
- Galaxy: structure
- Globular clusters: general