Radial velocities of five globular clusters obtained with AAOmega

TL;DR

This study used the AAOmega spectrograph to measure radial velocities and stellar parameters for over 10,000 stars in five globular clusters, revealing systemic rotation in most of them.

Contribution

It provides a large dataset of stellar velocities and parameters in five globular clusters, demonstrating the capability of AAOmega for detailed cluster kinematic studies.

Findings

Detected systemic rotation in four clusters

Measured radial velocities with 1 km/s precision

Estimated stellar parameters for thousands of stars

Abstract

Using the recently commissioned multi-object spectrograph AAOmega on the 3.9m AAT we have obtained medium-resolution near-infrared spectra for 10,500 stars in and around five southern globular clusters. The targets were 47 Tuc, M12, M30, M55 and NGC 288. We have measured radial velocities to +/- 1 km/s with the cross correlation method and estimated metallicity, effective temperature, surface gra vity and rotational velocity for each star by fitting synthetic model spectra. An analysis of the velocity maps and velocity dispersion of member stars revealed systemic rotation in four of the target clusters.