Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. I. Abundances and Velocities for a Sample of Clusters

TL;DR

This study presents the largest spectroscopic dataset of Small Magellanic Cloud clusters, measuring their velocities and metallicities to better understand their properties and distribution.

Contribution

It provides new, high-precision spectroscopic measurements of velocities and metallicities for 16 SMC clusters, covering a wide age range and improving spatial coverage.

Findings

Mean cluster velocities determined with ~2.7 km/s accuracy

Cluster metallicities measured with 0.05 dex precision

Sample includes a diverse range of cluster ages and locations

Abstract

We have obtained near-infrared spectra covering the Ca II triplet lines for a number of stars associated with 16 SMC clusters using the VLT + FORS2. These data compose the largest available sample of SMC clusters with spectroscopically derived abundances and velocities. Our clusters span a wide range of ages and provide good areal coverage of the galaxy. Cluster members are selected using a combination of their positions relative to the cluster center as well as their abundances and radial velocities. We determine mean cluster velocities to typically 2.7 km/s and metallicities to 0.05 dex (random errors), from an average of 6.4 members per cluster. (continued in paper)