We have obtained K -band Multi-Object Spectrograph ( KMOS ) near-IR spectroscopy for 14 red supergiant stars ( RSGs ) in the young massive star cluster NGC 2100 in the Large Magellanic Cloud ( LMC ) .
Stellar parameters including metallicity are estimated using the J -band analysis technique , which has been rigorously tested in the Local Universe .
We find an average metallicity for NGC 2100 of [ Z ] = - 0.43 \pm 0.10 dex , in good agreement with estimates from the literature for the LMC .
Comparing our results in NGC 2100 with those for a Galactic cluster ( at Solar-like metallicity ) with a similar mass and age we find no significant difference in the location of RSGs in the Hertzsprung–Russell diagram .
We combine the observed KMOS spectra to form a simulated integrated-light cluster spectrum and show that , by analysing this spectrum as a single RSG , the results are consistent with the average properties of the cluster .
Radial velocities are estimated for the targets and the dynamical properties are estimated for the first time within this cluster .
The data are consistent with a flat velocity dispersion profile , and with an upper limit of 3.9 \mbox { km s } ^ { -1 } , at the 95 % confidence level , for the velocity dispersion of the cluster .
However , the intrinsic velocity dispersion is unresolved and could , therefore , be significantly smaller than the upper limit reported here .
An upper limit on the dynamical mass of the cluster is derived as M _ { dyn } \leq 15.2 \times 10 ^ { 4 } M _ { \odot } assuming virial equilibrium .