2 MICRON SPECTROSCOPY OF GALACTIC AND M31 GLOBULAR-CLUSTERS

Near-infrared spectroscopic observations, covering the wavelength intervals 1.5-1.8 μm and 2.0-2.4 μm, have been obtained of a small sample of Galactic and luminous M31 globular clusters. The strongest features in the spectra are absorption bands of CO and CN. The Δν= 2 CO bands in the mean M31 cluster spectrum are stronger than those in the Galactic metal-rich cluster NGC 6316, but similar in strength to those in NGC 6304. However, the CN bands in the mean M31 spectrum appear to be substantially stronger than those in Galactic globular clusters. Consequently, it is concluded that the near-infrared properties of at least some luminous M31 clusters are dominated by spectroscopically peculiar red giants.