Super Star Clusters in M82: Young Globular Clusters?
Abstract
Using high-resolution (R ~ 22,000) near-infrared (1.51 μ m <λ < 1.75 μ m) spectra from Keck Observatory, we measure the kinematic masses of two super star clusters (SSCs) in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives stellar velocity dispersions of 16.2 +/- 0.8 km/s for cluster MGG-9 and 11.3 +/- 0.7 km/s for cluster MGG-11. The cluster spectra are dominated by the light of red supergiants, and correlate most closely with a template star of spectral type M0Iab. King model fits to the observed profiles of the clusters in archival HST/NICMOS images give half-light radii of 2.6 +/- 0.2 pc for MGG-9 and 1.15 +/- 0.09 pc for MGG-11. Applying the Virial theorem, we determine masses of 1.6 +/- 0.3 x 106 Msun for MGG-9 and 3 +/- 1 x 105 Msun for MGG-11. The sizes, masses, velocity dispersions, profiles and ages of the clusters suggest that these SSCs may represent globular clusters forming in the present-day universe.
- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AAS...201.8103M