Recent high-resolution observations with the Hubble Space Telescope ( HST ) reveal that star clusters of extraordinary luminosity and compactness are commonly found in a variety of starburst systems .
There has been much speculation that these clusters represent present-day analogs of young globular clusters .
Using the HIRES echelle spectrograph on the Keck 10 m telescope , we obtained high-dispersion optical spectra of one of the “ super star clusters ” ( cluster “ A ” ) in the nearby dwarf galaxy NGC 1569 .
The size of the cluster is known from published HST images .
The line-of-sight velocity dispersion ( \sigma _ { * } = 15.7 \pm 1.5 \kms ) has been measured from a cross-correlation analysis of its integrated spectrum at visual wavelengths .
If the cluster is gravitationally bound and the velocities are isotropic , application of the virial theorem implies that the cluster has a total stellar mass of ( 3.3 \pm 0.5 ) \e 5 \solmass .
This object ’ s mass , mass density , and probable mass-to-light ratio after aging 10–15 Gyr are fully consistent with the typical values of Galactic globular clusters .
Our result strongly suggests that at least some of the luminous , compact , young star clusters being discovered with HST will indeed evolve into normal globular clusters of the type seen in the Milky Way .