Properties of the Z=2.73 galaxy, MS1512-cB58

MS1512-cB58 is an z=2.73 galaxy whose apparent brightness is amplified by30 -50X due to gravitationally lensing. The restframe far-UV spectrum of cB58 that was obtained by Keck-I/LRIS is `one of the best ultraviolet spectra of a starburst galaxy obtained at any redshift' (Pettini et al., 2000). We ha ve analyzed and modeled the spectrum of this galaxy in order to learn the p roperties of high-redshift galaxies. We find that our model spectrum is a n ear match to the observed spectrum of cB58 if the galaxy has a SMC-like met allicity, and has a Salpeter IMF extending up to similar to 100 M. The spec trum of cB58 also shows many absorption lines formed in a giant, expanding gas shell surrounding the star-forming complex. We show preliminary finding s of the properties of the giant HII region based on our CLOUDSPEC model.