TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3732 SUBJECT: GRB 050730: Preliminary Analysis of MIKE Spectrum DATE: 05/08/02 06:00:34 GMT FROM: Jason Prochaska at UCO/Lick Obs J. X. Prochaska (UCO/Lick), H.-W. Chen (MIT), J. S. Bloom (UCB), J. O'Meara (MIT), S. M. Burles (MIT), I. Thompson (OCIW) report on behalf of the GRAASP collaboration: "We have performed preliminary analysis of our MIKE spectrum of the afterglow of GRB 050730. A profile fit to the Lya and Lyb absorption lines of the sightline through the host galaxy gives N(HI) = 22.15 +/- 0.05. The simple and narrow metal-line profiles give a redshift z=3.96855 +/- 0.00005. We estimate a neutral gas metallicity of S/H ~ 1/100 solar which is lower than the mean metallicity of damped Lya system at this redshift. More strikingly, we identify fine-structure lines of SiII*, OI*, OI**, and FeII*, the majority of which are saturated. Also, we identify absorption features near 6150A which we interpret as the NV absorption doublet. Finally, we identify an intervening damped Lya system at z=3.5650 +/- 0.0001 with log N(HI)= 20.30 +/- 0.15 and low metallicity as well as a z=1.773 MgII absorber. A full analysis is underway. Figures can be found at this following site: http://www.graasp.org/Data/index.html