TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2015 SUBJECT: GRB030329: optical spectroscopy with the TNG DATE: 03/03/30 05:56:08 GMT FROM: Angelo Antonelli at Obs. Astro. di Roma R. Della Ceca, T. Maccacaro (INAF-OABrera), D. Fugazza, M. Pedani, M. Cecconi (TNG), F. Fiore, L.A. Antonelli (INAF-OAR), S. Covino (INAF-OABrera), E. Pian (INAF-OATs), N. Masetti (IASF-CNR) report: "Starting on March 30 2003 00:43:40 UT we have obtained low resolution (R~1000) spectra of the optical afterglow of GRB030329 (Peterson & Price GCN #1985, Torii, GCN #1986) using DOLORES at TNG. Observations consisted of two exposures of 15 min each the second obtained at 2.75hh after the first, and cover the full spectral range 3800-8000 Angstrom, in relatively good seeing conditions (1.5"). At the time of the observations the afterglow magnitude was R~15-16 (e.g. Martini et al. GCN #2012). A preliminary analysis of the spectra reveals no strong absorption features. A more detailed analysis is needed to search for faint absorption lines. A faint emission line at 5846 Angstrom (see Martini et al. GCN# 2013) is present in the later spectra, when the afterglow emission was less strong. If this is [OII] emission from the host galaxy, then the redshift is z=0.568. We detect a strong spectral variability between the first spectrum, when the afterglow was extremely blue, and the second spectrum, obtained starting from 03:25:35 UT. We are particularly grateful to the TNG staff for their remarkable support to these observations. This message may be cited."