TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2117 SUBJECT: GRB030329: HET spectroscopic monitoring DATE: 03/04/08 03:37:04 GMT FROM: Mike Eracleous at PSU, Astro.Dept. Mike Eracleous (Penn State), Brad Schaefer, and Chris Gerardy (U. Texas) on behalf of the Hobby-Eberly Telescope GRB followup team report: We have obtained several spectra (410-900 nm, resolution 1.6 nm) of the optical counterpart of GRB030329 (Peterson & Price, GCN 1985; Torii: GCN 1986) with the Hobby-Eberly Telescope and Marcario Low-Resolution spectrograph. Our spectra of March 31, April 2, and April 5 (UT) show the following evolution of the spectral properties: (a) the equivalent widths of the [O III] and H-alpha emission lines is increasing in a manner consistent with a constant line flux and a decline of the continuum, and (b) the spectrum of April 5 (UT) shows evidence of a broad feature underlying the [O III] lines, similar tresembling that reported by Matheson et al. (GCN 2107), who interpret it as due to an emerging SN spectrum. However, the contrast of this feature in our spectrum is not as high as in the spectrum of Matheson et al. (taken a day later than ours). As a consequence, we cannot rule out alternative interpretations, such as the emergence of a host galaxy spectrum that manifests itself as a break in the power-law continuum. Analysis of more recent spectra is under way to clarify this issue. Using the [O II] and H-alpha emission line fluxes of Caldwell et al. (GCN 2053), we estimate luminosities of 1x10^40 and 4x10^40 erg/s, respectively (for z=0.168, i.e., a luminosity distance of 880 Mpc), and infer star formation rates of 0.15 and 0.32 solar masses/yr (following Kennicutt 1998, ARAA, 36, 189). The upper limit on the host galaxy from historical images reported by Wood-Vasey et al. (GCN 1998; R > 22.28) implies a limit on the absolute magnitude of M_R > -17.4, which is comparable to that of the LMC. The [OIII]/H-beta ratio of 2.7 (Caldwell et al.; GCN 2053) corresponds to an LMC-like faint starburst galaxy (Ho, et al. 1997, ApJ, 487, 579, Figure 6; Hunter & Gallagher, 1997, ApJ, 475, 65; Hunter et al. 2001 ApJ, 553, 121), while the H-alpha luminosity is characteristic of starburst galaxies (Ho. et al. Figure 2). High-dispersion spectroscopy of these narrow lines may give more information on the nature of star formation in the host galaxy.