TITLE: GCN CIRCULAR NUMBER: 6202 SUBJECT: GRB 070306: possible emission-line redshift DATE: 07/03/12 20:37:34 GMT FROM: Andreas O. Jaunsen at ITA/U Oslo A.O. Jaunsen (Univ. Oslo), C.C. Thoene, J.P.U. Fynbo, J. Hjorth (DARK/ NBI), P. Vreeswijk (ESO) report on behalf of a larger collaboration. We observed the field of GRB 070306 (Pandey et al., GCN 6169 & GCN Report 38.1) with the ESO/VLT equipped with FORS2. Observations started on 2007 Mar 08.11 UT (about 34 hr after the GRB) and three 1800-s spectra were acquired with the 300V grism covering a wavelength range of 3500-9500A. The spectrum consists of a largely featureless continuum from about 4000-9400A with the exception of an apparent emission line at ~9310A. The emission-line is very close to the prominent telluric skyline at 9313A, but is seen in each of the three individual spectra. The lack of other detected lines in the observed wavelength range suggests that the emission line is due to [O II] at a red-shift of z=1.497. It should be cautioned, however, that this host galaxy appears to be highly reddened (as already noted by Rol et al., GCN 6174), which could have an unforeseen suppression-effect on the bluer part of the spectrum. We acknowledge the excellent support from the ESO/Paranal staff.