P.M. Vreeswijk, E. Rol (U. of Amsterdam), J. Hjorth (U. of
Copenhagen), C. Kouveliotou (USRA, NASA/MSFC), E. Pian, E. Palazzi
(ITESRE, Bologna), H. Pedersen (U. of Copenhagen), J. Gorosabel,
A. Castro-Tirado (LAEFF-INTA, Madrid) and J. Greiner (AIP, Potsdam)
report on behalf of a larger European collaboration:
At Dec. 18.17 UT, we took two 30-minute low resolution spectra of the
optical counterpart to GRB991216 (GCN #472) with the VLT-Antu
telescope at the European Southern Observatory (ESO, Chile). These
spectra roughly cover the wavelength range 400-900nm.
We detect several absorption features that we can identify with the
following lines: FeII(at 237.45nm, 238.28nm, 258.67nm and 260.02nm),
MgII(279.64nm/280.35nm) and MgI(285.30nm), assuming there exist three
absorption systems at the redshifts z=0.77, z=0.80 and z=1.02.
No clear emission features are detected.
We are planning to take more spectra around Dec. 19.2 UT, which should
allow us to verify these preliminary results.
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