TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  807
SUBJECT: Spectroscopic Redshift of GRB 000926
DATE:    00/09/28 14:03:26 GMT
FROM:    Jens Hjorth at U.Copenhagen  <jens@astro.ku.dk>

Spectroscopic Redshift of GRB 000926


J. P. U. Fynbo, P. Moller (ESO), T. Dall (NOT and U. of Aarhus), 
H. Pedersen, B. L. Jensen, J. Hjorth (U. of Copenhagen) and J. Gorosabel 
(DSRI, Copenhagen) report on behalf of a larger European GRB Collaboration:

"We have analysed the spectrum of the optical afterglow of GRB 000926 
(GCN #803, GCN #804) reported by Dall et al. (GCN #804). The spectrum
was obtained 22.2 hours after the burst with ALFOSC at the Nordic Optical
Telescope and covered the wavelength range from the atmospheric cut-off
to 8800 A. We find two significant absorption systems: One at z = 1.378 
(based on Al II 1670, Fe II 2344, Fe II 2374, Fe II 2382, Fe II 2586) and 
one at z = 2.066 (based on Ly alpha 1215, Si IV 1393, Si IV 1402, C IV 
1548/1550, Fe II 1608, Al II 1670). The redshift of GRB 000926 is likely 
to be z = 2.066 due to the high column density of this absorption system. 
In an Omega_m = 0.3, Omega_Lambda = 0.7, H_0 = 65 km s^-1 Mpc^-1 cosmology 
the 25 - 100 keV fluence of 2.2 10^-5 erg cm^-2 (Hurley et al. GCN #801, 
GCN #802) corresponds to an isotropic energy release of 2.6 10^53 erg".