[vsnet-grb-info 2178] GRB 050922C: Absorption redshift from the Nordic Optical Telescope

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4017
SUBJECT: GRB 050922C: Absorption redshift from the Nordic Optical Telescope
DATE:    05/09/22 23:33:59 GMT
FROM:    Pall Jakobsson at Niels Bohr Inst  <pallja at astro.ku.dk>

Pall Jakobsson, Johan P. U. Fynbo, (DARK, NBI), Danka Paraficz,
John Telting (NOT, La Palma), Brian L. Jensen, Jens Hjorth and
Jose Maria Castro Ceron (DARK, NBI) report:

Using ALFOSC on the Nordic Optical Telescope (NOT) we have obtained
spectra of the afterglow of GRB 050922C (GCN#4013 Norris et al.
[Swift], GCN#4012 Rykoff et al. [ROTSE-III], GCN#4015
Jakobsson et al. [NOT]) on 2005, Sep 22.9 UT.

We find several absorption features, including strong Lyman-alpha,
OI+SiII, CII, SiIV, CIV, AlII and AlIII, corresponding to a redshift
of z = 2.17+-0.03 (based on a preliminary wavelength calibration).
There is additional strong absorption, possibly corresponding to
Lyman-alpha at z = 2.05+-0.03.