[AAVSO-HEN] GRB 080605: VLT redshift

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TITLE:   GCN CIRCULAR
NUMBER:  7832
SUBJECT: GRB 080605: VLT redshift
DATE:    08/06/06 03:56:15 GMT
FROM:    Pall Jakobsson at U Hertfordshire  <P.Jakobsson at herts.ac.uk>

Pall Jakobsson (U. Hertfordshire), Paul M. Vreeswijk,
Dong Xu and Christina C. Thoene (DARK, NBI) report on behalf 
of a larger collaboration:

Using FORS2 on the Very Large Telescope, we have obtained
a 10 min spectrum (grism 300V) of the optical afterglow of
GRB 080605 (Sbarufatti et al., GCN 7828). The acquisition 
image shows it to have R = 20.4 on June 6.063 (1.7 hours
post burst).

A firm upper limit of z < 2.1 can be placed on the redshift
of GRB 080605 from the lack of Ly-alpha forest lines in the
spectrum of the afterglow.

The spectrum is rich in absorption features, including Si II,
C IV, Al II, Al III, Zn II, Fe II, Mg II and Mg I, corresponding 
to a redshift of z = 1.6398 +/- 0.0006.

We thank the Paranal staff for excellent support, especially
Linda Schmidtobreick.