TITLE:   GCN CIRCULAR
NUMBER:  8448
SUBJECT: GRB 081029: Redshift Confirmation from Gemini-South
DATE:    08/10/29 14:43:19 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (Penn State), S. B. Cenko  (Berkeley) and E. Berger
(Harvard) report on behalf of a larger collaboration:

Starting at 07:04 UT on 2008 November 29 (T0+5h) we observed the optical
counterpart of GRB 081029 (Sakamoto et al., GCN 8435, Rykoff  et al.,
GCN 8436) using Gemini-South with the GMOS-South spectrograph (R~1600).
We acquired 2x900s spectra covering the wavelength range 4000A-8000A.

We detect a damped Lyman-alpha system (DLA) at redshift z=3.847.

We also detect several metal absorption features which we interpret as
SiIV(1393,1402), SiII1526 and 1260, SiII*1264, CI1560, CII1334, CII*1335,
CIV(1548,1550), FeII1608, NV(1238,1242) at the same redshift.

In combination with the strong metal absorption features, the detection of
a DLA at z=3.847 confirms that this is the redshift of GRB 081029 and its
host galaxy.

Our results are consistent with those of D'Elia et al. (GCN 8438).

We thank the Gemini staff, in particular Rodrigo Damele, for conducting
these observations.