[vsnet-grb-info 6746] GRB 081008: Gemini-South Absorption Redshiftt

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8346
SUBJECT: GRB 081008: Gemini-South Absorption Redshiftt
DATE:    08/10/09 04:15:43 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara at 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 00:20 UT on 2008 October 9 (T0+5h) we observed the optical
counterpart of GRB 081008 (Racusin et al., GCN 8344, Rykoff  et al.,
GCN 83433) using Gemini-South with the GMOS-South spectrograph (R~1600).
We acquired 2x900s spectra covering the wavelength range 3800A-6700A.

We clearly detect several metal absorption features which we interpret as
SiIV(1393,1402), SiII1526, SiII*1816, CIV(1548,1550), FeII1608, AlII1670,
NiII1703, AlIII(1854,1862), MgI2026 at the common redshift of z = 1.967.

The absorption system identified by D'Avanzo et al. (GCN 8345) can be
explained by the CIV and SiII/SiII* doublets at this redshift.

We thank the Gemini staff for conducting these observations.