GCN Circular 8300
Subject
GRB080928: Gemini-South Absorption Redshift
Date
2008-09-29T15:31:33Z (16 years ago)
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 06:54 UT on 2008 September 29 (T0+16h) we observed the optical
counterpart of GRB 080928 (Sakamoto et al., GCN 8292, Rykoff et al.,
GCN 8293)
using Gemini-South with the GMOS-South spectrograph (R~1200).
We acquired 2x900s spectra which covered the wavelength range 4000A-8000A.
Our spectrum shows a flux cut-off blueward of 4500A indicating a likely DLA
associated with the GRB host galaxy, consistent with a redshift of z ~ 2.6.
We also identify multiple metal absorption features including FeII(2249),
FeII(2260), SiIV(1393), SiIV(1402), CIV(1548), CIV(1550), NiII(1741) and
NiII(1751) at a common redshift of z = 2.49.
Therefore we conclude that GRB080928 occurred in a possible DLA galaxy
at z = 2.49.
We thank the Gemini staff for conducting these observations.
[GCN OPS NOTE(29sep08): Per author's request, the affiliation for EB
was corrected to Harvard.]