GCN Circular 12777
Subject
GRB 111229A: Gemini-South Redshift
Date
2011-12-30T02:32:04Z (12 years ago)
From
Antonino Cucchiara at LBNL <acucchiara@lbl.gov>
A. Cucchiara (UCSC/UCO Lick), A. J. Levan (U. Warwick),
and N. Tanvir (U. Leicester) report:
On December 30.05 UT (157 minutes after the BAT trigger)
we observed the field of GRB 111229A (Lien et al., GCN 12774)
using GMOS-South on the Gemini-South 8-m telescope.
An optical afterglow is detected at a position reported by
Nicuesa Guelbenzu et al. (GCN 12775).
Subsequent spectroscopic observation of the optical afterglow of
GRB 111229A (range 5900-10080 Angstroms) reveals several absorption
features, including FeII2586,2600, MnII2606, MgII2796,2803
and MgII2853 at a common redshift of 1.3805.
We therefore suggest this to be the redshift of GRB 111229A.
We thank the Gemini staff for performing this observation,
in particular Pascale Hibon.