Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 13441

GRB 120711A Gemini-S likely redshift
2012-07-11T12:46:35Z (12 years ago)
Nial Tanvir at U.Leicester <>
N. R. Tanvir, K. Wiersema (U. Leicester), A. J. Levan (U. Warwick),
D. Fox (Penn State), A. Fruchter (STScI) and D. Krogsrud (Gemini)
report on behalf of a larger collaboration:

We observed the afterglow of GRB 120711A (Gotz et al. GCN 12434;
Lacluyze et al. GCN 12430) using the GMOS-S spectrograph on Gemini-South.

Observations began at 2012-7-11 10:08 UT, about 7.5 hr post-burst.
The data were obtained at high air-mass and on the boundary of twilight,
so the signal-to-noise is rather poor.  Nevertheless,
in the spectrum we identify lines of MgII (2797/2804A) and
FeII (2374/2383/2587/2600A) at a common redshift of z=1.405.

This therefore provides a robust lower-limit to the redshift of the GRB.
Furthermore, given the lack of other absorption features, in particular
any matching a redshift z~3 (Elliott et al. GCN 13438), we tentatively
identify z=1.405 as the most likely GRB redshift.
Looking for U.S. government information and services? Visit