GCN Circular 10100
Subject
GRB 091029: Gemini-South Redshift
Date
2009-10-29T07:49:19Z (15 years ago)
From
Ryan Chornock at UC Berkeley <chornock@astro.berkeley.edu>
R. Chornock, D. A. Perley, and B. E. Cobb (UC Berkeley) report on behalf of a
larger collaboration:
We obtained optical spectra of the afterglow of GRB 091029 (Grupe et al., GCN
10097; Filgas et al., GCN 10098; LaCluyze et al., GCN 10099) using GMOS on
Gemini-South. Our spectra cover the wavelength range of 3900-8100 angstroms
with the R400 grating. Our first 600s exposure, starting at 06:06 UT on Oct. 29
(2.2 hr after the BAT trigger) reveals absorption lines from Lyman-alpha, C II,
C IV, Si II, and Si IV at a common redshift of 2.752, which we identify as
the redshift of the GRB. The afterglow is still quite bright (R~17.8 mag at
t=2.02 hr) in the acquisition image.
We would like to thank German Gimeno and the Gemini staff for their assistance.