[vsnet-grb-info 2755] GRB 060124: Keck Absorption Redshift

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4592
SUBJECT: GRB 060124: Keck Absorption Redshift
DATE:    06/01/25 09:40:11 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko (Caltech), E. Berger (Carnegie Observatories) and J. Cohen
(Caltech) report on behalf of a larger collaboration:

"We obtained two 1800 sec spectra of GRB 060124 (Holland et al., GCN 4570)
with the Echellette Spectrograph and Imager (ESI) on the Keck 10-m
telescope starting on 2006 Jan. 25.23 UT.  We detect the broad absorption
feature detected by Mirabal and Halpern (GCN 4591), which is clearly a
doublet, and identify it as CIV 1548,1550 at z=2.297.  We also detect the
MgII 2796,2803 at the same redshift.  At this redshift and given a
fluence of about 7e-6 erg/cm^2 (Fenimore et al., GCN 4586) we find an
isotropic-equivalent gamma-ray energy of 8.9e52 erg."