GCN Circular 5715
Subject
GRB 061007: Magellan Spectroscopy
Date
2006-10-08T07:51:33Z (18 years ago)
From
Hsiao-Wen Chen at U Chicago <hchen@oddjob.uchicago.edu>
David Osip (Las Campanas Observatory), H.-W. Chen (U Chicago), and J. X. Prochaska (UCO/Lick Observatory) report on behalf of a larger collaboration:
"We observed the afterglow of GRB061007 reported by Rykoff & Rujopakarn (GCN
5706) and confirmed by Mundel et al. (GCN5708) and Bersier et al., using the
LDSS3 with a 0.75-arcsec slit on the Magellan Clay telescope at the Las
Campanas Observatory. The observations started at 03:54:00 UT on October 8,
2006, ~ 18 hours after the inital Swift/BAT trigger, and were carried out
under a mean seeing condition of 0.75 arcsec in a sequence of five 1200-sec
exposures. The final stacked spectrum covers the spectral range from 3900
Ang to 6500 Ang with a spectral resolution element of 2.4 Ang. In the
spectrum, we identify a strong MgII absorption system, accompanied with
FeII 2344 and 2600 transitions) at z=1.261. We consider this the likely
redshift of GRB061007, given the absence of a strong Lya feature (or any
other strong metal-line transitions) in our spectrum. We also report an
intervening MgII system at z=1.06.
Further analysis is underway.
This message may be cited."