TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  989
SUBJECT: GRB 010222: Keck Spectroscopy
DATE:    01/02/25 06:52:49 GMT
FROM:    Josh Bloom at CIT  <jsb@astro.caltech.edu>

GRB 010222: Keck Spectroscopy

J. S. Bloom, S. G. Djorgovski (Caltech), J. P. Halpern (Columbia), S. R.
Kulkarni, T. J. Galama, P. A. Price, S. M. Castro (Caltech) report on
behalf of the larger Caltech-NRAO-CARA GRB Collaboration:

"We obtained two epochs of optical spectroscopy of the transient of GRB
010222 (GCN #959; #961) using the dual-CCD Low-Resolution Imaging
Spectrometer (LRIS; Oke et al. 1995) on the Keck I 10-m telescope on Mauna
Kea, Hawaii.  We confirm the redshifts of the two absorption systems
previously reported by Garnavich et al. (GCN #965) and Jha et al. (GCN
#974).  We find an additional absorption system at z=0.928 as well other
as yet unidentified absorption lines.

The first set of spectra were taken by R. -P. Kudritzki and F. Bresolin on
22.66 Feb 2001 UT using the 300/5000 grism (blue side) and 400/8500
grating (red side) with a total integration time of 1800s on-source in
both CCDs.  The second set of spectra were taken by H. Spinrad, D. Stern,
A. Dey, A. Bunker, and S. Dawson on 23.66 Feb 2001 UT with the identical
setup and integration time as the first epoch.  

A preliminary comparison of absorption-line strengths reveals no
significant variation of the equivalent widths between the two epochs."

We thank A. A. Henden for providing an image of the GRB field which
facilitated the first epoch of spectroscopy.

This message may be cited.