GCN Circular 1953
Subject
VLT/FORS2 spectra of GRB 030323
Date
2003-03-25T06:02:12Z (21 years ago)
From
Paul Vreeswijk at ESO <pvreeswi@eso.org>
Paul Vreeswijk (ESO), Ralph Wijers, Evert Rol (U. of Amsterdam), and
Jens Hjorth (U. of Copenhagen) report for the GRACE collaboration:
The field of GRB 030323 (HETE trigger 2640) was observed last night
(March 24/25) in spectroscopic mode with FORS2 at unit-4 of ESO's VLT
at Paranal, Chile. The total exposure time was 1 hour in the 300V and
300I grisms, covering approximately 4000-9300 A with a resolution of
about 12 A. The slit (1" wide) was positioned to cover the position of
the presumed afterglow (Gilmore, Kilmartin & Henden, GCN 1949; see
also GCN 1952), as well as a nearby reference object.
Preliminary reduction of the 300V spectra of the candidate afterglow
shows very strong absorption over the range 516-545 nm, presumably a
complex of Ly alpha clouds around z = 3.3-3.4. The detection of
numerous narrow lines is consistent with this interpretation: we can
identify these with metal-absorption lines (SiII, OI, CII, SiIV, CIV,
AlII) at a redshift of z = 3.372. These Ly alpha and metal-absorption
lines probably originate in the host galaxy of GRB 030323.
We appreciate the assistance of the ESO staff at Paranal; in
particular of Thomas Szeifert and Olivier Marco.