GCN Circular 1635
Subject
GRB 021004: optical spectroscopy on Oct 11
Date
2002-10-14T19:12:38Z (22 years ago)
Edited On
2024-11-18T09:53:21Z (a month ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
A. J. Castro-Tirado, E. Pérez, J. Gorosabel (IAA-CSIC,
Granada), J. M. Castro Cerón (ROA, San Fernando),
M. Andersen (AIP, Potsdam), J. Hjorth (Univ. of Copenhagen),
E. Rol, R. Wijers (Univ. of Amsterdam), A. Fruchter
(STScI, Baltimore), S. Klose (TLS, Tautenburg),
J. Greiner (MPE, Garching) and E. Pian (OAT-INAF, Trieste)
on behalf of the GRACE Collaboration
report:
"We have obtained a 7200-s spectrum with the FORS1
spectrograph at the ESO's 8.2-m VLT3 telescope at
Paranal on Oct 11.125-11.231 UT. The range is 3500-
5700 A with a resolution of about 1 A/pix.
We confirm the detection of the Ly-alpha (1215.7 A)
emission line plus the C IV (1548,2 A, 1550.8 A)
absorption line system at a redshift z = 2.327 (GCN
1605). The Al II (1670 A) absorption line (GCN 1618)
is detected as well at the same redshift.
We also detect another two absorption line systems at
z = 2.297 and z = 2.321 on the basis of C IV (1548,2 A,
1550.8 A) lines. The latter system is also detected in
Si IV (1393.8, 1402.8). These two systems are consistent
with those reported by Salamanca et al. (GCN 1611) and
Savaglio et al. (GCN 1633).
The flux of the Ly-alpha line (1.9e-16 erg/cm2/s/A) is
comparable with the one measured by Keck (GCN 1620),
i.e. the Lyman-alpha flux is constant and we conclude that
arises from the GRB 021004 host galaxy, at z = 2.327."
This message may be cited.