GCN Circular 6202
Subject
GRB 070306: possible emission-line redshift
Event
Date
2007-03-12T20:37:34Z (19 years ago)
From
Andreas O. Jaunsen at ITA/U Oslo <ajaunsen@astro.uio.no>
A.O. Jaunsen (Univ. Oslo), C.C. Thoene, J.P.U. Fynbo, J. Hjorth (DARK/
NBI),
P. Vreeswijk (ESO) report on behalf of a larger collaboration.
We observed the field of GRB 070306 (Pandey et al., GCN 6169 & GCN
Report 38.1)
with the ESO/VLT equipped with FORS2. Observations started on 2007
Mar 08.11 UT
(about 34 hr after the GRB) and three 1800-s spectra were acquired
with the
300V grism covering a wavelength range of 3500-9500A.
The spectrum consists of a largely featureless continuum from about
4000-9400A
with the exception of an apparent emission line at ~9310A. The
emission-line
is very close to the prominent telluric skyline at 9313A, but is seen
in each
of the three individual spectra. The lack of other detected lines in the
observed wavelength range suggests that the emission line is due to
[O II] at
a red-shift of z=1.497. It should be cautioned, however, that this
host galaxy
appears to be highly reddened (as already noted by Rol et al., GCN
6174), which
could have an unforeseen suppression-effect on the bluer part of the
spectrum.
We acknowledge the excellent support from the ESO/Paranal staff.