T. A. Fatkhullin, A. S. Moskvitin, V. V. Sokolov (SAO-RAS, Nizhnij Arkhyz),
A. S. Pozanenko (IKI, Moscow), A. de Ugarte Postigo (ESO, Santiago), M.
Jel�nek, J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC Granada), on
behalf of a larger collaboration, report:
"Following the detection of GRB 080328 by Swift (Perri et al. GCNC
7525), we have obtained BVRI imaging and spectroscopy (3800-7500 A) with
the 6.0m BTA SAO-RAS telescope starting on Mar 28.76 UT (i.e. 12.4 hr
after the onset of the event). A faint optical source (with R about
22.5) consistent with the UVOT position (Ward et al. GCNC 7530) is
detected in all frames, thus implying an upper limit of about 2.5 for
the GRB 080328 redshift. Its brightness is not consistent with the
extrapolation of the early decay reported by Guidorzi et al. (GCNC 7526)
indicating significant contribution of the reverse shock emission in the
FTN data. Our BTA spectrum (2 x 900s) shows only a faint continuum and
nothing conclusive can be reported (except the non-existence of strong
emission lines arising from an underlying host galaxy)."
This message can be quoted.
[GCN OPS NOTE(29mar08): Per author's request, 3 typos were fixed
in the Fatkhullin, Moskvitin and Pozanenko names.]