TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4986
SUBJECT: Possible GRB060421: BART limits
DATE:    06/04/21 07:45:54 GMT
FROM:    Martin Jelinek at Inst.Astrophys.Andalucia,Granada  <mates@iaa.es>

Jan Strobl, Martin Topinka, Martin Nekola and René Hudec
(ASU Ondrejov, Czech Republic),
Petr Kubánek (ISDC Versoix, Swtzerland and ASU Ondrejov)
and Martin Jelínek (IAA Granada)

report

Robotic telescope BART located in Ondrejov observatory in
Czech Republic, followed the Swift trigger 206257 (Goad et al,
GCN 4985). The observation in fully automatic mode (under
control of RTS2), started 33.7s after the Swift trigger time.
We did not find any new optical source. Particularly we set
the following limits:

Tmean   Exp   limit   
44s     20s  B>14.2 
98.0s   20s  V>15.2
152s    20s  i>15.3
206s    20s  z>14.3
184s  8x45s  R>15.3

The magnitudes are calibrated against USNO-A2.0.