TITLE:   GCN CIRCULAR
NUMBER:  6335
SUBJECT: GRB 070411: BART early limit
DATE:    07/04/20 15:30:56 GMT
FROM:    Martin Jelinek at Inst.Astrophys.Andalucia,Granada  <mates@iaa.es>

Jan Strobl  (ASU  Ondrejov),  Martin Jelinek  (IAA
CSIC  Granada),  Martin Nekola,  Filip Munz,  Rene
Hudec (ASU) and Petr Kubanek (IAA, U. Valencia)

report

The  robotic telescope  BART in  Ondrejov followed
automatically the  GRB 070411  (Moretti et al. GCN
6267), with  the first exposure starting 55.7s af-
ter  the GRB  trigger (15.9s  after receiving  the
message).

The beginning of the (unfiltered) optical observa-
tion is simultaneous to  the second gamma-ray peak
of this ~100s long GRB (Markwardt et al. GCN6274).

The  optical transient  (Moretti et al.  GCN 6267,
Kann et al. GCN6268)  was not detected, giving the
following limits:

start   end     limit	note
-----------------------------
55.7s   85.7s   R>15.4  30s, simultaneous to gamma
55.7s  167.9s   R>16.0  3x30s

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