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 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 This message may be cited