TITLE: GCN CIRCULAR NUMBER: 7006 SUBJECT: GRB071020, optical upper limit DATE: 07/10/26 12:37:21 GMT FROM: Eri Sonoda at U of Miyazaki/Japan R. Hara, E.Sonoda, H.hayasi, N.Ohmori, K.Kono H. Tanaka, M.Yamauchi (University of Miyazaki) We have observed the field covering the error circle of GRB071020 (GCN 6954, J. Tueller et al.) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 15:29:35 UT, ~507 min. after the Swift trigger time. We have compared our data of 30 sec exposures with the USNO-A2.0 catalog,there is no new source at the reported position (GCN 6948, B.E.Schaefer et al. GCN 6949, S.T.Holland et al. GCN 6978, P. Chandra et al.) the upper limits are as follows: -------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 15:31:27 15:31:57 1 ~16.5 15:31:27 16:24:39 20 ~17.0 ---------------------------------------------------------------