TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5073 SUBJECT: GRB 060502B: AROMA refined photometric calibration DATE: 06/05/04 19:15:10 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U I.Takahashi, T.Uehara, K.Yoshida, A.Kobayashi, T.Koshiishi, K.Tanaka, Y.E.Nakagawa, S.Sugita, K.Yamaoka, A.Yoshida (AGU) report: After the previous report (GCN 5065), we carried out further photometric calibrations for the observations of the GRB 060502B field (Troja et al. GCN 5055, GCN 5059). We have taken 100 frames of R band image with 20s exposure each and photometric calibration was mede by every 20 frames by comparing with USNO A2.0 stars in the same field. The 3 sigma limiting magnitude of each combined image is as below. data set mean time time - burst[s] lim-mag R (3sigma) ====================================================== 1st 17:30:00 UT 319 16.12 +/-0.16 2nd 17:37:35 UT 774 16.26 +/-0.19 3rd 17:45:13 UT 1232 16.00 +/-0.05 4th 17:52:44 UT 1683 16.00 +/-0.02 5th 18:00:13 UT 2132 16.30 +/-0.02