TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2031 SUBJECT: GRB030329 - near contemporaneous optical limits from CONCAM DATE: 03/03/30 21:34:26 GMT FROM: Avishay Gal-Yam at Tel Aviv U, Israel E. O. Ofek, A. Gal-Yam, Y. Lipkin, K. Sharon and E. Medezinski (Wise observatory, TAU) report: We searched for archival CONCAM (www.concam.net) images covering the trigger time of GRB 030329 (March 29, 11:37:14, Ricker et al. GCN 1997). This part of the night was covered by CONCAM units at Kitt Peak and Mount Wilson Observatories. Unfortunately, CONCAM images for that night from Mauna Kea Observatory in Hawaii are uavailable on the net. CONCAM images covering the exact time of the GRB trigger do not appear in the web archives of both sites (Kitt Peak and Mount Wilson). We were therefore limited to the analysis of images taken a few minutes before and after the GRB. We could not detect an OT to a conservative limiting magnitude of 3.5. The Kitt peak images are superior: four 180 s CONCAM images, taken at Mar 29, 11:29:57, 11:33:52, 11:41:46 and 11:45:42 UT were searched. The magnitude limit is shallow as the GRB location was near the horizon at Keat Peak. If the instantaneous optical display associated with GRB 030329 (z=0.1685, Greiner et al. GCN 2020) had been similar to that of GRB 990123 (z=1.6), which peaked above mag 9, then after appropriate scaling by the luminosity distance (for a flat Universe with omega=0.3, neglecting effects of extinction), we would expect GRB 030329 to be ~240 times brighter than GRB 990123. This means that an optical source with mag ~3 should have been apparent on contemporaneous CONCAM images.