TITLE: GCN CIRCULAR NUMBER: 27473 SUBJECT: GRB 200325B: Optical upper limit DATE: 20/04/02 10:08:41 GMT FROM: Amit Kumar at ARIES, India TITLE: GCN CIRCULAR NUMBER: 27472 SUBJECT: GRB 200325B: Optical upper limit DATE: 20/04/02 9:44:53 GMT FROM: Amit Kumar at ARIES, India A. Kumar (ARIES), A. Aryan (ARIES), S. B. Pandey (ARIES), R. Gupta (ARIES), A. Ghosh (ARIES), Dimple (ARIES), and K. Misra (ARIES) report: We observed the optical afterglow field of the Fermi GRB 200325B (Fermi GBM team, GCN 27441, Lipunov et al., GCN 27446) with 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (India), from 2020-03-30 UT 19:37:08 to 2020-03-30 UT 20:59:28. We observed 16 frames each of 300 seconds in Bessell I filter. No new optical source was detected within the Swift XRT enhanced error circle in any individual as well as stacked frame. The 3-sigma upper limit is as follows: T_start-T0 (days) Start Date (UTC) End Date (UTC) Filter 3-sigma upper limit (mag) --------------------------------------------------------------------------------------------------------------- 5.21 2020-03-30 19:37:08 2020-03-30 20:59:28 I >23.2 Photometry is done based on the standard star PB 2256 and USNO-B1.0 catalog. The quoted magnitude is not corrected for Galactic extinction.