TITLE: GCN CIRCULAR NUMBER: 39901 SUBJECT: GRB 250322A: GRANDMA/TNOT optical upper limits DATE: 25/03/28 09:01:10 GMT FROM: duverne@apc.in2p3.fr
E. Elhosseiny (NRIAG), N. Kochiashvili (AbAO), O. Pyshna (Caltech), Haichang Zhu (THU), A. Iskandar(XAO), Xiaofeng Wang (THU), Letian Wang (XAO) C. Andrade (UMN), S. Antier (OCA/IJCLAB), M. Coughlin (UMN), P-A. Duverne (APC), N. Guessoum (AUS), P. Hello (IJCLAB), S. Karpov (FZU), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu) on behalf of the GRANDMA and Kilonova-Catcher collaborations:
The field of GRB 250322A (Gupta et al., GCN 39835, Goad et al. GCN 39841, Perri et al. GCN 39855, Sadaula et al. GCN 39867) has been imaged with the 80~cm Tsinghua-Nanshan Optical Telescope (TNOT) located at Nanshan Station of Xinjiang Astronomy observatory 1.1h post trigger with the r' filter for a total exposure of 100s.
We do not detect any new source at the enhanced Swift-XRT position (Goad et al. GCN 39841) down to r<21.2 AB mag (5-sigma) calibrated with nearby Pan-STARRS stars and without Galactic extinction correction. All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2025 Acta Polytechnica, 65(1), 50-64).
We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023).
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
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