TITLE: GCN CIRCULAR NUMBER: 45128 SUBJECT: GRB 260706A : GRANDMA Upper limits DATE: 26/07/09 17:52:30 GMT FROM: antier@ijclab.in2p3.fr K. Agabi (OCA), A. Simon (TShNU of Kyiv), L. Wyrzykowski (Uni. Warsaw/NCBJ), A. Guštin (UNG School of Science, GoChile), J. Hambsch (VVS, GEOS, BAV), S. Antier (IJCLAB), M. Pillas (IAP), L. Abe (OCA), T T. Guillot (OCA). X. Sheng (QUB), P. Gokuldass (ERAU), E. Elhosseiny (KAO), O. Sokoliuk (UKyiv), Y. Rajabov (UBAI), Z. Maksut NU), E. Jehin (U of Liège), M. Ferrais (U of Liège) on behalf of GRANDMA collaboration: We observed the field of GRB 260706A detected by SVOM/ECLAIRs (GCN 45089), SVOM/GRM and Fermi-GBM (GCN 45088) and its counterpart detected by EP-FXT (GCN 45097, GCN 45114). The observations started at 20:30:00 UTC on the 6 of July 2026, 4.3 post ECLAIRs T0 with ASTEP and last about 1 day in all the network. We didn't detect any optical counterpart at the EP location (and near by) with GRANDMA, using 0.4m GoT1 telescope of University of Nova Gorica hosted at El Sauce Observatory in Chile, 0.6m TRAPPIST-South, 14" telescope at Franz-Josef Hambsch's Remote Observatory Atacama Dessert (ROAD) in Chile, ASTEP-50cm at Concordia, 1m LCO-SAAO telescope in South Africa with observatory in multiple epochs and filters. We reported our upper limit in the public ACME service Skyportal/ICARE https://skyportal-icare.ijclab.in2p3.fr/source/GCN-260706_161221. To access, one simply needs to create an account using your ORCID id. Our upper limit are coherent with REM (GCN 45100), LCO-1m (GCN 45098), and SVOM/VT (GCN 45113). The data were reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Sloan filters were calibrated using the PanSTARRS DR1 catalog. Images obtained with the Johnson-Cousins filters were calibrated using the Gaia DR3 Synphot catalog. The observations are performed under the P7 campaign of GRANDMA to monitor SVOM alerts and LSST alerts from explosive fast transients filtered by BOOM/Babamul and FINK. 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). Astrophysics Center for Multimessenger studies in Europe is supported Skyportal/ICARE (contact camille.douzet@ijclab.in2p3.fr, skyportal.io). View this GCN Circular online at https://gcn.nasa.gov/circulars/45128. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...