TITLE: GCN CIRCULAR NUMBER: 45180 SUBJECT: GRB 260718A : GRANDMA and KNC upper limits DATE: 26/07/18 17:08:36 GMT FROM: Alex Jacquesson <jacquessonalex179@gmail.com> GRB 260718A : GRANDMA and KNC upper limits A. Jacquesson (IJCLab), S. Antier (IJCLab), D. Turpin (CEA/Irfu), P. Hello (IJCLab), M. Freeberg (KNC), N. Kochiashvili (Ilia State University), M. Molham (NRIAG), C. Douzet (IJCLab), N. Jasmin (IJCLab), R. Le Montagner (IJCLab), K. Agabi (OCA), L. Abe (OCA), T. Guillot (OCA) on behalf of GRANDMA. We observed the field of GRB 260718A detected by SVOM/ECLAIRs (GCN 45177). The observations started with ASTEP at 2026-07-18T14-47-18 UTC on the 18th of July 2026 about 4h post ECLAIRs T0. We didn't detect any optical counterpart within a region centered on ECLAIRs localization error box and with a radius above 8 arcmin with the GRANDMA network with ASTEP at Concordia and KNC-T30. We reported our upper limit in the public ACME service Skyportal/ICARE https://skyportal-icare.ijclab.in2p3.fr/source/GCN-260718_111632. To access, one simply needs to create an account using your ORCID id. Our upper limit are coherent with SVOM/VT (GCN 45178 and 45179) 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). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). 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/45180. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...