TITLE: GCN CIRCULAR NUMBER: 45452 SUBJECT: GRB 260818B: 6 GHz VLA observations DATE: 26/08/27 08:00:19 GMT FROM: Roberto Ricci at INAF-IRA <ricci@ira.inaf.it> R. Ricci, M. Yadav, E. Troja (U Rome) report: We observed the field of short duration GRB 260818B, detected by SVOM (Cordier et al., GCN 45398) with the Karl G. Jansky Very Large Array in C-band at the centre frequency of 6 GHz with a bandwidth of 4 GHz on August 25th 2026 at mid-time 13:37 UT(6.7 days after the trigger). Data were calibrated and imaged using standard procedures in CASA (v6.6.1). 3C48 was used for flux density and bandpass calibration and J0321+1221 was used for complex gain calibration. The full C-band field-of-view centred at the SVOM/ECLAIRs position (Cordier et al., GCN 45398) was imaged in CASA using the task tclean. We detect all the radio sources previously reported by Schroeder et al. (GCN 45418). S3 is detected at a flux of ~75 uJy and we cannot confirm it as a possible radio counterpart. Among the remaining sources, S5, S9 and S10 show a consistent fading trend across all epochs. S5 and S10 are coincident with catalogued sources and, given the relatively large beam size (11x9 arcsec), we cannot distinguish whether their variability is intrinsic or caused by the GRB afterglow. However, we note that S10 lies close to the candidate optical afterglow (Ducoin et al., GCN 45450). Further observations are planned. We thank the VLA staff for executing the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/45452. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...