TITLE: GCN CIRCULAR NUMBER: 44823 SUBJECT: GRB 260604C: SVOM detection of a long burst DATE: 26/06/04 20:43:09 GMT FROM: Diego Gotz at CEA <diego.gotz@cea.fr> D. Gotz, D. Adrien, N. Dagoneau, S. Bisero (CEA Saclay) report on behalf of the SVOM mission team: At 2026-06-04T20:21:59 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260604C (SVOM burst-id sb26060404). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was only detected by the Image Trigger (IMT), which produced a sequence of 4 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.23 in the [5-20] keV energy band over a time window of 163.84 seconds starting at 2026-06-04T20:19:56 UTC. The localization of the best alert is R.A., Dec. 224.3461, 28.6558 degrees: R.A. (J2000) = 14h57m23s Dec. (J2000) = 28d39m20s with a 90% confidence level (C.L.) radius of 9.6 arcmin (including systematic error of 2 arcmin added in quadrature). This position is compatible with the GRB detected by Fermi/GBM GCN 44822 . SVOM slewed to the burst position. No X-ray observation could be performed by SVOM/MXT for the time being. Optical observations by VT will be published in a further circular. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Sofia Bisero: sofia.bisero@cea.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/44823. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...