TITLE: GCN CIRCULAR NUMBER: 44521 SUBJECT: GRB 260510C: SVOM detection of a burst DATE: 26/05/10 17:42:51 GMT FROM: Diego Gotz at CEA <diego.gotz@cea.fr> D. Gotz (CEA/Irfu), A. Saccardi (CEA/Irfu), S. Schanne (CEA/Irfu), N. Dagoneau (CEA/Irfu) report on behalf of the SVOM mission team: At 2026-05-10T17:13:44 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260510C (SVOM burst-id sb26051004), also detected by Fermi/GBM (Fermi GRB Team, GCN #44520). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 11 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 12.18 in the [8-120] keV energy band over a time window of 10.20 seconds starting at 2026-05-10T17:13:38. The localization of the best alert is R.A., Dec. 157.9595, 2.8711 degrees (J2000) with a 90% confidence level (C.L.) radius of 6.63 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a double peaked structure with a total duration of about 150 s. This burst was also detected by SVOM/GRM with a significance of 7.50. The SVOM/GRM light curve showed two separated peaks with a total duration of about 150 s. SVOM slewed to the burst. SVOM/MXT began observing the field at 2026-05-10T17:16:44 UTC, 179 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 157.941, +2.820 degrees: R.A. (J2000) = 10h31m45.8s Dec. (J2000) = 02d49m12.0s with a 90% C.L. radius of 45 arcseconds. This location is 3.26 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received. VT began observing the field after the slew. The analysis of the data will be published in a future 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 Andrea Saccardi: andrea.saccardi@cea.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/44521. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...