TITLE: GCN CIRCULAR NUMBER: 37749 SUBJECT: GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs DATE: 24/10/09 20:11:51 GMT FROM: Stéphane Schanne at CEA Paris-Saclay/IRFU SVOM/ECLAIRs Commissioning Team: Jean-Luc Atteia, Laurent Bouchet, Sebastien Guillot, Juliette Alaux (IRAP), Stéphane Schanne, Frédéric Chateau, Nicolas Dagoneau, Hervé Le Provost (CEA), Wenjin Xie (NAOC),Floriane Cangemi (APC), Tais Maiolino (LUPM), Karine Mercier, Marie-Claire Charmeau, Stefano Crepaldi (CNES) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV) Report on behalf of the SVOM team: During the commissioning phase, the SVOM/ECLAIRs telescope triggered and located GRB 241009A (sb24100915) at 2024-10-09T19:17:29 UT (Tb). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Image Trigger (IMT) and 12 Alerts were received. The detection with the best signal-to-noise ratio of 15.3 sigma is obtained by CRT in the 8-50 keV energy band over a time window of 10.24 s starting at Tb. This is a clear long duration GRB. The median location of the event on all 12 Alerts is RA, Dec = 325.11, -35.63 (J2000). The statistical uncertainty on this position is 5.6 arcminutes, to which we recommend adding 10 arcminutes of systematic uncertainty in quadrature. The SVOM satellite did not slew onto this burst. The Space 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. ECLAIRs was developed jointly by APC, CEA, CNES, and IRAP. The SVOM point of contact for this burst is: olivier.godet AT irap.omp.eu