GRB 241030B: SVOM/ECLAIRs detection of a burst

During the commissioning phase, the SVOM/ECLAIRs telescope triggered and localized GRB 241030B at 2024-10-30T18:34:19 UTC (Tb) which was also detected by Fermi GBM (Fermi GBM team, GCN 37980), Swift BAT (Klingler et al, GCN 37981) and Swift XRT (Evans et al, GCN 37983). 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 15 alerts were received. The light-curve shows a single peak of about 8 s duration. The CRT detected the burst on time-windows from 2.56 to 20.48 s duration. The best detection is obtained by CRT with a signal-to-noise ratio of 37.6 in the 8-120 keV energy band over a time window of 5.12 s starting at Tb. The GRB localization is RA, Dec = 50.794, 34.439 (J2000). The statistical uncertainty on this position is 2.3 arcminutes, to which we recommend adding 2 arcminutes of systematic uncertainty in quadrature. An automatic slew on this position was performed by SVOM upon request by the onboard trigger. 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: stephane.schanne AT cea.fr