TITLE: GCN CIRCULAR NUMBER: 45351 SUBJECT: GRB 250607A: SVOM/ECLAIRs detection through offline targeted search DATE: 26/08/10 20:23:02 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> H. Yang, O. Godet, S. Guillot (IRAP), D. Turpin (CEA) report on behalf of the SVOM team: The SVOM/ECLAIRs telescope detected GRB 250607A, also detected by Fermi/GBM (GCN 40648) and SVOM/GRM (GCN 40651), starting at 2025-06-07T14:00:51 UTC (T0), through an offline targeted search with the event-by-event data downloaded via the X-band ground station. The burst was detected within several timescales and energy ranges. The best detection is obtained by the image trigger with a signal-to-noise ratio of 7.4 within 4-20 keV over a time window of 10 s starting at T0. This event was not detected onboard because it was too faint and near the edge of the field of view. The ECLAIRs lightcurve shows a multi-peaked structure lasting around 10 s, with most of the detected photons below 50 keV. The localization of the source is RA, Dec = 228.408, -19.894 degrees: RA (J2000) = 15h13m38s Dec (J2000) = -19d53m38s with a 90% C.L. radius of 10.8 arcmin (including systematic error of 2 arcmin added in quadrature). This localization is broadly consistent with that reported by Fermi/GBM (GCN 40648). The angular separation between the two positions is 15 degrees, which is compatible with the 10.15 degrees systematic uncertainty of the GBM localization. The time-averaged spectrum from T0 to T0+10 s in the 5-120 keV is well fitted by a power law with a photon index of 1.6+/-0.2 and a corresponding 4-120 keV fluence of (1.2+/-0.3)e-6 erg/cm^2. The spectral properties measured with SVOM/ECLAIRs are consistent with those reported by SVOM/GRM (GCN 40651). All quoted errors are at the 68% confidence level. 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/ECLAIRs point of contact for this event is : Hui Yang (hui.yang@cnrs.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45351. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...