TITLE: GCN CIRCULAR NUMBER: 40695 SUBJECT: GRB 250610B - SVOM/ECLAIRs refined analysis DATE: 25/06/12 07:39:53 GMT FROM: ogodet@irap.omp.eu
Authors: O. Godet (IRAP), A. Coleiro (APC), M.-G. Bernardini (INAF-OAB, LUPM), A. Saccardi (CEA), J. Rodriguez (CEA)
Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 250610B (SVOM burst-id sb25061018).
The burst that triggered ECLAIRs onboard (GCN #40671) consists of a single large peak with a duration of T90 = 108.25 -13.14 / +34.95 s in the 4-120 keV energy band.
The time-averaged spectrum from T0-10s to T0+80s (T0 = 2025-06-10T16:32:58 UTC) in the energy range 5-120 keV is best fitted by a cutoff powerlaw model with a photon index of 0.9 +/- 0.1 and a cutoff energy of 49 +14/-10 keV. This translates to a Epeak-value of 53 +16/-12 keV. These spectral parameters are consistent with those obtained by SVOM/GRM (GCN #40683). With this model, the total 4-120 keV fluence is (2.9 +0.1/-0.4)e-6 erg/cm^2.
All the quoted errors are given at the 68% confidence level.
Given that the ECLAIRs calibration is still on-going, the above results shall be seen as preliminary.
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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC.
The SVOM/ECLAIRs point of contact for this burst is: O. Godet (IRAP) (ogodet at irap.omp.eu)
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