GCN Circular 45351
Subject
GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
Event
Date
2026-08-10T20:23:02Z (21 days ago)
Edited On
2026-08-11T13:39:46Z (20 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
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 statistical 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)