GCN Circular 45166
Subject
EP260703a: SVOM/ECLAIRs Upper Limit
Event
Date
2026-07-15T10:13:13Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
H. Yang, O. Godet (IRAP), S. Schanne (CEA)
report on behalf of the SVOM team:
We performed a targeted search to the X-ray transient EP260703a, detected by EP-WXT at 2026-07-03T03:13:57 UTC (T0) lasting for about 50 s (EP team, GCN 45070), with the SVOM/ECLAIRs event-by-event data downloaded through the X-band ground station.
At T0, the transient position was within the ECLAIRs field of view (FoV), although ~90% of the FoV was occulted by the Earth. No statistically significant signal was identified within the T0 +/- 1000 s interval by the ECLAIRs image trigger performed on multiple timescales and energy bands. For the interval from T0 to T0 + 50 s, we derive a 3-sigma upper limit of 2e-8 erg/cm^2/s in the 4-120 keV band assuming a power-law model with a photon index of 0.22 measured by EP-WXT (GCN 45070), or 6e-9 erg/cm^2/s assuming a soft power-law model with a photon index of 2.0.
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)