GCN Circular 43779

H. Yang, M. Brunet, O. Godet, J.-L. Atteia (IRAP) 

report on behalf of the SVOM team:

The SVOM/ECLAIRs telescope detected GRB 260214B/EP260214b (EP team, GCN 43744
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 ), starting at 2026-02-14T22:03:41.16 UTC (T0), through an offline targeted search with the event-by-event data downloaded through 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 (SNR) of 7.06 within 4-90 keV over a time window of 6 seconds starting at T0. This event was not detected onboard because it was too faint.  

The localization of the source is RA, Dec = 191.147, 23.990 degrees:

RA (J2000) = 12h44m35s     
Dec (J2000) = 23d59m24s

with a 90% C.L. radius of 12.5 arcmin (including systematic error of 6 arcmin added in quadrature). This position is consistent with that measured by EP/WXT, with an angular separation of 10 arcmin. 

The time-averaged spectrum from T0 to T0+6 s in the energy range 4-90 keV is best fitted by a broken powerlaw, with a break energy of 8.2+/-0.9 keV, a second photon index of 1.9+0.4/-0.3, while the first photon index is not well constrained. If the first photon index is fixed to 0.7, as measured by EP/WXT, the fit yields a break energy of 10+3/-2 keV and a second photon index of 1.7+0.4/-0.3. With this model, the total energy flux in the 4-120 keV is (2.6+/-0.8)e-8 erg/cm^2/s. 

Assuming a redshift of z=1.208 (E. Le Floch et al., GCN 43749
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 ) and a standard cosmology with H_0 = 67.3 km/s/Mpc and Omega_M = 0.315 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is (2.7+/-0.8)e51 erg, and the rest-frame peak energy of the time-averaged spectrum Ep,z is 22+7/-4 keV. With these estimates, GRB 260214B/EP260214b is consistent with the distribution of Type II (long) GRBs on the Amati relation reported by Willingale et al. 2017, although it lies toward the lower end of the Ep,z and E_iso ranges. 

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@irap.omp.eu) 

Please contact him by email if you require additional information regarding the SVOM follow-up of this burst.