GRB 260706A: Multi-instrument gamma-ray burst with X-ray and radio counterparts detected

AI Summary

GRB 260706A was detected on July 6, 2026 at 16:12:23 UTC by SVOM/ECLAIRs, SVOM/GRM, and Fermi/GBM, with a multiple-peak structure and duration of ~23 seconds. The burst had a peak energy of ~38-54 keV and fluence of ~3.5-4.0×10⁻⁶ erg/cm². Follow-up observations by Einstein Probe detected an uncatalogued X-ray source with flux 6.21×10⁻¹² erg/s/cm² (0.5-10 keV), while ATCA detected a radio counterpart at 0.2 mJy (8 GHz) ~5 days post-burst. Optical observations by SVOM/VT, LCO, REM, and GRANDMA found no optical counterpart, setting upper limits around magnitude 22.

Measurements

Notices (1)

SVOM — GRB · Mon, 06 Jul 2026 17:07:22 GMT

GCN Circulars (12)

GCN-45156 — GRB 260706A · Tue, 14 Jul 2026 14:39:13 GMT
A radio source detected by the Australia Telescope Compact Array (ATCA) is suggested to be the counterpart of the gamma-ray burst GRB 260706A, which was initially detected by SVOM/ECLAIRs and Fermi/GBM. The radio source has a flux of approximately 0.2 mJy at 8 GHz and a spectral index of 1.5, indicating self-absorption.

GCN-45128 — GRB 260706A · Thu, 09 Jul 2026 17:52:30 GMT
The GRANDMA collaboration observed the field of GRB 260706A, detected by multiple instruments, but did not find any optical counterpart. The upper limits reported are consistent with other observations, and the data was processed using a single pipeline.

GCN-45114 — GRB 260706A · Wed, 08 Jul 2026 13:58:49 GMT
The EP-FXT observatory conducted a second follow-up observation of GRB 260706A, detecting an uncatalogued source with an average unabsorbed flux of (2.5+/- 0.5) x 10^(-13) erg/s/cm^2 in the 0.5-10 keV range. This observation started approximately 27.1 hours after the initial detection by SVOM/ECLAIRs and Fermi/GBM.

GCN-45113 — GRB 260706A · Wed, 08 Jul 2026 09:45:48 GMT
The SVOM/VT telescope observed GRB 260706A, detected by multiple instruments including SVOM/Eclairs, SVOM/GRM, and Fermi/GBM, but found no credible optical sources within the error box, setting a 10-sigma upper limit of 22.0 mag in both VT_B and VT_R channels. This non-detection is consistent with observations from LCO and REM.

GCN-45103 — GRB 260706A · Tue, 07 Jul 2026 15:08:36 GMT
The SVOM/ECLAIRs team reported a refined analysis of GRB 260706A, a gamma-ray burst detected on July 6, 2026, with a multiple peak lightcurve and a duration of approximately 23.41 seconds. The burst's spectrum is best fitted by a cut-off powerlaw model, with significant fluence and photon flux measurements.

GCN-45101 — GRB 260706A · Tue, 07 Jul 2026 12:40:33 GMT
The SVOM/GRM instrument detected GRB 260706A, a gamma-ray burst with multiple peaks and a duration of 31 seconds. The burst's spectrum was analyzed, revealing a power law index of -1.47 and a cutoff energy of 53.98 keV, providing insights into the energetic processes involved.

GCN-45100 — GRB 260706A · Tue, 07 Jul 2026 12:14:45 GMT
The REM 60 cm robotic telescope at the ESO observatory of La Silla observed the field of GRB 260706A, detected by SVOM/ECLAIRs and Fermi/GBM, but did not detect any uncatalogued source within the error box in the g, r, i, z, and K bands. The observations were conducted approximately 12.6 hours after the burst and lasted for about an hour, with preliminary photometry setting upper limits on the source brightness.

GCN-45098 — GRB 260706A · Tue, 07 Jul 2026 09:30:30 GMT
The SVOM mission team observed the field of GRB 260706A using the LCO 1m telescope at Cerro Tololo Observatory but did not detect any new source within the error box, setting an upper limit on the optical brightness of r > 22.3 AB. This observation was conducted about 16 hours after the initial detection by SVOM/ECLAIRs and Fermi/GBM.

GCN-45097 — GRB 260706A · Tue, 07 Jul 2026 07:46:49 GMT
The Einstein Probe (EP) performed a follow-up observation of GRB 260706A, detected by SVOM/ECLAIRs and Fermi-GBM, identifying an uncatalogued X-ray source with an average unabsorbed flux of 6.21 x 10^(-12) erg/s/cm^2. The observation started about 1.5 hours after the initial detection and lasted for approximately 5462 seconds.

GCN-45093 — GRB 260706A · Mon, 06 Jul 2026 20:28:09 GMT
On July 6, 2026, the Fermi Gamma-ray Burst Monitor detected GRB 260706A, which was also observed by SVOM/ECLAIRs. The gamma-ray burst had a duration of about 17 seconds and was characterized by two peaks in its light curve, with a power law spectrum and a cutoff energy of approximately 47.1 keV.

GCN-45089 — GRB 260706A · Mon, 06 Jul 2026 16:50:02 GMT
The SVOM mission detected a gamma-ray burst, GRB 260706A, on July 6, 2026, at 16:12:23 UTC. The burst was also detected by Fermi/GBM and had a multiple peak structure with a T90 duration of approximately 22.9 seconds.

GCN-45088 — GRB 260706A · Mon, 06 Jul 2026 16:24:06 GMT
The Fermi Gamma-ray Burst Monitor (GBM) detected a likely long gamma-ray burst (GRB) designated GRB 260706A on July 6, 2026, at 16:12:21 UT. The event was localized to RA = 17.5, Dec = -40.6 (J2000) with a statistical uncertainty of 5.4 degrees.