GRB 260726A detected by Fermi GBM and SVOM, with optical counterpart

AI Summary

A gamma-ray burst (GRB 260726A) was detected by Fermi GBM and SVOM/ECLAIRs, with a refined position and a well-fitted spectrum. Follow-up observations revealed an optical counterpart and upper limits on X-ray emissions.

Measurements

Notices (1)

Fermi GBM — GRB · Sun, 26 Jul 2026 23:44:49 GMT

GCN Circulars (10)

GCN-45259 — GRB 260726A · Thu, 30 Jul 2026 23:53:05 GMT
The SVOM/ECLAIRs team reported a refined analysis of GRB 260726A, a gamma-ray burst detected on July 26, 2026, with a single peak lightcurve and a duration of 63 seconds. The burst's spectrum is best fitted by a powerlaw with an exponential cutoff model, and it was also detected by Fermi/GBM.

GCN-45249 — GRB 260726A · Wed, 29 Jul 2026 03:29:48 GMT
The SVOM mission team conducted follow-up observations of GRB 260726A, initially detected by SVOM/ECLAIRs and Fermi/GBM, using the EP-FXT instrument. No X-ray counterpart was detected, with an estimated flux upper limit of 1.16 x 10^(-13) erg cm^-2 s^-1 in the 0.5–10 keV energy band, and multiple optical follow-up observations were also performed.

GCN-45246 — GRB 260726A · Tue, 28 Jul 2026 22:06:21 GMT
On July 26, 2026, the Fermi Gamma-ray Burst Monitor detected GRB 260726A, a gamma-ray burst with a duration of 19 seconds and a peak photon flux of 1.4 ph/s/cm^2. The event was also observed by the SVOM satellite and the Liverpool Telescope, confirming its optical counterpart.

GCN-45241 — GRB 260726A · Tue, 28 Jul 2026 11:04:58 GMT
The Liverpool Telescope detected an optical source in the i-band at the position of the candidate counterpart of GRB 260726A, approximately 26 hours after the Fermi trigger, with a magnitude of 22.58 ± 0.16. No source was detected in the r-band, with an upper limit of 22.03.

GCN-45232 — GRB 260726A · Mon, 27 Jul 2026 19:19:29 GMT
The field of GRB 260726A was observed in the J-band using the Palomar 1-m telescope with the WINTER camera, but no new source was detected at the position of the SVOM/VT optical candidate, resulting in a 5-sigma upper limit of J = 18.92 mag (AB). This non-detection provides constraints on the near-infrared brightness of the transient associated with GRB 260726A.

GCN-45230 — GRB 260726A · Mon, 27 Jul 2026 17:26:25 GMT
The SVOM/VT telescope detected an uncatalogued optical candidate associated with the gamma-ray burst GRB 260618B, which was also observed by SVOM/ECLAIRs, SVOM/GRM, and Fermi/GBM. The optical source, located at R.A. 23:47:31.93, Dec. +52:52:12.69, showed a fading slope of about -0.2 in the VT_R band.

GCN-45229 — GRB 260726A · Mon, 27 Jul 2026 17:05:01 GMT
The SVOM mission has improved the position of GRB 260726A to RA=356.770, Dec=52.851 with a 90% confidence level of 3.7 arcmin. The SVOM MXT instrument has tentatively detected a faint fading source near the improved position, which is 4.95 arcmin from the ECLAIRs position.

GCN-45221 — GRB 260726A · Mon, 27 Jul 2026 01:46:31 GMT
The MASTER-SAAO robotic telescope in South Africa began observing the error box of Fermi GRB 260726A approximately 3746 seconds after the notice time, with an upper limit magnitude of 17.5. The observations were conducted under challenging conditions, including a high zenith distance and low sun altitude, and no optical transient was detected.

GCN-45219 — GRB 260726A · Mon, 27 Jul 2026 00:23:38 GMT
The SVOM mission detected a gamma-ray burst, GRB 260726A, on July 26, 2026, at 23:45:23 UTC. The burst was also detected by Fermi/GBM and localized with a 90% confidence radius of 5.68 arcmin.

GCN-45218 — GRB 260726A · Sun, 26 Jul 2026 23:55:25 GMT
The Fermi Gamma-ray Burst Monitor (GBM) detected a likely long gamma-ray burst (GRB 260726A) on July 26, 2026, at 23:44:49 UT. The event was located at RA = 19.0, Dec = 52.4 (J2000) with a statistical uncertainty of 11.9 degrees.