Possible faint GRB 260818A detected by SVOM with no optical counterpart found.

AI Summary

The SVOM mission detected a faint gamma-ray burst (GRB) with a signal-to-noise ratio of 6.86 in the 8-120 keV band. Follow-up observations by multiple telescopes did not identify any optical counterparts within the ECLAIRs localization region.

Measurements

Notices (1)

SVOM — GRB · Tue, 18 Aug 2026 01:03:14 GMT

GCN Circulars (5)

GCN-45406 — GRB 260818A · Thu, 20 Aug 2026 03:58:10 GMT
The field of GRB 260818A was observed in the J-band using the Palomar 1-m telescope equipped with the WINTER camera, starting 6.61 hours after the SVOM/ECLAIRs trigger. No counterparts were detected for two of the five unique uncatalogued X-ray sources reported, with a 5-sigma upper limit of J=19.14 mag (AB) obtained.

GCN-45404 — GRB 260818A · Wed, 19 Aug 2026 20:26:12 GMT
The SVOM/ECLAIRs team reported a refined analysis of the possible faint burst GRB 260818A, detected from 82 seconds before the trigger time to the trigger time itself in the 8-120 keV energy band. The burst showed a featureless light curve and was well fitted by a blackbody model with a temperature of approximately 7 keV.

GCN-45395 — GRB 260818A · Tue, 18 Aug 2026 15:08:30 GMT
The SVOM mission team observed the field of GRB 260818A using the LCO 1m telescope and did not detect any credible uncatalogued source in the ECLAIRs localization region. The upper limits for the optical detection were measured as r > 21.8 AB and z > 20.5 AB, indicating the absence of a detectable optical transient.

GCN-45393 — GRB 260818A · Tue, 18 Aug 2026 09:54:29 GMT
The SVOM/COLIBRÍ telescope observed the field of GRB 260818A but did not detect any new optical source at the ECLAIRs source position, setting an upper limit of r > 22.3 and z > 20.4 magnitudes. Further observations are ongoing.

GCN-45391 — GRB 260818A · Tue, 18 Aug 2026 01:59:59 GMT
The SVOM mission detected a possible long and faint gamma-ray burst (GRB 260818A) on August 18, 2026, at 01:04:36 UTC. The burst was detected by the Image Trigger (IMT) with a signal-to-noise ratio of 6.86 in the 8-120 keV energy band over 81.92 seconds, and its localization includes several quasars.