GRB 260110A

General information

SVOM/ECLAIRs reports an offline detection of GRB 260110A at 2026-01-10 03:28:54.35 UTC with a ~20 s single-peaked lightcurve; the same job packet also contains multiple circulars about the fast X-ray transient EP260110a (separate sky position), so event association across these reports is uncertain.

Wavelength coverage

• Gamma/X-ray: SVOM/ECLAIRs detected GRB 260110A in 4–20 keV (and spectrum reported over 5–50 keV; fluence over 4–120 keV). Einstein Probe reports EP260110a in soft X-rays with WXT and follow-up FXT detections and spectra.
• Optical: Multiple teams report optical non-detections/upper limits for EP260110a (e.g., SVOM/VT, SVOM/C-GFT, KAIT, COLIBRÍ, BOOTES-5/JGU, TRT, MASTER, NOT).
• Near-IR: GTC/EMIR reports H-band non-detection/upper limits for EP260110a. Bands with no observations mentioned: Radio, UV, high-energy GeV (e.g., Fermi-LAT), neutrinos, gravitational waves.

Lightcurve and spectrum

• GRB 260110A (SVOM/ECLAIRs): single-peaked structure lasting ~20 s; best on-ground image trigger S/N 7.1 in 4–20 keV over 20.48 s; time-averaged 5–50 keV spectrum fit by a power law with index -1.77(-0.29/+0.33); 4–120 keV fluence (2.95 +0.32/-1.63)e-7 erg/cm^2.
• EP260110a (Einstein Probe): WXT duration ~85 s; WXT 0.5–4 keV absorbed power-law photon index 0.99(-0.47/+0.50) with unabsorbed flux 1.02(-0.30/+0.39)e-9 erg/s/cm^2; FXT 0.5–10 keV photon index 2.02(-0.14/+0.14) with unabsorbed flux 1.52(-0.19/+0.22)e-12 erg/s/cm^2; later FXT ToO photon index 2.11(-0.84/+1.00) with unabsorbed flux 1.15(-0.57/+1.33)e-13 erg/s/cm^2.

Redshift

What’s special vs typical

• The SVOM detection of GRB 260110A is reported as an offline event-by-event search, with the onboard trigger seeing the event but below the alert threshold (suggesting a marginal/sub-threshold onboard case).
• The circulars bundled under this job appear to mix two transients (GRB 260110A vs EP260110a) with inconsistent positions/timings, making interpretation atypically ambiguous.