GRB 260510C

General information

GRB 260510C triggered Fermi/GBM and SVOM/ECLAIRs around 2026-05-10 17:13:43–17:13:44 UT, with SVOM providing an arcminute localization and rapid follow-up identifying a fading X-ray/optical counterpart.

Wavelength coverage

• Gamma-rays: Fermi/GBM prompt emission with spectral/fluence properties; additional prompt detections by SVOM/ECLAIRs/GRM, AstroSat/CZTI, CALET/CGBM, and Glowbug.
• X-rays: SVOM/MXT discovered an uncatalogued X-ray source; MAXI/GSC reported a bright X-ray transient; Einstein Probe/FXT detected a fading X-ray source and reported a spectrum/flux.
• Optical: SVOM/VT and COLIBRÍ detected the optical counterpart and measured fading (with earlier VT limits also reported).
• Near-IR: MDM/MIRAGE detected the counterpart in J and Hs. Bands with no observations mentioned: radio, sub-mm/mm, UV, TeV.

Lightcurve and spectrum

Redshift

• z = 0.89 (photometric (host galaxy photo-z from DESI Legacy Survey association))
• Candidate counterpart position consistent with a faint galaxy in DESI Legacy Survey; reported photo-z = 0.89 ± 0.63.

What’s special vs typical