IceCube-260315A

General information

IceCube-260315A is a track-like high-energy neutrino candidate detected by IceCube (Astrotrack BRONZE stream) on 2026-03-15 02:19:06.60 UTC, followed by optical, X-ray, and gamma-ray searches including reports on an optical/X-ray candidate AT2026fpm.

Wavelength coverage

• Neutrinos: IceCube detection; follow-up searches for additional events reported none in ±500 s and ±2 days.
• Optical: MASTER reported AT2026fpm (CLEAR ~19.2) near the errorbox; COLIBRÍ detected it in g/r/z; ZTF covered most of the localization with no candidates reported.
• X-ray: Einstein Probe/FXT detected an X-ray source consistent with AT2026fpm.
• Gamma-ray (GeV): Fermi-LAT reports no significant new excess and provides flux upper limits.
• Radio/UV/IR/TeV: No observations mentioned.

Lightcurve and spectrum

Redshift

A redshift z=1.389 is reported for a QSO stated to be spatially consistent with the X-ray/optical source position.

What’s special vs typical

The main candidate counterpart (AT2026fpm) is reported to coincide with a flagged variable catalog source and is stated to be spatially consistent with a QSO at z=1.389, with no supporting additional neutrino events or LAT gamma-ray excess.