General information
IceCube-260704A is a track-like IceCube Astrotrack Bronze high-energy neutrino candidate detected on 2026-07-04 at 07:16:58.19 UT at RA 320.67 deg, Dec +34.14 deg, with FAR 0.8177 yr^-1. Multiple follow-up circulars report no convincing temporally associated electromagnetic or additional-neutrino counterpart.
Wavelength coverage
- Neutrino: IceCube reported the Bronze alert and later found zero additional track-like events in both 1000 s and 2 day searches, with p-value 1.00 in each window.
- Optical: OHP/T193 MISTRAL observed WISEA J212302.62+340634.2 in r band and spectroscopy; ZTF observed 98.4% of the localization in g and r about 0.1 hr after the neutrino.
- Gamma-ray: Fermi-LAT found no cataloged source in the 90% localization and no significant >5 sigma new >100 MeV excess.
- Infrared: WISE colors were used to classify ZTF19ablafcb as likely AGN-like, but no new infrared follow-up is reported.
No observations are mentioned in radio, X-ray, or gravitational-wave bands.
Lightcurve and spectrum
- OHP/T193 r-band imaging of WISEA J212302.62+340634.2 at 18.8 hr after trigger found no significant magnitude change compared with Pan-STARRS r=18.05.
- OHP/T193 spectroscopy detected Halpha at z=0.1402, intense double-peaked [NII] 6584 A emission, and Mg 5175 A, CaFe 5269 A, and NaD 5892 A absorption.
- The reported log(Halpha/[NII]) is close to -0.1, likely placing the galaxy in the AGN/LINER region of a BPT diagram.
- A second OHP/T193 spectrum around 40 hr after trigger again detected Halpha at the same redshift and similar intensity; [NII] may show mild evolution.
- ZTF selected ZTF19ablafcb at g=21.09 +/- 0.20, but it was previously detected in 2019, appears AGN-like, and was not significantly flaring relative to archival baseline.
- Fermi-LAT reports 95% >100 MeV flux upper limits of <3.4e-10 ph cm^-2 s^-1 over ~18 years, <1.9e-08 over 1 month, and <1.2e-07 over 1 day before T0.
Redshift
OHP/T193 MISTRAL spectroscopy reports z=0.1402 for WISEA J212302.62+340634.2 from Halpha and [NII] emission lines. This source is about 4.9 arcmin from the IceCube mean coordinates, but the circulars do not establish it as the neutrino counterpart.
What’s special vs typical
The most notable feature is the presence of an AGN/LINER-like galaxy near the neutrino direction with double-peaked [NII] emission and a measured redshift. Against that, the event currently looks typical for a followed-up IceCube Bronze alert because the reported follow-up is dominated by nondetections or non-flaring sources rather than a confirmed counterpart.