Investigating IceCube Neutrino Alerts with the HAWC $\gamma$-Ray Observatory
Abstract
Neutrino emission from astrophysical sources has long been considered a signature of cosmic-ray acceleration. The IceCube neutrino observatory has observed a diffuse flux of TeV-PeV neutrinos, but very few confirmed sources have emerged. With the recent publication of IceCube Event Catalog (IceCat-1), IceCube has released a list of the most promising astrophysical neutrino events since May 2011. Using the archival data from the High Altitude Water Cherenkov (HAWC) -ray observatory, we perform a coincidence search for gamma rays and neutrinos using a Bayesian Block algorithm with the public IceCube alerts from IceCat-1, along with additional alerts issued later. In this work, we consider 368 alerts, up to July 8, 2025, that are within HAWC's field of view. We observe approximately a 5\% coincident detection rate, which is consistent with expectations from background. Two of these detections contain the Active Galactic Nuclei (AGN) Markarian 421 and Markarian 501. We discuss the likelihood that the neutrino/-ray coincidences are false positives and a brief overview of the results.
Cite
@article{arxiv.2602.16818,
title = {Investigating IceCube Neutrino Alerts with the HAWC $\gamma$-Ray Observatory},
author = {The HAWC Collaboration and R. Alfaro and C. Alvarez and A. Andrés and E. Anita-Rangel and M. Araya and J. C. Arteaga-Velázquez and D. Avila Rojas and H. A. Ayala Solares and R. Babu and E. Belmont-Moreno and A. Bernal and K. S. Caballero-Mora and T. Capistrán and F. Carreón and S. Casanova and J. Cotzomi and S. Coutiño de León and C. de León and E. De la Fuente and P. Desiati and N. Di Lalla and R. Diaz Hernandez and M. A. DuVernois and J. C. Díaz-Vélez and K. Engel and C. Espinoza and N. Fraija and S. Fraija and A. Galván-Gámez and J. A. García-González and F. Garfias and N. Ghosh and A. Gonzalez Muñoz and M. M. González and J. A. González and J. A. Goodman and D. Guevel and J. Gyeong and J. P. Harding and S. Hernández-Cadena and I. Herzog and J. Hinton and D. Huang and F. Hueyotl-Zahuantitla and P. Hüntemeyer and A. Iriarte and S. Kaufmann and D. Kieda and K. Leavitt and J. Lee and W. H. Lee and H. León Vargas and J. T. Linnemann and A. L. Longinotti and G. Luis-Raya and K. Malone and O. Martinez and J. Martínez-Castro and J. A. Matthews and P. Miranda-Romagnoli and P. E. Mirón-Enriquez and E. Moreno and M. Mostafá and M. Najafi and A. Nayerhoda and L. Nellen and M. U. Nisa and R. Noriega-Papaqui and N. Omodei and M. Osorio-Archila and E. Ponce and Y. Pérez Araujo and E. G. Pérez-Pérez and C. D. Rho and D. Rosa-González and M. Roth and H. Salazar and D. Salazar-Gallegos and A. Sandoval and M. Schneider and J. Serna-Franco and M. Shin and A. J. Smith and Y. Son and R. W. Springer and O. Tibolla and K. Tollefson and I. Torres and R. Torres-Escobedo and E. Varela and L. Villaseñor and X. Wang and Z. Wang and I. J. Watson and H. Wu and S. Yu and H. Zhou},
journal= {arXiv preprint arXiv:2602.16818},
year = {2026}
}