The Fourth HAWC Catalog of Very-High-Energy Gamma-Ray Sources
Abstract
We present an updated catalog of TeV gamma-ray sources based on the fifth pass of data from the High-Altitude Water Cherenkov (HAWC) Observatory. This release benefits from improved event reconstruction and nearly three additional years of observations. It also incorporates a systematic multi-source fitting framework, enabling more flexible and accurate modeling of the gamma-ray sky. This fitting procedure was modeled after the manual approach used in HAWC analyses of individual sources and regions, as well as other gamma-ray catalogs, like the 4FGL. In addition to more varied modeling of source morphology and spectral parameters compared to previous HAWC catalogs, this catalog uses a robust modeling of Galactic diffuse TeV emission. The fitting procedure uses both point-like and symmetric Gaussian spatial templates to model the source morphology. The spectral shape of the emission is modeled with either a simple power-law or log-parabola to explore curvature in the spectral energy distribution. We report 85 sources at the 4{\sigma} level, including 11 sources not associated with any TeVCat source using a distance-based association criterion. Distance-based association with the 1LHAASO catalog results in 22 4HWC sources without a counterpart. Additionally, there are 12 sources not associated with any physical counterpart in the Low- or High-Mass X-Ray Binary, the ATNF, or Fermi Pulsar, or SNR catalogs of sources. Five of the aforementioned sources have no counterpart in any of the catalogs searched and represent an opportunity for follow-up observations.
Cite
@article{arxiv.2602.00263,
title = {The Fourth HAWC Catalog of Very-High-Energy Gamma-Ray Sources},
author = {R. Alfaro and C. Alvarez and E. Anita-Rangel and M. Araya and J. C. Arteaga-Velazquez and D. Avila Rojas and H. A. Ayala Solares and P. Bangale and E. Belmont-Moreno and A. Bernal and K. S. Caballero-Mora and T. Capistran and A. Carraminana and F. Carreon and S. Casanova and U. Cotti and J. Cotzomi and S. Coutino de Leon and E. De la Fuente and P. Desiati and N. Di Lalla and R. Diaz Hernandez and B. L. Dingus and M. A. DuVernois and J. C. Dıaz-Velez and K. Engel and T. Ergin and C. Espinoza and K. Fang and N. Fraija and S. Fraija and J. A. Garcıa-Gonzalez and F. Garfias and N. Ghosh and M. M. Gonzalez and J. A. Gonzalez and J. A. Goodman and S. Groetsch and D. Guevel and S. Hernandez-Cadena and F. Hueyotl-Zahuantitla and P. Huntemeyer and A. Iriarte and S. Kaufmann and D. Kieda and A. Lara and K. Leavitt and T. Lewis and H. Leon Vargas and J. T. Linnemann and A. L. Longinotti and G. Luis-Raya and O. Martinez and J. Martınez-Castro and H. Martınez-Huerta and J. A. Matthews and P. Miranda-Romagnoli and E. Moreno and M. Mostafa and M. Najafi and A. Nayerhoda and L. Nellen and R. Noriega-Papaqui and N. Omodei and M. Osorio-Archila and E. Ponce and Y. Perez Araujo and E. G. Perez-Perez and Q. Remy and A. Rodriguez Parra and D. Rosa-Gonzalez and M. Roth and H. Salazar and A. Sandoval and J. Serna-Franco and Y. Son and R. W. Springer and O. Tibolla and K. Tollefson and I. Torres and R. Torres-Escobedo and R. Turner and E. Varela and L. Villasenor and I. J. Watson and H. Wu and S. Yu and X. Zhang and H. Zhou and C. de Leon},
journal= {arXiv preprint arXiv:2602.00263},
year = {2026}
}
Comments
27 pages, 21 figures, pending submission to The Astrophysical Journal