Constraints on axion-like particles from ultra-high-energy observations of M87 with the HAWC observatory

Authors

• R. Alfaro, Universidad Nacional Autónoma de México
• C. Alvarez, Universidad Autónoma de Chiapas
• A. Andrés, Universidad Nacional Autónoma de México
• E. Anita-Rangel, Universidad Nacional Autónoma de México
• M. Araya, Universidad de Costa Rica
• J. C. Arteaga-Velázquez, Universidad Michoacana de San Nicolás de Hidalgo
• N. Ghosh, Michigan Technological UniversityFollow
• M. Najafi, Michigan Technological UniversityFollow
• et al.

Document Type

Article

Publication Date

6-2026

Department

Department of Physics

Abstract

In this work, we perform an indirect search for axion-like particles (ALPs) through their hypothesized mixing with photons in the presence of magnetic fields. ALPs are a well-motivated dark-matter candidate class, and the photon-ALP conversion mechanism provides a unique channel to constrain their mass and coupling constant using very-high-energy gamma-ray observations. The photon-ALP mixing could alter the observed gamma-ray spectrum from extragalactic sources by effectively reducing the apparent attenuation due to extragalactic-background-light absorption. We analyze 7.5 years of data from the High Altitude Water Cherenkov (HAWC) Observatory, targeting the nearby radio galaxy M87. This source is located within the Virgo cluster and is an ideal environment for photon-ALP conversion due to its low redshift and the large-scale, strongly magnetized medium of the cluster. We find no evidence for a photon-ALP conversion signal and, consequently, set constraints on the ALP mass and photon-ALP coupling constant with emission from M87 which are consistent with previous results. Our analysis places competitive constraints on the ALP parameter space, defining an exclusion region in the mass range of approximately 10⁻⁸ to 10⁻⁶ eV for coupling constants above 5×10⁻¹² GeV⁻¹, complementing previous constraints from other gamma-ray observatories.

Publisher's Statement

© 2026 The Author(s). Published by Elsevier B.V. Publisher’s version of record: https://doi.org/10.1016/j.dark.2026.102260

Publication Title

Physics of the Dark Universe

Recommended Citation

Alfaro, R., Alvarez, C., Andrés, A., Anita-Rangel, E., Araya, M., Arteaga-Velázquez, J., Ghosh, N., Najafi, M., & et al. (2026). Constraints on axion-like particles from ultra-high-energy observations of M87 with the HAWC observatory. Physics of the Dark Universe, 52. http://doi.org/10.1016/j.dark.2026.102260
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2492

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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Publisher's PDF