HAWC Study on the Ultra-high-energy Gamma-Ray Emissions from the Pulsar Wind Nebula G32.64+0.53

Authors

• R. Alfaro, Universidad Nacional Autónoma de México
• C. Alvarez, Universidad Autónoma de Chiapas
• 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
• D. Avila Rojas, Universidad Nacional Autónoma de México
• N. Ghosh, Michigan Technological University
• D. Guevel, Michigan Technological University
• P. Huntemeyer, Michigan Technological UniversityFollow
• K. Leavitt, Michigan Technological UniversityFollow
• M. Najafi, Michigan Technological UniversityFollow
• et al.

Document Type

Article

Publication Date

9-14-2026

Department

Department of Physics

Abstract

Multi-TeV gamma-ray emission around eHWC J1850+001 (a source from the first HAWC catalog of gamma-ray sources emitting above 56 TeV) is spatially coincident with the pulsar wind nebula (PWN) G32.64+0.53, powered by PSR J1849-0001. The absence of counterparts in radio, optical, and GeV energy ranges, contrasted with clear detections in X-rays and very-high-energy (VHE) gamma rays, is indicative of a nonthermal leptonic origin for the nebula. We apply a systematic analysis pipeline, including a sophisticated model for the Galactic diffuse emission, to 2860 days of data from the HAWC Observatory. Our detailed analysis confirms that the ultra-high-energy (UHE) emission originates from G32.64+0.53, and we measure its spectrum up to 270 TeV with significant emission well beyond 100 TeV. We fit the multiwavelength observations with a time-dependent leptonic model powered by the pulsar’s rotational energy, and the results establish the nebula as a leptonic PeV accelerator, capable of accelerating electrons to a maximum energy of Ecut ≥ 2.9 PeV (95% one-sided lower bound). The model also constrains the nebular magnetic field to 4.28 μG, supporting a leptonic PWN origin for the observed UHE emission.

Publisher's Statement

© 2026. The Author(s). Published by the American Astronomical Society. Publisher’s version of record: https://doi.org/10.3847/1538-4357/ae975c

Publication Title

Astrophysical Journal

Recommended Citation

Alfaro, R., Alvarez, C., Anita-Rangel, E., Araya, M., Arteaga-Velázquez, J., Rojas, D., Ghosh, N., Guevel, D., Huntemeyer, P., Leavitt, K., Najafi, M., & et al. (2026). HAWC Study on the Ultra-high-energy Gamma-Ray Emissions from the Pulsar Wind Nebula G32.64+0.53. Astrophysical Journal, 1009(1). http://doi.org/10.3847/1538-4357/ae975c
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2972

Creative Commons License

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

Version

Publisher's PDF