Document Type

Article

Publication Date

10-1-2025

Department

Department of Physics

Abstract

Supernova remnants are one potential source class considered a PeVatron (i.e., capable of accelerating cosmic rays above PeV energies). The shock fronts produced after the explosion of the supernova are ideal regions for particle acceleration. IC 443 is a supernova remnant that has been studied extensively at different wavelengths. Using 2966 days of gamma-ray data from the High Altitude Water Cherenkov (HAWC) observatory, we study the emission of IC 443 with the objective of finding signatures of cosmic-ray acceleration at the PeV scale. Using a maximum likelihood method, we find a point source located at (α=94.°42, δ=22.°35) that we associate with IC 443. The measured spectrum is a simple power law with an index of −3.14±0.18, which is consistent with previous TeV observations. Although we cannot confirm that IC 443 is a hadronic PeVatron, we do not find any sign that the spectrum has a cutoff at tens of TeV energies, with the spectrum extending to ∼30 TeV. Furthermore, we also find a new extended component in the region whose emission is described by a simple power law with an index of −2.49±0.08 and which we call HAWC J0615+2213. While we show evidence that this new source might be a new TeV halo, we defer a detailed analysis of this new source to another publication.

Publisher's Statement

© 2025. The Author(s). Published by the American Astronomical Society. Publisher’s version of record: https://doi.org/10.3847/1538-4357/adf7aa

Publication Title

Astrophysical Journal

Creative Commons License

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

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