Study of the IC 443 region with the HAWC observatory

TL;DR

This study analyzes gamma-ray data from the HAWC observatory to investigate IC 443, a supernova remnant, for signs of cosmic-ray acceleration up to PeV energies, revealing a point source and a potential new TeV halo.

Contribution

First detailed HAWC analysis of IC 443 showing a point source and a new extended component, suggesting possible PeV cosmic-ray acceleration and a new TeV halo.

Findings

Detected a point source associated with IC 443 with a power-law spectrum extending to ~30 TeV.

Identified a new extended gamma-ray emission component, possibly a TeV halo.

Spectrum shows no cutoff at tens of TeV, consistent with PeVatron activity.

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 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 ($\alpha$=94.42$^{\circ}$, $\delta$=22.35$^{\circ}$) that we associate with IC 443. The measured spectrum is a simple power law with an index of $-3.14\pm$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 cut off at tens of TeV energies, with the spectrum extending to $\sim$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\pm$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.