First HAWC Spectra of Galactic Gamma-ray Sources Above 100 TeV and the Implications for Cosmic-ray Acceleration

TL;DR

This paper reports the first catalog of the highest-energy gamma-ray sources detected by HAWC above 56 TeV and 100 TeV, providing insights into potential Galactic cosmic-ray accelerators called PeVatrons.

Contribution

It introduces new all-sky gamma-ray source catalogs at energies above 56 TeV and 100 TeV, utilizing advanced energy reconstruction algorithms for unprecedented energy resolution.

Findings

Detected the highest-energy gamma-ray sources ever observed.

All sources are associated with known Galactic gamma-ray emitters.

Some sources may be PeVatron candidates capable of accelerating cosmic rays to PeV energies.

Abstract

We present the first catalogs of the highest-energy (above 56 TeV and 100 TeV) gamma-ray sources seen by the High Altitude Water Cherenkov (HAWC) Observatory. The wide field-of-view of HAWC naturally lends itself to unbiased all-sky surveys and newly developed event-by-event gamma-ray energy reconstruction algorithms have allowed unprecedented energy resolution. The sources presented here are the highest-energy sources ever detected. All are coincident with known lower-energy gamma-ray sources within our Galaxy. These objects may have implications for the sources of Galactic cosmic rays; since Galactic CRs have been observed up to PeV energies, sources accelerating particles to these energies must exist. These sources, called "PeVatrons", would have corresponding hard gamma-ray spectra that extend to high energies without any spectral break or cutoff. We will present measurements of the spectra of these highest-energy gamma-ray sources and discuss if any of them can be identified as PeVatron candidates.