Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Figure 1

$\sqrt{\mathrm{TS}}$ map of the galactic plane for $\widehat{E}>56\mathrm{TeV}$ emission. A disk of radius 0.5° is assumed as the morphology. Black triangles denote the high-energy sources. For comparison, black open circles show sources from the 2HWC catalog.

Figure 2

The same as Fig. 1, but for $\widehat{E}>100\mathrm{TeV}$. The symbol convention is identical to Fig. 1.

Figure 3

The spectra of the three sources exhibiting significant $\widehat{E}>100\mathrm{TeV}$ emission. For each source, the line is the overall forward-folded best fit. The error bars on the flux points are statistical uncertainties only. The shaded band around the overall best fit line shows the systematic uncertainties related to the HAWC detector model, as discussed in [19]. The Crab Nebula spectrum from [19] is shown for comparison.