Evidence that Ultra-High-Energy Gamma Rays are a Universal Feature Near Powerful Pulsars

TL;DR

This study analyzes four years of HAWC data and finds that ultra-high-energy gamma-ray emission is a common feature near powerful pulsars, suggesting a universal aspect of pulsar environments.

Contribution

The paper provides the first statistical evidence that UHE gamma-ray emission is a universal feature of powerful pulsars using joint-likelihood analysis.

Findings

Significant detection of UHE gamma rays near pulsars (> 3σ)

UHE gamma-ray emission is a common feature among powerful pulsars

Pulsar environment influences gamma-ray emission levels

Abstract

The highest-energy known gamma-ray sources are all located within 0.5 degrees of extremely powerful pulsars. This raises the question of whether ultra-high-energy (UHE; $>$ 56 TeV) gamma-ray emission is a universal feature expected near pulsars with a high spin-down power. Using four years of data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, we present a joint-likelihood analysis of ten extremely powerful pulsars to search for UHE gamma-ray emission correlated with these locations. We report a significant detection ($>$ 3$\sigma$), indicating that UHE gamma-ray emission is a generic feature of powerful pulsars. We discuss the emission mechanisms of the gamma rays and the implications of this result. The individual environment that each pulsar is found in appears to play a role in the amount of emission.