EAS Arrays at High Altitudes Start the Era of UHE γ-ray Astronomy

Zhen Cao

doi:10.3390/universe7090339

Abstract

The evolution of extensive air shower detection as a technique for γ-ray astronomical instrumentation for the last three decades is reviewed. The first discoveries of galactic PeVatrons by the Large High Altitude Air Shower Observatory demonstrate the importance of this technique in ultra-high energy γ-ray astronomy. Utilizing this technique, the origins of high energy cosmic rays may be discovered in the near future.

Highlights

As of today, the Large High Altitude Air Shower Observatory (LHAASO) has detected a dozen PeVatrons
As this technology may soon lead to further important discoveries, this paper reviews the history of extensive air shower (EAS) detection technology in γ-ray astronomy, outlining major achievements, advantages and disadvantages
Three generations of the detectors using various techniques are clearly shown in the figure according to the improvement of their sensitivity from 1 Crab Unit (CU) for the 1st generation to 0.01 CU for the 3rd generation represented by LHAASO

Summary

Introduction

The Large High Altitude Air Shower Observatory (LHAASO) has detected a dozen PeVatrons. It is a discovery that opens the window to Ultra High Energy (UHE, Eγ > 0.1 PeV) γ-ray observation. The traditional cosmic ray (CR) detection method of observing extensive air shower (EAS) on the ground has evolved as a successful γ-ray detecting technique over three decades of remarkable development. The long-standing mystery of galactic CR origins may be uncovered in this new era of UHE CR observation utilizing EAS detection at high altitudes. As this technology may soon lead to further important discoveries, this paper reviews the history of EAS detection technology in γ-ray astronomy, outlining major achievements, advantages and disadvantages

The Pioneers of EAS Arrays for γ-ray Astronomy

Altitudes of the EAS Array

Background

LHAASO

Findings

Summary