Recent Results from the High Altitude Water Cherenkov Observatory

Kelly Malone

doi:10.1051/epjconf/202023507001

Abstract

The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, anextensive air shower detector consisting of 300 water Cherenkov tanks located at 4100m in Puebla, Mexico, has been surveying the TeV gamma-ray sky for almost five years. HAWC can observe steady sources, variable sources, transients, which allows for probes of both astrophysical and particle physics phenomena. This includes the production and propagation of cosmic rays, studies of Lorentz invariance violation, and dark matter searches. I will discuss recent HAWC results as well as the future of the observatory.

Highlights

Cosmic-ray origins and propagationIt is a known fact that cosmic rays (CRs) are accelerated to ∼1020 eV in nature [1], but which sources are responsible for this and the exact mechanisms are still largely open questions
CR acceleration is inherently interesting since the energies involved are much higher than can be reached by accelerators on Earth, but since cosmic rays are charged they bend in magnetic fields on their way to the Earth and it is somewhat difficult to pinpoint their origins
CRs interact with their environment; neutral pions are created in this process

Summary

Introduction

It is a known fact that cosmic rays (CRs) are accelerated to ∼1020 eV in nature [1], but which sources are responsible for this and the exact mechanisms are still largely open questions. CRs interact with their environment (such as the interstellar medium); neutral pions are created in this process. These neutral pions decay to gamma rays. Since gamma rays are not charged, they point back to sites of CR acceleration. This is the hadronic production mechanism of gamma rays. Distinguishing between hadronic and leptonic gamma-ray sources (and identifiying which sources may be associated with cosmic rays) is a challenge in the field. The Klein Nishina component causes the gamma-ray emission to become suppressed starting at a few tens of TeV, resulting in an energy-dependent spectral index and curvature in the spectra [2]

Introduction to HAWC