Ultra-High-Energy Gamma-Ray Astronomy

Abstract

Ultra-High Energy (UHE, $>$0.1\,PeV) $\gamma$-ray Astronomy is rapidly evolving into an expanding branch of the $\gamma$-ray astronomy with the surprising discovery of 12 PeVatrons and the detection of a handful of photons above 1 PeV. Nearly all known celestial object types that have emissions in the TeV band are found also emitting UHE photons. UHE $\gamma$-rays have a well-defined horizon inside our galaxy due to the absorption of infrared and cosmic microwave backgrounds in the universe. With the last 30 years, traditional cosmic ray (CR) detection techniques allow the detection of UHE $\gamma$-rays, and opened up the last observation window. For leptonic sources, UHE radiation is in the deep Klein-Nishina regime which is largely suppressed. Therefore UHE $\gamma$-ray detection will help to locate and identify hadronic radiation sources, tracing the historic pursuit for the origin of CRs around the knee of the spectrum. The Crab Nebula is again the focus of attention with measured photon emissions above 1\,PeV. In the absence of hadronic processes, this may indicate the existence of an extreme accelerator of e${}^{+}$/e${}^{-}$. Utilization of the CR extensive air shower detection techniques broadens the field of view of the source observations, enabling the measurement of UHE radiation surrounding the sources. These observations can probe the particle propagation inside and outside the accelerators and the subsequent injection/escape into the interstellar medium.

23 pages, 6 figures, to appear in Annual Review of Nuclear and Particle Science

References in corpus (31)

• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth
• Primary particle acceleration above 100 TeV in the shell-type Supernova Remnant RX J1713.7-3946 with deep H.E.S.S. observations
• Teraelectronvolt Astronomy
• TeV Gamma-Ray Sources from a Survey of the Galactic Plane with Milagro
• Analytical solutions for energy spectra of electrons accelerated by nonrelativistic shock-waves in shell type supernova remnants
• First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies
• First detection of VHE gamma-rays from SN 1006 by H.E.S.S
• A radiation transfer model for the Milky-Way: I. Radiation fields and application to High Energy Astrophysics
• Identification of the TeV Gamma-ray Source ARGO J2031+4157 with the Cygnus Cocoon
• Potential PeVatron supernova remnant G106.3+2.7 seen in the highest-energy gamma rays
• AGILE detection of GeV gamma-ray emission from the SNR W28
• Observation of the Cosmic Ray Moon shadowing effect with ARGO-YBJ
• The Hunt for Pevatrons: The Case of Supernova Remnants
• Gamma-ray halos around pulsars as the key to understanding cosmic ray transport in the Galaxy
• Fermi Large Area Telescope Performance After 10 Years Of Operation
• HAWC J2227+610 and its association with G106.3+2.7, a new potential Galactic PeVatron
• On the potential of bright, young pulsars to power ultra-high gamma-ray sources
• Discovery of the hard spectrum VHE gamma-ray source HESS J1641-463
• Constraining the magnetic field in the TeV halo of Geminga with X-ray Observation
• Diffuse gamma-ray emission toward the massive star-forming region, W40
• The Physics of Pulsar Halos: Research Progress and Prospect
• Evidence for PeV Proton Acceleration from Fermi-LAT Observations of SNR G106.3+2.7
• The diffuse gamma-ray emission toward the Galactic mini starburst W43
• Gamma-ray Observation of the Cygnus Region in the 100 TeV Energy Region
• Multi-band Emission up to PeV Energy from the Crab Nebula in a Spatially Dependent Lepto-hadronic Model
• Ultrahigh-energy Gamma-Ray Radiation from the Crab Pulsar Wind Nebula
• Detection of Small Flares from the Crab Nebula with Fermi-LAT
• Modeling the broadest spectral band of the Crab nebula and constraining the ions acceleration efficiency
• Investigating the multiband nonthermal emission of the 100 TeV source eHWC J2019$+$368 with a pulsar wind nebula scenario
• LHAASO J2226+6057 as a pulsar wind nebula

Cited by in corpus (2)

• Prospects for gamma-ray emission from magnetar regions in CTAO observations
• The expected potential of hadronic PeVatron searches with spectral $\gamma$-ray data from the Southern Wide-field Gamma-ray Observatory