The TeV Sun Rises: Discovery of Gamma rays from the Quiescent Sun with HAWC

Abstract

We report the first detection of a TeV gamma-ray flux from the solar disk (6.3$\sigma$), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5--2.6 TeV spectrum is well fit by a power law, dN/dE = $A(E/1\text{ TeV}{)}^{-\gamma }$, with $A=(1.6\pm 0.3)\times 10^{-12}$ TeV${}^{-1}$ cm${}^{-2}$ s${}^{-1}$ and $\gamma =-3.62\pm 0.14$. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

15 pages, 8 figures including supplementary material. Accepted for publication in Physical Review Letters

References in corpus (12)

• Fermi-LAT Observations of Two Gamma-Ray Emission Components from the Quiescent Sun
• Gamma-ray emission from the solar halo and disk: a study with EGRET data
• Gamma-rays from halos around stars and the Sun
• The High-Altitude Water Cherenkov (HAWC) Observatory in México: The Primary Detector
• All-Sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field
• TeV emission of Galactic plane sources with HAWC and H.E.S.S
• A survey of active galaxies at TeV photon energies with the HAWC gamma-ray observatory
• StellarICS: Inverse Compton Emission from the Quiet Sun and Stars from keV to TeV
• Probing the Sea of Cosmic Rays by Measuring Gamma-Ray Emission from Passive Giant Molecular Clouds with HAWC
• Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun
• The solar disk at high energies
• Search for gamma-ray emission from the Sun during solar minimum with the ARGO-YBJ experiment

Cited by in corpus (10)

• Small-Scale Magnetic Fields are Critical to Shaping Solar Gamma-Ray Emission
• Yet Another Sunshine Mystery: Unexpected Asymmetry in GeV Emission from the Solar Disk
• Role of magnetic arcades in explaining the puzzle of the gamma-ray emission from the solar disk
• Super-Kamiokande Strongly Constrains Leptophilic Dark Matter Capture in the Sun
• Revisiting the propagation of highly-energetic gamma rays in the Galaxy
• Prospects for the detection of Dark Matter with Long-lived Mediators in the Sun using the Southern Wide-field Gamma-ray Observatory
• Puzzling Variation of Gamma Rays from the Sun over the Solar Cycle Revealed with Fermi-LAT
• Solar gamma ray probe of local cosmic ray electrons
• First Observations of Solar Halo Gamma Rays Over a Full Solar Cycle
• The influence of the Sun and Moon on the observation of very high energy gamma-ray sources using EAS arrays