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.

arXiv comment15 pages, 8 figures including supplementary material. Accepted for publication in Physical Review Letters

References in corpus (34)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory
• Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC
• 3HWC: The Third HAWC Catalog of Very-High-Energy Gamma-ray Sources
• Observation of TeV Gamma Rays from the Crab Nebula with Milagro Using a New Background Rejection Technique
• Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC
• Fermi-LAT Observations of Two Gamma-Ray Emission Components from the Quiescent Sun
• Powerful Solar Signatures of Long-Lived Dark Mediators
• Gamma-ray emission from the solar halo and disk: a study with EGRET data
• All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV
• Solar Atmospheric Neutrinos: A New Neutrino Floor for Dark Matter Searches
• The High-Altitude Water Cherenkov (HAWC) Observatory in México: The Primary Detector
• Gamma-rays from halos around stars and the Sun
• Neutrinos from cosmic ray interactions in the Sun
• All-Sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field
• Constraints on Spin-Dependent Dark Matter Scattering with Long-Lived Mediators from TeV Observations of the Sun with HAWC
• First Observation of Time Variation in the Solar-Disk Gamma-Ray Flux with Fermi
• Solar Atmospheric Neutrinos and the Sensitivity Floor for Solar Dark Matter Annihilation Searches
• Evidence for a New Component of High-Energy Solar Gamma-Ray Production
• Search for Very High Energy Gamma Rays from the Northern $\text{Fermi}$ Bubble Region with HAWC
• Unexpected Dip in the Solar Gamma-Ray Spectrum
• TeV Solar Gamma Rays From Cosmic-Ray Interactions
• Cosmic-ray interactions with the Sun using the FLUKA code
• First HAWC Observations of the Sun Constrain Steady TeV Gamma-Ray Emission
• 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
• Measurements of the Time-Dependent Cosmic-Ray Sun Shadow with Seven Years of IceCube Data -- Comparison with the Solar Cycle and Magnetic Field Models
• StellarICS: Inverse Compton Emission from the Quiet Sun and Stars from keV to TeV
• The Sun at TeV energies: gammas, neutrons, neutrinos and a cosmic ray shadow
• Constraining the $\bar{p}/p$ Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC
• 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