Solar gamma ray probe of local cosmic ray electrons

Abstract

TeV-range cosmic ray electrons and positrons (CREs) have been directly measured in the search for new physics or unknown astrophysical sources. CREs can inverse-Compton scatter solar photons and boost their energies into gamma ray bands. Any potential CRE excess would enhance the resultant inverse Compton emission spectrum in the relevant energy range, offering a new window to verify the measured CRE spectrum. In this paper, we show that an excess in the TeV range of the CRE spectrum, such as the one indicated by the DAMPE experiment, can induce a characteristic solar gamma ray signal. Accounting for contamination from extragalactic gamma ray backgrounds (EGB), we forecast the DAMPE feature is testable ($\gtrsim 4\sigma$) with a $\sim 10^5{\mathrm{m}}^2\mathrm{yr}$ exposure in the off-disk direction. This can be achieved by long-exposure observations of water Cherenkov telescopes, such as LHAASO (7.2 years) and HAWC (25.9 years).

arXiv comment6 pages, 4 figures

References in corpus (17)

• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons
• Sensitivity of the High Altitude Water Cherenkov Detector to Sources of Multi-TeV Gamma Rays
• Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope
• Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station
• Fermi-LAT Observations of Two Gamma-Ray Emission Components from the Quiescent Sun
• A Predictive Analytic Model for the Solar Modulation of Cosmic Rays
• Gamma-ray emission from the solar halo and disk: a study with EGRET data
• Gamma-rays from halos around stars and the Sun
• A model explaining neutrino masses and the DAMPE cosmic ray electron excess
• First HAWC Observations of the Sun Constrain Steady TeV Gamma-Ray Emission
• The TeV Sun Rises: Discovery of Gamma rays from the Quiescent Sun with HAWC
• DAMPE squib? Significance of the 1.4 TeV DAMPE excess
• StellarICS: Inverse Compton Emission from the Quiet Sun and Stars from keV to TeV
• Implications of dark matter cascade decay from DAMPE, HESS, Fermi-LAT and AMS02 data
• The Southern Wide-Field Gamma-ray Observatory (SWGO)
• Transport of Cosmic ray electrons from 1 AU to the Sun