Observe Gamma-Rays and Neutrinos Associated with Ultra-High Energy Cosmic Rays

Abstract

IceCube measures a diffuse neutrino flux comparable to the Waxman-Bahcall bound, which suggests the possibility that the ultra-high energy cosmic rays (UHECRs) have a common origin with diffuse high energy neutrinos. We propose high energy gamma-ray and/or neutrino observations toward the arrival directions of UHECRs to search for the sources and test this possibility. We calculate the detection probability of gamma-ray/neutrino sources, and find that the average probability per UHECR of >10 EeV is $\sim$10% if the sensitivity of the gamma-ray or neutrino telescope is $\sim$10${}^{-12}$ erg cm${}^{-2}$s${}^{-1}$ and the source number density is $\sim$10${}^{-5}$ Mpc${}^{-3}$. Future gamma-ray and neutrino observations toward UHECRs, e.g., by LHAASO-WCDA, CTA, IceCube/Gen2, are encouraged to constrain the density of UHECR sources or even identify the sources of UHECRs.

8 pages, 3 figures

References in corpus (2)

• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• The extragalactic background light revisited and the cosmic photon-photon opacity