Probing the environments surrounding ultrahigh energy cosmic ray accelerators and their implications for astrophysical neutrinos

Understand

We explore inferences on ultrahigh energy cosmic ray (UHECR) source environments -- constrained by the spectrum and composition of UHECRs and non-observation of extremely high energy neutrinos -- and their implications for the observed high energy astrophysical neutrino spectrum.

• We find acceleration mechanisms producing power-law CR spectra~$\propto E^{-2}$ are compatible with UHECR data, if CRs at high rigidities are in the quasi-ballistic diffusion regime as they escape their source environment.
• Both gas-dominated and photon-dominated source environments are able to account for UHECR observations, however photon-dominated sources give a better fit.
• Additionally, gas-dominated sources are in tension with current neutrino constraints.