Numerical treatment of annual modulation of relic neutrinos

Abstract: We present a numerical treatment of the annual modulation of relic neutrinos due to the Sun's gravitational influence. Extending our previously developed N-1-body simulation framework from Milky Way scales to solar system dynamics, we model how cosmic neutrino background densities might vary throughout Earth's orbital cycle. We validate our numerical approach against analytical expectations from previous studies that assumed idealized relic neutrino populations. Our results suggest that the prior gravitational history of neutrinos traversing asymmetric dark matter distributions can affect annual modulation patterns. While our simulations reproduce modulation amplitudes similar to analytical predictions for heavier neutrinos, we find that the amplitude can vary considerably depending on the specific morphology of dark matter halos. These findings highlight the importance of incorporating realistic structure formation effects when predicting potential observational relic neutrino signatures.