Is the Galactic Cosmic Ray Spectrum Constant in Time?

TL;DR

This paper explores whether the Galactic cosmic ray spectrum varies over time due to source intermittency, proposing that underground muogenic nuclide measurements could reveal the time-averaged spectrum and impact predictions of high-energy emissions.

Contribution

It introduces the idea that source intermittency affects the cosmic ray spectrum and suggests underground measurements as a new method to determine the time-averaged spectrum.

Findings

Source intermittency may explain low anisotropy observed by IceCube.

Predictions for ultrahigh-energy emissions could be significantly affected.

The hypothesis offers a new perspective on cosmic ray spectrum variability.

Abstract

The hypothesis is considered that the present Galactic cosmic ray spectrum is at present softer than its time average due to source intermittency. Measurements of muogenic nuclides underground could provide an independent measurement of the time averaged spectrum. Source intermittency could also account for the surprising low anisotropy reported by the IceCube collaboration. Predictions for Galactic emission of ultrahigh-energy quanta, such as UHE gamma rays and neutrinos, might be higher or lower than previously estimated.