The origin of cosmic rays: Explosions of massive stars with magnetic winds and their supernova mechanism

TL;DR

This paper investigates the origin of cosmic rays, proposing that supernovae from massive stars with magnetic winds produce specific spectral features, including an upturn at high energies, consistent with observations and supporting a magneto-rotational supernova mechanism.

Contribution

It provides a theoretical prediction of cosmic ray spectra from supernovae with magnetic winds and confirms these predictions with observational data, strengthening the link between such supernovae and cosmic ray origins.

Findings

Observed spectra show an upturn consistent with predictions.

Heavy element spectra support the same rigidity for all elements.

Results favor magneto-rotational supernovae as cosmic ray sources.

Abstract

One prediction of particle acceleration in the supernova remnants in the magnetic wind of exploding Wolf Rayet and Red Super Giant stars is that the final spectrum is a composition of a spectrum $E^{-7/3}$ and a polar cap component of $E^{-2}$ at the source. This polar cap component contributes to the total energy content with only a few percent, but dominates the spectrum at higher energy. The sum of both components gives spectra which curve upwards. The upturn was predicted to occur always at the same rigidity. An additional component of cosmic rays from acceleration by supernovae exploding into the Inter-Stellar Medium (ISM) adds another component for Hydrogen and for Helium. After transport the predicted spectra $J(E)$ for the wind-SN cosmic rays are $E^{-8/3}$ and $E^{-7/3}$; the sum leads to an upturn from the steeper spectrum. An upturn has now been seen. Here, we test the observations against the predictions, and show that the observed properties are consistent with the predictions. Hydrogen can be shown to also have a noticeable wind-SN-component. The observation of the upturn in the heavy element spectra being compatible with the same rigidity for all heavy elements supports the magneto-rotational mechanism for these supernovae. This interpretation predicts the observed upturn to continue to curve upwards and approach the $E^{-7/3}$ spectrum. If confirmed, this would strengthen the case that supernovae of very massive stars with magnetic winds are important sources of Galactic cosmic rays.