Ultra High Energy Cosmic Ray Acceleration in Engine-driven Relativistic Supernovae

TL;DR

This paper investigates how engine-driven relativistic supernovae, particularly SN 2009bb, can accelerate cosmic rays to ultra-high energies, potentially explaining the origins of the highest energy cosmic rays observed.

Contribution

It demonstrates that certain engine-driven supernovae can accelerate cosmic rays beyond the GZK limit, providing a new candidate source for ultra-high energy cosmic rays.

Findings

SN 2009bb's radio spectra reveal size-magnetic field evolution.

Engine-driven SNe can surpass the Hillas line for cosmic ray acceleration.

These supernovae can explain post-GZK ultra-high energy cosmic rays.

Abstract

The origin of the highest energy cosmic rays remains an enigma. They offer a window to new physics, including tests of physical laws relevant to their propagation and interactions, at energies unattainable by terrestrial accelerators. They must be accelerated locally, as otherwise background radiations would severely suppress the flux of protons and nuclei, at energies above the Greisen-Zatsepin-Kuzmin (GZK) limit. Nearby Gamma Ray Bursts (GRBs), Hypernovae, Active Galactic Nuclei (AGNs) and their flares, have all been suggested and debated as possible sources. A local sub-population of type Ibc supernovae (SNe) with mildly relativistic outflows have been detected as sub-energetic GRBs or X-Ray Flashes (XRFs) and recently as radio afterglows without detected GRB counterparts. We measure the size-magnetic field evolution, baryon loading and energetics, using the observed radio spectra of SN 2009bb. We place such engine-driven SNe above the Hillas line and establish that they can readily explain the post-GZK UHECRs.