Engine-driven Relativistic Supernovae as Sources of Ultra High Energy Cosmic Rays

TL;DR

This paper investigates engine-driven relativistic supernovae, specifically SN 2009bb, as potential sources of ultra-high-energy cosmic rays, by analyzing radio spectra to assess their energetic capabilities and magnetic field evolution.

Contribution

It provides detailed measurements of SN 2009bb's properties, demonstrating that engine-driven supernovae can accelerate particles beyond the GZK limit, suggesting they are viable UHECR sources.

Findings

SN 2009bb's size-magnetic field evolution measured

Engine-driven SNe lie above the Hillas line

Can explain characteristics of post-GZK UHECRs

Abstract

Understanding the origin of the highest energy cosmic rays is a crucial step in probing new physics at energies unattainable by terrestrial accelerators. Their sources remain an enigma half a century after their discovery. They must be accelerated in the local universe as otherwise interaction with cosmic background radiations would severely deplete the flux of protons and nuclei at energies above the Greisen-Zatsepin-Kuzmin (GZK) limit. Hypernovae, nearby GRBs, AGNs and their flares have all been suggested and debated in the literature as possible sources. Type Ibc supernovae have a local sub-population with mildly relativistic ejecta which are known to be sub-energetic GRBs or X-Ray Flashes for sometime and more recently as those with radio afterglows but without detected GRB counterparts, such as SN 2009bb. In this work we measure the size-magnetic field evolution, baryon loading and energetics of SN 2009bb using its radio spectra obtained with VLA and GMRT. We show that the engine-driven SNe lie above the Hillas line and they can explain the characteristics of post-GZK UHECRs.