2010/04/30 by Charles D. Dermer, Soebur Razzaque · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Blazar #Cosmic ray #Extragalactic background light #Fermi Gamma-ray Space Telescope #Fermi acceleration #Galaxy #Gamma-ray bursts and supernovae #Lorentz factor #Neutrino Physics Research #Particle acceleration #Radio galaxy #Spitzer Space Telescope #astro-ph.HE #hep-ph
paper · pdf · doi:10.1088/0004-637x/724/2/1366
published as Astrophys.J.724:1366-1372,2010 · 8 pages, 3 figures, ApJ, in press
arxiv created 2010/09/27 · openalex publication_date 2010/11/12 · arxiv updated 2010/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Fermi Gamma-ray Space Telescope measurements of spectra, variability timescales, and maximum photon energies give lower limits to the apparent jet powers and, through γγ opacity arguments, the bulk Lorentz factors of relativistic jets. The maximum cosmic-ray particle energy is limited by these two quantities in Fermi acceleration scenarios. Recent data are used to constrain the maximum energies of cosmic-ray protons and Fe nuclei accelerated in colliding shells of gamma-ray bursts (GRBs) and blazars. The Fermi results indicate that Fe rather than protons are more likely to be accelerated to ultra-high energies in active galactic nuclei (AGNs), whereas powerful GRBs can accelerate both protons and Fe to ≳10 20 eV. Emissivity of nonthermal radiation from radio galaxies and blazars is estimated from the First Fermi AGN Catalog, and shown to favor BL Lac objects and FR1 radio galaxies over flat spectrum radio quasars, FR2 radio galaxies, and long-duration GRBs as the sources of ultra-high-energy cosmic rays.