Oct 8 – 12, 2018
Ecole Supérieure de Chimie, Paris
Europe/Paris timezone

Particle Acceleration in Radio Galaxies

Oct 9, 2018, 9:00 AM
Friedel Amphitheater (Ecole Supérieure de Chimie, Paris)

Friedel Amphitheater

Ecole Supérieure de Chimie, Paris

Chimie ParisTech École Nationale Supérieure de Chimie de Paris 11, rue Pierre et Marie Curie 75231 PARIS Cedex 05
INVITED Sessions


Prof. Tony Bell (University of Oxford)


Ultra-high energy cosmic rays pose an extreme challenge to theories of particle acceleration. We discuss the reasons why diffusive acceleration by shocks is a leading contender. A crucial aspect of shock acceleration is that cosmic rays must be efficiently scattered by magnetic field. This requires magnetic field amplification on scales comparable with the cosmic ray Larmor radius, which in turn indicates that the shocks cannot be fully relativistic; nor can the shocks be too slow. The lower limit, arising from the Hillas condition, on the energy processed in the shock severely restricts the range of possible sources of UHECR. These conditions combine to make the lobes of radio galaxies a likely source of UHECR.

Primary authors

Prof. Tony Bell (University of Oxford) Dr James Matthews (University of Oxford) Prof. Katherine Blundell (University of Oxford) Dr Anabella Araudo (Astronomical Institute, Czech Academy of Sciences)

Presentation materials