Department of Physics and Astronomy: Publications and Other Research
Date of this Version
2007
Abstract
Cosmic rays are particles and nuclei that bombard the Earth from space in all directions (1). A few have astounding energies—beyond 100 EeV (1 EeV = 1 exa-electron volt = 1018 eV)—orders of magnitude beyond even the future capabilities of any earthly particle accelerator. Such energies are so extreme that they could arise in only the most violent places in the universe. One possible location is within active galactic nuclei (AGN), galaxies hosting central black holes that feed on gas and stars and may eject vast plasma jets into intergalactic space.
Comments
Published in SCIENCE VOL 318. 9 NOVEMBER 2007.www.sciencemag.org