Pointlike gamma ray sources as signatures of distant accelerators of ultrahigh energy cosmic rays

Phys Rev Lett. 2005 Dec 16;95(25):251102. doi: 10.1103/PhysRevLett.95.251102. Epub 2005 Dec 15.

Abstract

We discuss the possibility of observing distant accelerators of ultrahigh energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photopion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be pointlike, steady, and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level.