Polarized Gamma-Ray Emission from the Crab
A. J. Dean,1
D. J. Clark,1
J. B. Stephen,2
V. A. McBride,1
L. Bassani,2
A. Bazzano,3
A. J. Bird,1
A. B. Hill,1
S. E. Shaw,1
P. Ubertini3
Pulsar systems accelerate particles to immense energies. The detailed functioning of these engines is still poorly understood, but polarization measurements of high-energy radiation may allow us to locate where the particles are accelerated. We have detected polarized gamma rays from the vicinity of the Crab pulsar using data from the spectrometer on the International Gamma-Ray Astrophysics Laboratory satellite. Our results show polarization with an electric vector aligned with the spin axis of the neutron star, demonstrating that a substantial fraction of the high-energy electrons responsible for the polarized photons are produced in a highly ordered structure close to the pulsar.
1 School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK.
2 Istituto Nazionale di Astrofisica–Istituto di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF), Via Piero Gobetti 101, 40129 Bologna, Italy.
3 INAF-IASF, Via Fosso del Cavaliere 100, 00133 Roma, Italy.
