2013MNRAS.431.2580L

We reproduce the broad-band spectrum of Crab pulsar, from ultraviolet (UV) to very high energy gamma-rays - nearly ten decades in energy, within the framework of the cyclotron-self-Compton model. Emission is produced by two counter-streaming beams within the outer gaps, at distances above ∼ 20 NS radii. The outward moving beam produces UV-X-ray photons via Doppler-booster cyclotron emission, and GeV photons by Compton scattering the cyclotron photons produced by the inward going beam. The scattering occurs in the deep Klein-Nishina regime, whereby the inverse Compton (IC) component provides a direct measurement of particle distribution within the magnetosphere. The required plasma multiplicity is high, ∼ 106-107, but is consistent with the average particle flux injected into the pulsar wind nebula.

The importance of Compton scattering in the Klein-Nishina regime also implies the importance of pair production in the outer gaps. We suggest that outer gaps are important sources of pairs in pulsar magnetospheres.

Cyclotron motion of particles in the pulsar magnetosphere may be excited due to coherent emission of radio waves by streaming particles at the anomalous cyclotron resonance. Thus, a whole range of Crab non-thermal emission, from coherent radio waves to very high energy gamma-rays - nearly eighteen decades in energy - may be a manifestation of inter-dependent radiation processes.

The present model, together with the observational evidence in favour of the IC scattering, demonstrates that the IC scattering can be the dominant high-energy emission mechanism in majority of pulsars.