Synchrotron emission model of gamma-ray pulsar PSR J2021+3651

Abstract

In the present paper a self-consistent theory, interpreting the high energy gamma-ray and X-ray observations of pulsar PSR J2021+3651 performed by Fermi-LAT, XMM-Newton and Chandra space telescopes are considered. It is shown that the photon spectrum between 0.1 keV and 25 GeV can be well described by a power-law function with the spectral index Γ ≈ 1.4 and the exponential cutoff, with the cutoff energy ɛ₀ ≈ 2 GeV. The source of the pulsed emission above 0.1 keV is assumed to be the synchrotron radiation, which is generated near the light cylinder during the quasi-linear stage of the cyclotron instability. The emitting particles are the primary beam electrons with the Lorentz factors γ_b ∼^{10 6 - 7} . The generation of the radio emission observed from this source is provided due to plasma collective processes that excite the low frequency cyclotron modes in the radio domain.