ON THE SPECTRUM OF THE PULSED GAMMA-RAY EMISSION OF THE CRAB PULSAR FROM 10 MeV TO 400 GeV

Abstract

In the present paper, a self-consistent theory, interpreting VERITAS and the MAGIC observations of the very high-energy pulsed emission from the Crab pulsar, is considered. The photon spectrum between 10 MeV and 400 GeV can be described by two power-law functions with spectral indices of 2.0 and 3.8. The source of the pulsed emission above 10 MeV is assumed to be 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 Lorentz factors up to 10 9 . Such high energies of beam particles can be reached due to Landau damping of the Langmuir waves in the light cylinder region.

Detection of bridge emission above 50 GeV from the Crab pulsar with the MAGIC telescopes

“…Arka & Dubus (2013) demonstrated that a sufficient luminosity and a hard spectrum extending to 100 GeV can be obtained for P1 and P2 via the synchrotron emission by a hot plasma from the current sheet slightly outside the LC, but in this scenario the bridge emission should disappear above 10 GeV. Chkheidze et al (2013) proposed that synchrotron radiation generated near the LC during the quasi-linear stage of the cyclotron instability can produce the phase-aligned pulsation between radio and γ-rays. However, the formation of a bridge component is not explained in this model.…”

Detection of VHE Bridge emission from the Crab pulsar with the MAGIC Telescopes

“…There are several models which can explain the VHE emission of the Crab pulsar, such as Aleksić et al [2011], Aharonian et al [2012], Bednarek [2012], Arka and Dubus [2013], Chkheidze et al [2013]. However, none of them can explain the VHE pulse profile and the spetrum consistently.…”

Energy accumulation mechanism in pulsar magnetospheric plasma eigen-waves and formation of Giant Radio Pulses

“…One more fact in favor of our model is the nondetection of correlation of GRPs and emission in higher frequencies (Shearer et al 2003). The mechanism of generation of high frequency emission in pulsars differs from that of radio emission (see Chkheidze et al (2013)) and is connected with the appearance of pitch angles due to development of cyclotron-Cherenkov and Cherenkov-drift resonances, switching on the synchrotron emission generation mechanism. The high frequency emission fulfills λ ≪ n −1/3 condition leaving the generation region freely without taking part in any process of energy accumulation by waves.…”