English

Outer gap accelerator closed by magnetic pair-creation process

High Energy Astrophysical Phenomena 2017-02-22 v1

Abstract

We discuss outer gap closure mechanism in the trans-field direction with the magnetic pair-creation process near the stellar surface. The gap closure by the magnetic pair-creation is possible if some fraction of the pairs are produced with an outgoing momentum. By assuming that multiple magnetic field will affect the local field near the stellar surface, we show a specific magnetic field geometry near the stellar surface resulting in the outflow of the pairs. Together with the fact that the electric field is weak below null charge surface, the characteristic curvature photon energy emitted by incoming particles, which were accelerated in the outer gap, decreases drastically to 100\sim 100MeV near the stellar surface. We estimate the height measured from the last-open field line, above which 100MeV photons is converted into pairs by the magnetic pair-creation. We also show the resultant multiplicity due to the magnetic pair-creation process could acquire Me±104105M_{e^{\pm}}\sim 10^4-10^5. In this model the fractional outer gap size is proportional to P1/2P^{-1/2}. The predicted gamma-ray luminosity (LγL_{\gamma}) and the characteristic curvature photon energy (EcE_c) emitted from the outer gap are proportional to B2P5/2B^2P^{-5/2} and B3/4P1B^{3/4}P^{-1} respectively. This model also predicts that LγL_{\gamma} and EcE_c are related to the spin down power (LsdL_{sd}) or the spin down age of pulsars (τ\tau) as LγLsd5/8L_{\gamma} \propto L_{sd}^{5/8} or Lγτ5/4L_{\gamma} \propto \tau^{-5/4}, and EcLsd1/4E_c \propto L_{sd}^{1/4} or Ecτ1/2E_c \propto \tau^{-1/2} respectively.

Keywords

Cite

@article{arxiv.1004.1243,
  title  = {Outer gap accelerator closed by magnetic pair-creation process},
  author = {J. Takata and Y. Wang and K. S. Cheng},
  journal= {arXiv preprint arXiv:1004.1243},
  year   = {2017}
}

Comments

33 pages, 9 figures, Accepted for publication in ApJ.

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