Astron. Astrophys. 363, 575-584 (2000)

The optical, X-ray and gamma-ray light curves and spectra of crab-like pulsars: PSR B0540-69 and PSR B1509-58

L. Zhang ^1,2 and K.S. Cheng <sup>1

1</sup> The University of Hong Kong, Department of Physics, P.R. China
² Yunnan University, Department of Physics, Kunming, P.R. China

Received 25 January 2000 / Accepted 17 August 2000

Abstract

Based on the three dimensional outer magnetosphere model of pulsars proposed by Cheng, Ruderman and Zhang, we calculate the light curves and spectra of the Crab-like pulsars: PSR B0540-69 and PSR B1509-58. In this model, thermal photon emission from the entire stellar surface is due to the bombardment of the backflow charged particles from the outer gap and cyclotron resonance scattering (Cheng & Zhang 1999). Non-thermal photons are emitted by pairs produced by backflow charged particles from the outer gap through a synchrotron radiation mechanism near the stellar surface and in a finite region just above the outer gap through a synchrotron self-Compton mechanism. For PSR B1509-58, when the magnetic inclination and viewing angle are and respectively, the photon emission region has a mean thickness of , where is the radius of the light cylinder. The expected broad single pulse in optical, X-ray and -ray energy bands are comparable with the observed light curves with a correct phase off-set with respect to the radio pulse, and the model spectrum is consistent with the observed spectrum. For PSR B0540-69, the calculated mean thickness of the photon emission region is and the model light curve and spectrum are similar to the observed data if the magnetic inclination and viewing angle are and respectively.

Key words: stars: pulsars: individual: PSR B0540-69 stars: pulsars: individual: PSR B1509-58 gamma rays: theory X-rays: stars

Send offprint requests to: L. Zhang

© European Southern Observatory (ESO) 2000

Online publication: December 11, 2000

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