Modeling the multiwavelength light curves of PSR B1259-63/LS 2883. II. the effects of anisotropic pulsar wind and Doppler boosting

Abstract

PSR B1259-63/LS 2883 is a binary system in which a 48ms pulsar orbits around a Be star in a high eccentric orbit with a long orbital period of about 3.4yr. It is special for having asymmetric two-peak profiles in both the X-ray and TeV light curves. Recently, an unexpected GeV flare has been detected by the Fermi gamma-ray observatory several weeks after the last periastron passage. In this paper, we show that this observed GeV flare could be produced by the Doppler-boosted synchrotron emission in the bow-shock tail. An anisotropic pulsar wind model, which mainly affects the energy flux injection into the termination shock in a different orbital phase, is also used in this paper, and we find that the anisotropy in the pulsar wind can play a significant role in producing the asymmetric two-peak profiles in both X-ray and TeV light curves. The X-ray and TeV photons before periastron are mainly produced by the shocked electrons around the shock apex, and the light curves after periastron are contributed by the emission from the shock apex and the shock tail together, which result in asymmetric two-peak light curves. © 2012. The American Astronomical Society. All rights reserved..