THE SYNCHROTRON SELF-COMPTON MODEL FOR X-RAY AND GAMMA-RAY EMISSION FROM PULSARS

We compare the observed X-ray luminosity emitted from pulsars with tha t calculated from various theoretical models and find that the X-ray e mission from six pulsars is much stronger than that predicted by theor etical models. We suggest that these pulsars with unusually intense X- ray emission could also be gamma-ray emitters. Electrons/positrons are accelerated in the outer magnetospheric gap and lose most of their en ergy via curvature radiation (primary photons), which will be converte d to secondary e(+/-) pairs outside the gap in collision with the seco ndary X-rays. A simple synchrotron self-Compton model is then used to calculate the X-ray and gamma-ray emission from the secondary e(+/-) p airs. This model only contains a single free parameter, which characte rizes the size of the acceleration region and can be estimated by comp arison with that of the Crab pulsar. Our model results are consistent with the observed data and upper limits of gamma-ray emission and phas e separation between pulses. Other implications for future observation s are also discussed in the text.