A UNIFIED PICTURE FOR HIGH-ENERGY EMISSION IN SPIN-POWERED PULSARS

Based on recent studies of soft gamma-rays from PSR B1509-58, stability of the X-ray pulse from the Crab pulsar, and the interpulse emission from the Crab pulsar, a unified picture for high-energy emission in spin-powered pulsars is proposed. The picture assumes that pulsed X-rays and gamma-rays are emitted both from the polar cap and outer gap regions. We then note that the luminosity and characteristic energy of emitted X-rays and gamma-rays are expected to scale differently to the pulsar parameters, because the relevant physics processes are different in the two regions. We assume two baseline emissions, the Crab broad interpulse emission for the polar cap region and the Vela double peak emission for the outer gap region, and we scale them to predict high-energy emissions from other pulsars. The luminosity and energy range of the predicted pulsed emissions agree reasonably well with observations for PSR B1509-58: the observed broad X-ray/soft gamma-ray emission comes from the polar cap region, while the double peak emission expected from the outer gap region is probably too faint for EGRET to observe. A broad polar cap emission is predicted for the Vela pulsar in the MeV range at a luminosity between the Crab interpulse and the broad PSR B1509-58 pulse.