摘要
The origin and radiation mechanisms of high-energy emissions from pulsars have remained mysterious since their discovery. Here we report, based on a sample of 68 pulsars, observational connection of non-thermal X-ray emissions from pulsars with their timing properties and thermal emissions, which may provide some constraints on theoretical modeling. Besides strong correlations with the spin-down power E ͘ and the magnetic field strength at the light cylinder B lc , the non-thermal X-ray luminosity in 0.5–8 keV, L p , represented by the power-law component in the spectral model, is found to be strongly correlated with the highest possible electric field strength in the polar gap, E pc , of the pulsar. The spectral power index Γ p of that power-law component is also found, for the first time in the literature, to strongly correlate with E ͘ , B lc , and E pc , thanks to the large sample. In addition, we found that L p can be well described by L p ∝ T 5.96 ± 0.64 R 2.24 ± 0.18 , where T and R are the surface temperature and the emitting-region radius of the surface thermal emission, represented by the blackbody component in the spectral model. Γ p , on the other hand, can be well described only when timing variables are included and the relation is Γ p = log(T −5.8 ± 1.93 R −2.29 ± 0.85 P −1.19 ± 0.88 P ͘0.94 ± 0.44 ) plus a constant. These relations strongly suggest the existence of connections between surface thermal emission and electron–positron pair production in pulsar magnetospheres.