Comparison of the parameters of radio-quiet and radio-loud gamma-ray pulsars

The periods, period derivatives, surface magnetic fields, magnetic fields near the light cylinder, and rates of loss of rotational energy for two groups of gamma-ray pulsars are compared, for which radio emission has and has not been detected. The mean values of these parameters are similar for the two groups, but their distributions differ. For example, in the radio-loud objects, the magnetic field at the light cylinder BLC displays a nearly Gaussian distribution, while this distribution is nearly uniform for the radio-quiet group. As a rule, the radio-loud group has higher values of BLC. A correlation between the gammaray luminosity of the pulsars and BLC is found, suggesting that the radiation is generated near the light cylinder, probably due to the synchrotron mechanism.