Pulsed optical emission by radio pulsars

The luminosity L of radio pulsars due to synchrotron radiation by the primary beam at the magnetosphere periphery is derived. There is a strong correlation between the observed optical luminosities of radio pulsars and the parameter P(overdot)/P-4 (where P is the pulsar period). This correlation predicts appreciable optical emission from several dozen pulsars, in particular, from all those with P < 0.1 s. Agreement with optical observations can be achieved for Lorentz factors of the secondary plasma gamma (p) = 2-13. Plasma with such energies can be produced only when the magnetic-field structure near the neutron-star surface deviates substantially from a dipolar field. The peak frequency of the synchrotron spectrum should shift toward higher values as the pulsar period P decreases this is, in agreement with observational data for 27 radio pulsars for which emission has been detected outside the radio band. (C) 2001 MAIK " Nauka/lnterperiodica".