Unpulsed radio emission from pulsars

We have searched for unpulsed radio emission from 25 pulsars. Four of these pulsars were found to exhibit a significant unpulsed flux, the ratio of the peak flux to unpulsed flux (beaming ratio) lying between 55 and 2300; for the others we find lower limits for the beaming ratio ranging from 40 to 16000. For the pulsar PSR 1929 + 10 we also demonstrate that the unpulsed flux comes from a region within about 105 km of the neutron star. A possible correlation between the level of unpulsed flux and the orthogonal component of the pulsar magnetic dipole moment implies that the pulsars with detectable unpulsed flux may be those in which the magnetic dipole is nearly aligned with the rotation axis. We also report two previously undetected pulsed features: one situated at a longitude of 120° relative to the main pulse in the integrated profile of PSR 1929 + 10, and the other at a longitude of 225° in the integrated profile of PSR 1818–04.