1998AJ....116.1984W

We have developed a method to explore the detailed structure of the mean pulse profile of pulsars–namely, the Gaussian fit separation of the average profile (GFSAP) method–in which we model the total profile as a superposition of several Gaussian-shaped components. PSR B1451-68 has been observed at six frequencies, 170, 271, 400, 649, 950, and 1612 MHz, providing an excellent basis for a multifrequency analysis. Applying the GFSAP method to PSR 1451-68's ostensibly triple profile, we find strong evidence that it has five components in its profile. Based on this and other evidence, we conclude that PSR 1451-68 must be a member of the five-component (M) species. Benefiting from the separation, we are able to discuss the geometric properties of the three distinct emission zones: the core, the inner cone, and the outer cone. The first implies an inclination angle of 38°, and the 1 GHz widths of the conal radii are compatible with those found in 1993 by Rankin for the pulsar population at large. The radius of the outer cone increases markedly with decreasing frequency. Finally, the spectrum of the core component exhibits a strong break near 800 MHz and, probably, a turnover at about 150 MHz. At low frequency the core component dominates the pulsar's emission, whereas at high frequency the inner conal component pair is the strongest contributor to the emission.