GAUSSIAN COMPONENT DECOMPOSITION AND THE 5-COMPONENT PROFILE OF PULSAR 1451-68

We have developed a method to explore the detailed structure of the me an 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 h as been observed at six frequencies, 170, 271, 400, 649, 950, and 1612 MHz, providing an excellent basis for a multifrequency analysis. Appl ying the GFSAP method to PSR 1451-68's ostensibly triple profile, we f ind 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 mem ber 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 fir st implies an inclination angle of 38 degrees, 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 increase s markedly with decreasing frequency. Finally, the spectrum of the cor e component exhibits a strong break near 800 MHz and, probably, a turn over at about 150 MHz. At low frequency the core component dominates t he pulsar's emission, whereas at high frequency the inner conal compon ent pair is the strongest contributor to the emission.