Mode changing and quasi-periodic modulation in pulsar 1737+13, a bright, five-componented pulsar

PSR 1737 + 13 is a bright, recently discovered pulsar with five distinct components in its average profile. The few stars with five-component profiles (the "multiple" or M species in the classification scheme published by Rankin in 1983) have much in common, but only one such star, 1237+25, has been analyzed in detail. We have thus studied pulsar 1737+ 13 in an effort to better define the characteristics of the group. The two stars are found to resemble each other in many respects. Not only are their profiles and the frequency evolution of their profiles similar, but they exhibit many similar modulation, mode-changing, and polarization-mode phenomena. Our study of 1737+13 has strengthened our belief that the five-component stars of the multiple (M) species represent a well-differentiated class, and that the group is important because they manifest the full range of phenomena of which the pulsar emission process is capable.