The Mean Pulse Profile of PSR J0737-3039A

General relativity predicts that the spin axes of the pulsars in the double-pulsar system PSR J0737-3039A/B will precess rapidly, in general leading to a change in the observed pulse profiles. We have observed this system over a 1 yr interval using the Parkes 64 m radio telescope at three frequencies: 680, 1390, and 3030 MHz. These data, combined with the short survey observation made 2 years earlier, show no evidence for significant changes in the pulse profile of PSR J0737-3039A, the 22 ms pulsar. The limit on variations of the profile 10% width is about 0°50 yr-1. These results imply an angle δ between the pulsar spin axis and the orbit normal of ≤60°, consistent with recent evolutionary studies of the system. Although a wide range of system parameters remain consistent with the data, the model recently proposed by F. A. Jenet & S. M. Ransom can be ruled out. A nonzero ellipticity for the radiation beam gives slightly but not significantly improved fits to the data, so that a circular beam describes the data equally well within the uncertainties. © 2005. The American Astronomical Society. All rights reserved.