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General Relativistic Precession of the Spin Axis of Binary Pulsar B1913+16: First Two Dimensional Maps of the Emission Beam

Published online by Cambridge University Press:  12 April 2016

Joel M. Weisberg
Affiliation:
Department of Physics and Astronomy, Carleton College, Northfield, MN, 55057USA
Joseph H. Taylor
Affiliation:
Department of Physics, Princeton University, Princeton, NJ 08544USA

Abstract

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Relativistic spin-orbit coupling should cause the spin axis of Binary Pulsar B1913+16 to precess at a rate of about 1 deg / yr. As a result, the pulse profile is expected to exhibit secular evolution. Weisberg, Romani, & Taylor (1989), and Weisberg & Taylor (1992) found that the intensity ratio of the two conal components changed at a one percent per year rate from 1981 to 1989, but that their spacing did not measurably change. They attributed these observations to our line of sight passing across the middle of a patchy cone of emission. Recently Kramer (1998) found that the intensity ratio continued its secular change for another decade, and also detected a narrowing of the conal component separation.

We present our analysis of eighteen years of 21 cm pulse profile data. We confirm that the profile is narrowing as precession finally carries our line of sight away from the emission beam axis, and we map the beam in two dimensions. The beam is elongated in the latitude direction, and the degree of elongation grows with radius.

Type
Part 2. Timing, General Relativity and Astrometry
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

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