Prof Joel Weisberg (ATNF & Sydney University Visiting Scientist, on leave from Carleton College, USA)

Testing General Relativity and Pulsar Physics with Binary Pulsar B1913+16 - Prof Joel Weisberg Colloquium

ATNF Marsfield Lecture Theatre

Abstract

I will describe results derived from thirty years of observations of the excellent relativity laboratory, binary pulsar PSR B1913+16. The measured rate of change of orbital period agrees with that expected from the emission of gravitational
radiation, according to general relativity, to within about 0.2
percent. Measurements of the relativistic periastron advance and a combination of gravitational redshift and time dilation yield the masses of the two stellar components with high accuracy. Geodetic precession of
the pulsar spin axis leads to secular changes in pulse shape as the
pulsar-observer geometry changes. This effect makes it possible to
model the two-dimensional structure of the beam, whereas ordinary pulsar
observations yield only a one-dimensional cut. We find that the
beam is elongated in the latitude direction and appears to be
pinched in longitude near its center. I will discuss prospects for additional progress with future observations.