Evidence for the existence of gravitational radiation from measurements of the binary pulsar PSR 1913+16

Results of four years of timing observations of PSR 1913+16 made with the 305-m telescope at the Arecibo Observatory at frequencies near 430 and 1410 MHz are summarized. Received intensity data were accumulated for intervals of 5 minutes and the resulting profile was then fitted to a template to determine its precise arrival time. Data on PSR 1913+16 have been acquired using a number of different receivers, dispersion-removing systems, and recording methods in order to improve the measurement accuracy. Random errors in the measured pulse arrival times have been reduced from 300 microseconds in 1974 to 50 microseconds in 1978. Analysis of the timing data was carried out using a model which describes the system in terms of 13 parameters of physical interest. It is found that changes of the orbital period observed during the experiment can be best explained by gravitational radiation damping at a rate consistent with the predictions of general relativity