Testing Theories of Gravitation Using 21Year Timing of Pulsar Binary J1713+0747
Abstract
We report 21year timing of one of the most precise pulsars: PSR J1713+0747. Its pulse times of arrival are well modeled by a comprehensive pulsar binary model including its threedimensional orbit and a noise model that incorporates short and longtimescale correlated noise such as jitter and red noise. Its timing residuals have weighted root mean square ∼92 ns. The new data set allows us to update and improve previous measurements of the system properties, including the masses of the neutron star (1.31 ± 0.11 M_{☉}) and the companion white dwarf (0.286 ± 0.012 M_{☉}) as well as their parallax distance 1.15 ± 0.03 kpc. We measured the intrinsic change in orbital period, {\dot{P}}_{{{b}}}^{{Int}}, is 0.20 ± 0.17 ps s^{1}, which is not distinguishable from zero. This result, combined with the measured {\dot{P}}_{{{b}}}^{{Int}} of other pulsars, can place a generic limit on potential changes in the gravitational constant G. We found that \dot{G}/G is consistent with zero [(0.6 ± 1.1) × 10^{12} yr^{1}, 95% confidence] and changes at least a factor of 31 (99.7% confidence) more slowly than the average expansion rate of the universe. This is the best \dot{G}/G limit from pulsar binary systems. The {\dot{P}}_{{{b}}}^{{Int}} of pulsar binaries can also place limits on the putative coupling constant for dipole gravitational radiation {κ }_{{{D}}}=(0.9+/ 3.3)× {10}^{4} (95% confidence). Finally, the nearly circular orbit of this pulsar binary allows us to constrain statistically the strongfield postNewtonian parameters ∆, which describes the violation of strong equivalence principle, and {\hat{α }}_{3}, which describes a breaking of both Lorentz invariance in gravitation and conservation of momentum. We found, at 95% confidence, {{∆ }}\lt 0.01 and {\hat{α }}_{3}\lt 2× {10}^{20} based on PSR J1713+0747.
 Publication:

The Astrophysical Journal
 Pub Date:
 August 2015
 DOI:
 10.1088/0004637X/809/1/41
 arXiv:
 arXiv:1504.00662
 Bibcode:
 2015ApJ...809...41Z
 Keywords:

 binaries: general;
 gravitation;
 parallaxes;
 pulsars: individual: PSR J1713+0747;
 stars: neutron;
 Astrophysics  Solar and Stellar Astrophysics;
 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 14 pages, 6 figures. Published on ApJ, 809, 41 (2015)