Testing Theories of Gravitation Using 21-Year Timing of Pulsar Binary J1713+0747

Abstract

We report 21-year 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 three-dimensional orbit and a noise model that incorporates short-and long-timescale 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 e ) and the companion white dwarf (0.286 ± 0.012 M e ) as well as their parallax distance 1.15 ± 0.03 kpc. We measured the intrinsic change in orbital period, P b Inṫ , is −0.20 ± 0.17 ps s −1 , which is not distinguishable from zero. This result, combined with the measured P bInṫ of other pulsars, can place a generic limit on potential changes in the gravitational constant G. We found that G Ġ 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 G Ġ limit from pulsar binary systems. The P b Inṫ of pulsar binaries can also place limits on the putative coupling constant for dipole gravitational radiation 0.9 3.3 10´-(95% confidence). Finally, the nearly circular orbit of this pulsar binary allows us to constrain statistically the strong-field post-Newtonian parameters Δ, which describes the violation of strong equivalence principle, and 3 a , which describes a breaking of both Lorentz invariance in gravitation and conservation of momentum. We found, at 95% confidence, 0.01 D < and 2 10 3 20 a <´-based on PSR J1713+0747.

A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

“…Given the 7.6 year interval between the events we observed, if the events were periodic, the previous event would have been at 2011.2. However, no such event is evident in the timeseries of Zhu et al (2015). We note a low-significance DM dip event in that data set in early 2002, but it is far from the predicted time.…”

“…To check for periodicities of such structures, we examined the DDMtimeseries of Zhu et al (2015) for PSRJ1713+0747, which extends back to 1998. Given the 7.6 year interval between the events we observed, if the events were periodic, the previous event would have been at 2011.2.…”

Variability, polarimetry, and timing properties of single pulses from PSR J1713+0747 using the Large European Array for Pulsars

“…Most recent timing analysis has started to take into account the effect of phase jitter when modelling the noise in the timing data (e.g. Lentati & Shannon 2015;Zhu et al 2015;Caballero et al 2016). Detailed studies of single pulse variability in MSPs are crucial for building a comprehensive understanding of this phenomenon, if we are to push beyond this limitation.…”

“…This pulsar is one of the most precisely timed pulsars and has been included in current pulsar timing array campaigns to detect gravitational waves in the nanohertz frequency range . The binary system it inhabits is also an ideal test laboratory for alternative theories of gravity (Zhu et al 2015). Edwards & Stappers (2003) showed that there is clear modulation in the pulses from PSR J1713+0747 and that it varies across the pulse profile and as a function of observing frequency.…”

First Search for Nontensorial Gravitational Waves from Known Pulsars

“…However, pulsar orientations can also be inferred from other measurements, especially if the object is in a binary (e.g., Refs. [39][40][41]). We will consider incorporating such constraints in future searches.…”