2005/12/31 by Roman R. Rafikov, Dong Lai · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Geophysics and Gravity Measurements #Pulsars and Gravitational Waves Research #Stellar, planetary, and galactic studies #astro-ph #gr-qc
paper · pdf · doi:10.1103/physrevd.73.063003
published as Phys.Rev.D73:063003,2006 · Minor changes, accepted to Phys. Rev. D
arxiv created 2006/02/21 · openalex publication_date 2006/03/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The measurement of the Shapiro time delay in binary pulsar systems with highly-inclined orbit can be affected both by the motion of the pulsar's companion because of the finite time it takes a photon to cross the binary, and by the gravitational light bending if the orbit is sufficiently edge-on relative to the line of sight. Here we calculate the effect of retardation due to the companion's motion on various time delays in pulsar binaries, including the Shaipro delay, the geometric lensing delay, and the lens-induced delays associated with the pulsar rotation. Our results can be applied to systems so highly inclined that near conjunction gravitational lensing of the pulsar radiation by the companion becomes important (the recently discovered double pulsar system J0737-3039 may exemplify such a system). To the leading order, the effect of retardation is to shift all the delay curves backward in time around the orbit conjunction, without affecting the shape and amplitude of the curves. The time shift is of order the photon orbit crossing time, and ranges from a second to a few minutes for the observed binary pulsar systems. In the double pulsar system J0737-3039, the motion of the companion may also affect the interpretation of the recent correlated interstellar scintillation measurements. Finally, we show that lensing sets an upper limit on the magnitude of the frame-dragging time delay caused by the companion's spin, and makes this delay unobservable in stellar-mass binary pulsar systems.