2006/10/30 by Caroline D’Angelo, Caroline D'Angelo, Roman R. Rafikov · 3 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Binary number #Computational physics #Geophysics and Gravity Measurements #Gravitational wave #Millisecond pulsar #Neutron star #Physics #Pulsar #Pulsars and Gravitational Waves Research #RADIUS #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1103/physrevd.75.042002
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 75(4) (American Physical Society) · 12 pages, 3 figures, submitted to Physical Review D
arxiv created 2006/10/30 · openalex publication_date 2007/02/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Precision timing is the key ingredient of ongoing pulsar-based gravitational wave searches and tests of general relativity using binary pulsars. The conventional approach to timing explicitly assumes that the radio emitting region is located at the center of the pulsar, while polarimetric observations suggest that radio emission is in fact produced at altitudes ranging from tens to thousands of kilometers above the neutron star surface. Here we present a calculation of the effects of finite emission height on the timing of binary pulsars using a simple model for the emitting region geometry. A finite height of emission h changes the propagation path of radio photons through the binary and gives rise to a large spin velocity of the emission region corotating with the neutron star. Under favorable conditions these two effects introduce corrections to the conventional time delays at the microsecond level (for a millisecond pulsar in a double neutron star binary with a period of several hours and assuming h=100 km). Exploiting the dependence of the emission height on frequency (radius-to-frequency mapping) and using multifrequency observations one should be able to detect these timing corrections even though they are formally degenerate with conventional time delays. Although even in the most accurately timed systems the magnitude of the finite emission height effects is currently somewhat below timing precision, longer-term observations and future facilities like SKA will make measurement of these effects possible, providing an independent check of existing emission height estimates.