The aim of this paper is to study the time delay on electromagnetic signals
propagating across a binary stellar system. We focus on the antisymmetric
gravitomagnetic contribution due to the angular momentum of one of the stars of
the pair. Considering a pulsar as the source of the signals, the effect would
be manifest both in the arrival times of the pulses and in the frequency shift
of their Fourier spectra. We derive the appropriate formulas and we discuss the
influence of different configurations on the observability of gravitomagnetic
effects. We argue that the recently discovered PSR J0737-3039 binary system
does not permit the detection of the effects because of the large size of the
eclipsed region.Comment: 7 pages, 2 eps figures, RevTex, to appear in Physical Review
