Green Bank Telescope observations of the eclipse of pulsar "A" in the double pulsar binary PSR J0737-3039

We report on the first Green Bank Telescope observations at 427, 820, and 1400 MHz of the newly discovered, highly inclined, and relativistic double pulsar binary. We focus on the brief eclipse of PSR J0737-3039A, the faster pulsar, when it passes behind PSR J0737-3039B. We measure a frequency-averaged eclipse duration of 26.6 +/- 0.6 s or 0.00301 +/- 0.00008 in orbital phase. The eclipse duration is found to be significantly dependent on radio frequency, with eclipses longer at lower frequencies. Specifically, eclipse duration is well fitted by a linear function having slope (-4.52 +/- 0.03) x 10(-7) orbits MHz(-1). We also detect significant asymmetry in the eclipse. Eclipse ingress takes 3.51 +/- 0.99 times longer than egress, independent of radio frequency. In addition, the eclipse lasts (40 +/- 7) x 10(-5) in orbital phase longer after conjunction, also independent of frequency. We detect significant emission from the pulsar on short timescales during eclipse in some orbits. We discuss these results in the context of a model in which the eclipsing material is a shock-heated plasma layer within the slower PSR J0737-3039B's light cylinder, where the relativistic pressure of the faster pulsar's wind confines the magnetosphere of the slower pulsar.