Ja n 20 04 Green Bank Telescope Observations of the Eclipse of Pulsar “ A ” in the Double Pulsar Binary PSR J 0737 − 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 at superior conjunction, when it passes behind PSR J0737−3039B. We measure a frequency-averaged eclipse duration of 27.4 ± 1.3 s, or 0.00310 ± 0.00015 in orbital phase. Given the relative transverse velocity of the pulsars at conjunction of 680 km s, this implies that the eclipsing region has size 18,600 km, or 0.063 lt-s. The eclipse duration is independent of frequency to within our measurement uncertainties. We place a 99% confidence upper limit on the absolute value of a frequency power-law index of eclipse duration of 0.46. We detect significant asymmetry in the eclipse. Specifically, eclipse ingress takes 4.0 ± 1.3 times longer than egress. There is evidence that the eclipse lasts longer and is deeper after conjunction. 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. Subject headings: pulsars: general — pulsars: individual (PSR J0737−3039) — binaries: eclipsing — binaries: general — stars: neutron Department of Physics, Rutherford Physics Building, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, Canada Department of Physics and Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 Canada Research Chair; NSERC Steacie Fellow Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, CA 94720 Theoretical Astrophysics Center and Physics Department, University of California, 601 Campbell Hall, Berkeley, CA 94720 KIPAC, Stanford University, P.O. Box 20450, MS 29, Stanford, CA 94309 Chandra Fellow