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We report a dramatic orbital modulation in the scintillation timescale of the relativistic binary pulsar J1141--6545 that both confirms the validity of the scintillation speed methodology and enables us to derive important physical parameters. We have determined the space velocity, the orbital inclination and even the longitude of periastron of the binary system, which we find to be in good agreement with that obtained from pulse timing measurements. Our data permit two equally-significant physical interpretations of the system. The system is either an edge-on binary with a high space velocity ($sim 115$ km s$^{-1}$) or is more face-on with a much slower velocity ($sim 45$ km s$^{-1}$). We favor the former, as it is more consistent with pulse timing and the distribution of known neutron star masses. Under this assumption, the runaway velocity of 115 km s$^{-1}$ is much greater than is expected if pulsars do not receive a natal kick at birth. The derived inclination of the binary system is (76pm 2.5^{circ}) degrees, implying a companion mass of 1.01 (pm )~0.02 M(_{odot}) and a pulsar mass of 1.29 (pm)~0.02 M(_{odot}). Our derived physical parameters indicate that this pulsar should prove to be an excellent laboratory for tests of gravitational wave emission.
We have obtained an HI absorption spectrum of the relativistic binary PSR J1141-6545 and used it to constrain the distance to the system. The spectrum suggests that the pulsar is at, or beyond, the tangent point, estimated to be at 3.7 kpc. PSR J1141
The binaries PSR J1141-6545 and PSR B2303+46 each appear to contain a white dwarf which formed before the neutron star. We describe an evolutionary pathway to produce these two systems. In this scenario, the primary transfers its envelope onto the se
Pulsars in close binary systems have provided some of the most stringent tests of strong-field gravity to date. The pulsar--white-dwarf binary system J1141-6545 is specifically interesting due to its gravitational asymmetry which makes it one of the
We present results of more than three decades of timing measurements of the first known binary pulsar, PSR B1913+16. Like most other pulsars, its rotational behavior over such long time scales is significantly affected by small-scale irregularities n
We report the discovery of a new binary pulsar, PSR J1829+2456, found during a mid-latitude drift-scan survey with the Arecibo telescope. Our initial timing observations show the 41-ms pulsar to be in a 28-hr, slightly eccentric, binary orbit. The ad