1,726,264 research outputs found
A neutral hydrogen distance limit to the relativistic binary PSR J1141-6545
No full textWe 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 J1141-6545 offers the promise of stringent tests of general relativity (GR) by comparing its observed orbital period derivative with that derived from other relativistic observables. At the distance of PSR J1141-6545 it should be possible to verify GR to an accuracy of just a few per cent, as contributions to the observed orbital period derivative from kinematic terms will be a small fraction of that induced by the emission of gravitational radiation. PSR J1141-6545 will thus make an exceptional gravitational laboratory
Relativistic Spin Precession in the Binary PSR J1141-6545
No full textPSR J1141-6545 is a precessing binary pulsar that has the rare potential to reveal the two-dimensional structure of a non-recycled pulsar emission cone. It has undergone similar to 25 degrees of relativistic spin precession in the similar to 18 yr since its discovery. In this Letter, we present a detailed Bayesian analysis of the precessional evolution of the width of the total intensity profile, in order to understand the changes to the line-of-sight (LOS) impact angle (beta) of the pulsar using four different physically motivated prior distribution models. Although we cannot statistically differentiate between the models with confidence, the temporal evolution of the linear and circular polarizations strongly argue that our LOS crossed the magnetic pole around MJD 54,000 and that only two models remain viable. For both of these models, it appears likely that the pulsar will precess out of our LOS in the next 3-5 yr, assuming a simple beam geometry. Marginalizing over beta suggests that the pulsar is a near-orthogonal rotator and provides the first polarization-independent estimate of the scale factor (A) that relates the pulsar beam opening angle (rho) to its rotational period (P) as rho = AP(-0.5): we find it to be >6 degrees s(0.5) at 1.4 GHz with 99% confidence. If all pulsars emit from opposite poles of a dipolar magnetic field with comparable brightness, we might expect to see evidence of an interpulse arising in PSR J1141-6545, unless the emission is patchy
Geodetic Precession in PSR J1141-6545
No full textWe present observations that show dramatic evolution of the mean pulse profile of the relativistic binary pulsar J1141-6545 over a period of 5 yr. This is consistent with the precession of the pulsar spin axis due to relativistic spin-orbit coupling. Observations made between 1999 and 2004 with a number of instruments at the Parkes radio telescope demonstrate a steady, secular evolution of the mean total intensity profile, which increases in width by more than 50% during the 5 yr period. Analysis of the changing position angle of the linearly polarized component of the mean profile suggests that our line of sight is shifting closer to the core of the emission cone. We find that the slope of the position angle swing across the center of the pulse steepens with time and use a simplified version of the rotating vector model to constrain the magnitude and direction of the change in our line-of-sight angle relative to the pulsar magnetic axis. The fact that we appear to be moving deeper into the emission cone is consistent with the non-detection of this pulsar in previous surveys. © 2005. The American Astronomical Society. All rights reserved
Geodetic precession in PSR J1141-6545
No full textWe present observations that show dramatic evolution of the mean pulse profile of the relativistic binary pulsar J1141-6545 over a period of 5 yr. This is consistent with the precession of the pulsar spin axis due to relativistic spin-orbit coupling. Observations made between 1999 and 2004 with a number of instruments at the Parkes radio telescope demonstrate a steady, secular evolution of the mean total intensity profile, which increases in width by more than 50% during the 5 yr period. Analysis of the changing position angle of the linearly polarized component of the mean profile suggests that our line of sight is shifting closer to the core of the emission cone. We find that the slope of the position angle swing across the center of the pulse steepens with time and use a simplified version of the rotating vector model to constrain the magnitude and direction of the change in our line-of-sight angle relative to the pulsar magnetic axis. The fact that we appear to be moving deeper into the emission cone is consistent with the nondetection of this pulsar in previous surveys
Self-consistency of Relativistic Observables with General Relativity in the White Dwarf-Neutron Star Binary PSR J1141-6545
No full textHere we report timing measurements of the relativistic binary PSR J1141-6545 that constrain the component masses and demonstrate that the orbital period derivative Pb = (-4 ± 1) × 10-13 is consistent with gravitational wave emission as described by the general theory of relativity. The mass of the neutron star and its companion are 1.30 ± 0.02 and 0.986 ± 0.02 M⊙, respectively, suggesting a white dwarf companion and extending the range of systems for which general relativity provides a correct description. On evolutionary grounds, the progenitor mass of PSR J1141-6545 should be near the minimum for neutron star production. Its mass is 2 standard deviations below the mean of the other neutron stars, suggesting a relationship between progenitor and remnant masses
Self-consistency of relativistic observables with general relativity in the white dwarf-neutron star binary PSR J1141-6545
No full textHere we report timing measurements of the relativistic binary PSR J1141-6545 that constrain the component masses and demonstrate that the orbital period derivative Pb=(-4+/-1)×10-13 is consistent with gravitational wave emission as described by the general theory of relativity. The mass of the neutron star and its companion are 1.30+/-0.02 and 0.986+/-0.02 Msolar, respectively, suggesting a white dwarf companion and extending the range of systems for which general relativity provides a correct description. On evolutionary grounds, the progenitor mass of PSR J1141-6545 should be near the minimum for neutron star production. Its mass is 2 standard deviations below the mean of the other neutron stars, suggesting a relationship between progenitor and remnant masses
TEAL 6545
No full textThe learning objectives for TEAL 6545 are to develop a research question about a chosen topic and to design a realistic study to conduct in the future. This library module teaches viewers about research and resources including strategies, grey literature, peer review, and more.
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Gravitational-radiation losses from the pulsar-white-dwarf binary PSR J1141-6545
No full textPulsars in close binary systems with white dwarfs or other neutron stars make ideal laboratories for testing the predictions of gravitational radiation and self-gravitational effects. We report new timing measurements of the pulsar–white-dwarf binary PSR J1141–6545. The orbit is found to be decaying at a rate of 1.04±0.06 times the general relativistic prediction and the Shapiro delay is consistent with the orbital inclination angle derived from scintillation measurements. The system provides a unique testbed for tensor-scalar theories of gravity. Our measurements place stringent constraints in the theory space, with a limit of alpha02<2.1×10-5 for weakly nonlinear coupling and an asymptotic limit of alpha02<3.4×10-6 for strongly nonlinear coupling (where alpha0 is the linear coupling strength of matter to an underlying scalar field), which is nearly 3 times smaller than the Cassini bound (alpha02[approximate]10-5)
The scintillation velocity of the relativistic binary pulsar PSR J1141-6545
No full textWe 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 the 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 (~115 km s-1) or a more face-on binary with a much slower velocity (~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 76deg+/-2.5d, implying a companion mass of 1.01+/-0.02 Msolar and a pulsar mass of 1.29+/-0.02 Msolar. Our derived physical parameters indicate that this pulsar should prove to be an excellent laboratory for tests of gravitational wave emission
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