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Register a new userPSR J1829+2456: a relativistic binary pulsar
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D. J. Champion
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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 advance of periastron, omegadot = 0.28 +/- 0.01 deg/yr is derived from our timing observations spanning 200 days. Assuming that the advance of periastron is purely relativistic and a reasonable range of neutron star masses for PSR J1829+2456 we constrain the companion mass to be between 1.22 Msun and 1.38 Msun, making it likely to be another neutron star. We also place a firm upper limit on the pulsar mass of 1.38 Msun. The expected coalescence time due to gravitational-wave emission is long (~60 Gyr) and this system will not significantly impact upon calculations of merger rates that are relevant to upcoming instruments such as LIGO.
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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 not explicitly accounted for in a deterministic model. Nevertheless, the physically important astrometric, spin, and orbital parameters are well determined and well decoupled from the timing noise. We have determined a significant result for proper motion, $mu_{alpha} = -1.43pm0.13$, $mu_{delta}=-0.70pm0.13$ mas yr$^{-1}$. The pulsar exhibited a small timing glitch in May 2003, with ${Delta f}/f=3.7times10^{-11}$, and a smaller timing peculiarity in mid-1992. A relativistic solution for orbital parameters yields improved mass estimates for the pulsar and its companion, $m_1=1.4398pm0.0002 M_{sun}$ and $m_2=1.3886pm0.0002 M_{sun}$. The systems orbital period has been decreasing at a rate $0.997pm0.002$ times that predicted as a result of gravitational radiation damping in general relativity. As we have shown before, this result provides conclusive evidence for the existence of gravitational radiation as predicted by Einsteins theory.
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