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M.A. Livingstone, V.M. Kaspi, F.P. Gavriil (McGill), R.N. Manchester (ATNF)
Pulsar braking indices are only measurable for the very youngest of objects. In all cases, values less than 3 (for magnetic dipole radiation) have been reported. Due in large part to contamination from timing noise, values of the braking index or the second braking index for several of these objects have been called into question. We present an updated timing solution for the young, energetic pulsar PSR~B1509-58 based on 21.3~years of radio timing data and 7.6~years of data from the Rossi X-ray Timing Explorer. We have measured the braking index using fully and partially phase-coherent timing analyses to show that despite scatter due to timing noise, the braking index is constant to within 1.5% over the entire time span. We have also measured the second braking index to be consistent with the dipolar model of pulsar spin-down. In addition, we present initial results for a new timing analysis of the `Crab twin' pulsar, PSR~B0540-69. Using archival RXTE data, we use similar methods to those used in the analysis of PSR~B1509-58 to measure a braking index.
The author(s) of this abstract have provided an email address for comments about the abstract: maggie@physics.mcgill.ca
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.