Long-term Radio Timing Observations of PSR B1509 58

Margaret A. Livingstone, Victoria M. KaspiMcGill University, 3600 University Ave, Montreal, Quebec, Canada.H3A 2T8.Richard N. ManchesterAustralia Telescope National Facility, CSIRO, P.O. Box 76, EppingNSW 1710, AustraliaAbstract. We present an updated phase-coherent timing solution forthe young, energetic pulsar PSR B1509−58 for twenty years of data.Using a partially phase-coherent timing analysis, we show that the sec-ond frequency derivative is changing in time implying a third frequencyderivative of