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P. Demorest, R. Ramachandran, D. Backer (UC Berkeley), R. Ferdman, I. Stairs (UBC), D. Nice (Princeton)
High-precision pulsar timing is a unique and useful tool for many different scientific applications, including studies of the interstellar medium, relativistic binary systems, and long period gravitational wave studies. Our group has designed and installed a new generation of pulsar instrumentation at several radio observatories over the past year: The Arecibo Signal Processor (ASP), the Green Bank Astronomical Signal Processor (GASP), and the Berkeley-Orleans-Nancay processor (BON). These machines perform real time coherent dedispersion of the pulsar signal on up to 64 MHz of bandwidth, and quasi-real time up to 128 MHz. They use high dynamic range voltage sampling (8 bits), which significantly reduces digitization artifacts. The processing is done in an array of personal computers, which makes the machines extremely flexible for future development.
We present preliminary results from several different studies using this new instrumentation. At Green Bank, we have initiated a program of long-term precision timing of 15 pulsars using the 100m Green Bank Telescope. The data from this project will be used to study binary systems, and contribute to the ongoing multi-observatory effort to create a Pulsar Timing Array - a group of many pulsars distributed about the sky which can be used to detect gravitational radiation with a period of 1-10 years. We also have continuous use of a 85ft telescope at Green Bank which we have used to study dispersion measure fluctuations of PSR B1937+21 on timescales of 1 day to several years. These fluctuations are a potential systematic effect for the gravity wave study, and also help us learn more about the nature of interstellar weather.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.