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Precision Pulsar Timing in the Presence of Interstellar Weather – PSR B1937+21 and the Crab Pulsar

Published online by Cambridge University Press:  12 April 2016

D. C. Backer
Affiliation:
Astronomy Department, University of California at Berkeley
T. Wong
Affiliation:
Astronomy Department, University of California at Berkeley

Abstract

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We report on six months of dual-frequency, precision timing of PSR B1937+21 and the Crab pulsar. Variations in the column density of electrons – interstellar weather – are studied. The column is not unique in the presence of frequency-dependent multipath scattering, and this may explain the non-square law dependence of systematic timing residuals on B1937+21. The electron column density variations of the Crab pulsar are summarized in a structure function that ranges from 1012 cm to 1015 cm. These density fluctuations are located in the thermal shell surrounding the synchrotron nebula.

Type
Part 2 Precision Measurements
Copyright
Copyright © Astronomical Society of the Pacific 1996

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