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The Crab pulsar echoes

Published online by Cambridge University Press:  12 April 2016

F. Graham Smith
Affiliation:
Jodrell Bank Observatory, Macclesfield, Cheshire, SK11 9DL, UK
A.G. Lyne
Affiliation:
Jodrell Bank Observatory, Macclesfield, Cheshire, SK11 9DL, UK

Abstract

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Observations over an eight month period from July 1997 to March 1998 show echoes following the radio pulses, and unusual changes in dispersion measure. We interpret this remarkable and complex event as refraction and dispersion in an ionised shell in the outer part of the Crab Nebula. The shell is remarkably compact; it has a electron density of about 103 – 104 cm−3 and a thickness of about 3 × 1011m. Similar events have been noticed on several other occasions during the continuous monitoring of the Crab pulsar over the past 25 years.

Type
Part 7. The Surrounding of Pulsars
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

Backer, D.C. 2000, in Proc. IAU Coll. 177, PASP, eds. Kramer, M., Wex, N., Wielebinski, R. Google Scholar
Hester, J.J., et al. 1993, ApJ, 448, 240 Google Scholar
Lyne, A.G., Pritchard, R.S., Graham, Smith F., 1992, MNRAS, 265, 1003 Google Scholar
Lyne, A.C., Thorne, D.J. 1975., MNRAS, 172, 97 Google Scholar
Wyckhoff, S., Murray, C.A 1977, MNRAS, 180, 717 CrossRefGoogle Scholar