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M. A. Teter, G. G. Pavlov, D. Sanwal, O. Kargaltsev (Penn State University)
Observations of the Vela pulsar-wind nebula (PWN) with Chandra have revealed a long, thin filament -- an extension of the pulsar's jet beyond the bright outer arc confining the PWN in the direction of the pulsar's proper motion. This curved external jet terminates in a region of enhanced emission (a blob) at a distance of about 100'' (0.15 pc) from the pulsar, larger than the size of the PWN. The shape of the jet and its brightness are seen to vary on a timescale as short as a few days, its remote parts move in the sky plane with apparent velocities of up to 0.2 c. The X-ray spectrum of the external jet, including the termination blob, shows no spectral features. It is well described by a power-law model with a photon-index of \gamma ~q 1.2 (slightly harder than the average spectrum of the PWN, \gamma ~q 1.5). This indicates that the jet's radiation is due to synchrotron emission of relativistic particles in a magnetic field. The fact that the jet remains confined, although it twists at large distances from the pulsar, suggests a self-confining structure of its magnetic field. The varying shape and intensity of this stream of relativistic particles can be associated with varying local conditions in the Vela SNR and/or large-scale MHD instabilities and internal variations of the magnetic field within the jet.
We will present a movie with a sequence of 12 Chandra images over past two years, demonstrating the structure of the twisting jet, and discuss various interpretations of these observations.
The work was partially supported by SAO grant GO2-3091X and NASA grant NAG5-10865.
The author(s) of this abstract have provided an email address for comments about the abstract: teter@astro.psu.edu
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.