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Non-constant Superluminal Velocities in AGN

Published online by Cambridge University Press:  25 April 2016

Colin S. Coleman
Colin S. Coleman*
Affiliation:
Department of Mathematics, Monash University, Clayton, Vic 3168
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Abstract

Large apparent superluminal velocities are observed in nuclear jets in Active Galaxies, indicating the presence of relativistic velocities almost along the line of sight. If the flow is well collimated, as suggested by the large scale radio structure, the inferred alignment leads to difficulties with source statistics. Here a modification of the usual relativistic beam model is proposed, in which the jet is assumed to contain azimuthal (swirling) flow. Perturbation analysis is used to show that the jet is unstable to a Kelvin-Helmholtz helical standing wave, the wavelength of which increases without bound in the limit of vanishing swirl. This instability may cause a cylindrical jet to follow a helical path in space, thereby reducing the implied alignment of a superluminal source, and providing a natural interpretation of non-constant superluminal velocities.

Type
Extragalactic
Information
Publications of the Astronomical Society of Australia , Volume 8 , Issue 4 , 1990 , pp. 353 - 356
Copyright
Copyright © Astronomical Society of Australia 1990

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References

Begelman, M.C., Blandford, R. D. and Rees, M. J., 1984, Rev. Mod. Phys., 56, 255.CrossRefGoogle Scholar
Benford, G., 1981, Astrophys. J., 247, 792.Google Scholar
Biretta, J. A., Cohen, M. H., Unwin, S. C. and Pauliny-Toth, I. I.K., 1983, Nature, 306, 42.Google Scholar
Blandford, R. D., McKee, C. F. and Rees, M. J., 1977, Nature, 267, 211.Google Scholar
Blandford, R. D. and Rees, M. J., 1974, Mon. Not. R. Astron. Soc., 169, 395.Google Scholar
Broadbent, E. G. and Moore, D. W., 1979, Phil. Trans. Roy. Soc. Lond. A., 290, 353.Google Scholar
Broadbent, E. G., 1984, Proc. Roy. Soc. Lond. A., 392, 279.Google Scholar
Coleman, C.S., 1989, Proc. Astron. Soc. Aust., 8, 38.CrossRefGoogle Scholar
Coleman, C. S., 1990, Mon. Not. R. Astron. Soc., (in press).Google Scholar
Ferrari, A., Massaglia, S. and Trussoni, E., 1982, Mon. Not. R. Astron. Soc., 198, 1065.Google Scholar
Ferrari, A., Trussoni, E. and Zaninetti, L., 1978, Astron. Astrophys., 64, 43.Google Scholar
Ferrari, A., Trussoni, E. and Zaninetti, L., 1981, Mon. Not. R. Astron. Soc., 196, 1051.Google Scholar
Gill, A. E., 1965, Phys. Fluids, 8, 1428.Google Scholar
Hardee, P. E., 1979, Astrophys. J., 234, 47.Google Scholar
Moore, R.L., Readhead, A. C. S. and Baath, L., 1983, Nature, 306, 44.Google Scholar
Ray, T. P., 1982, Mon. Not. R. Astron. Soc., 198, 617.CrossRefGoogle Scholar
Rees, M. J., 1966, Nature, 211, 468.Google Scholar
Schilizzi, R. T. and de Bruyn, A. G., 1983, Nature, 303, 26.Google Scholar
Unwin, S. C, Cohen, M. H., Pearson, T. J., Seielstad, G. A., Simon, R. S., Linfleld, R. P. and Walker, R. C, 1983, Astrophys. J., 271, 536.Google Scholar