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Radio Observations of Moderately Compact Steep Spectrum Sources

Published online by Cambridge University Press:  07 August 2017

Chidi Akujor
Affiliation:
Astrophysics Group, University of Nigeria, Nsukka, Nigeria N.R.A.L., Jodrell Bank, U.K.
I.W.A. Browne
Affiliation:
Nuffield Radio Astronomy Laboratories, Jodrell Bank, U.K.
P.N. Wilkinson
Affiliation:
Nuffield Radio Astronomy Laboratories, Jodrell Bank, U.K.

Extract

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It is now common practice for objects with a steep radio spectrum and compact radio structure to be lumped together and called compact steep spectrum (CSS) sources (Peacock and Wall, 1982; van Breugel, 1984 Fanti et al. 1985). This rather arbitrary categorisation results in the class containing sources with a wide range of structures, from core-jet or complex (e.g. 3C147,3C48), small classical doubles (e.g. 3C237, 3C241), to VLBI compact doubles (e.g. CTD93; Phillips and Mutel, 1982). Some of the questions we are asking include:

  1. (a) Are compact sources intrinsically small, or do they appear small because they are seen in projection?

  2. (b) Why are structures in compact radio galaxies and compact radio quasars different? Wilkinson et al. (1984) and Spencer et al (1988, in preparation)have shown that there appears to be a ‘clear-cut’ difference in morphology between quasar CSS and galaxy CSS, with quasars showing more distortions while galaxies tend to be doubles. But is this trend present even in their slightly more-extended counterparts?

Type
Part 10: Radio Galaxies, Components and Structure
Copyright
Copyright © Kluwer 1989 

References

Peacock, J. and Wall, J.V. 1982. M.N.R.A.S., 198, 843 Google Scholar
Phillips, R.B. and Mutel, R.L., 1982. Astron.Astrophys., 106, 21 Google Scholar
van Breugel, W., 1984. in Fanti, R. et al.(eds), VLBI and Compact Radio Sources, D. Reidel, p.59 Google Scholar
Wilkinson, P.N. et al., 1984 in Fanti, R. et al (eds), VLBI and Compact Radio Sources, D. Reidel, p.25 Google Scholar