Compact steep-spectrum sources and the unified scheme.
- 5 December 1995
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 92 (25) , 11417-11421
- https://doi.org/10.1073/pnas.92.25.11417
Abstract
The compact steep-spectrum sources (CSSs) are an interesting class of objects which are of subgalactic dimensions; they occur more frequently in high-frequency surveys because their spectra often turn over at lower frequencies. We have estimated the symmetry parameters of a well-defined sample of CSSs and compared these with the larger 3CR sources of similar luminosity to understand the evolution and the consistency of CSSs with the unified scheme. We suggest that the majority of CSSs are likely to be young sources advancing outward through an asymmetric, inhomogeneous environment to form the larger ones. The radio properties of the CSSs are consistent with the unified scheme, where the axes of the quasars are seen closer to the line of sight while the radio galaxies lie closer to the plane of the sky. We discuss how radio polarization observations may be used to probe whether the physical conditions in the central regions of the CSSs are different from the larger ones. We present a simple scenario where the depolarization and high rotation measures seen in many CSSs can be consistent with the low rotation measures of cores in the more extended quasars and suggest further observations to test this scenario.Keywords
This publication has 4 references indexed in Scilit:
- Evolution of powerful extragalactic radio sources.Proceedings of the National Academy of Sciences, 1995
- Difficulties with unification.Proceedings of the National Academy of Sciences, 1995
- The case for unification.Proceedings of the National Academy of Sciences, 1995
- Very-long-baseline radio interferometry surveys of the compact structure in active galactic nuclei.Proceedings of the National Academy of Sciences, 1995