A spectral analysis of two compact steep-spectrum sources

We have added new high-resolution VLA and VLBA data of two compact steep-spectrum sources (CSSs) (3C 67 and 3C 190) to existing data. We find both sources have a complex spectral structure that is not completely resolved with these data. A standard aging analysis of 3C 190 predicts an unusually steep injection index of -0.8 and a young age. If CSSs are found to have steep injection indices in general, then it suggests that they are not simply younger, smaller versions of large radio sources,but a different type of object. Another possibility is that the injection index is -0.5 and that the superposition of aged spectral components makes the injection index appear steeper. Whichever explanation is appropriate, interpretation of spectral data in such conventional terms as aging must be made cautiously.