Studying the highly bent spectra of FR II-type radio galaxies with the KDA EXT model

TL;DR

This study applies the KDA EXT model to aged FR II radio galaxies with bent spectra, demonstrating it predicts observed spectra more accurately than the original KDA model.

Contribution

The paper introduces and tests the KDA EXT model for aged FR II radio sources, showing improved spectral predictions over the classical KDA approach.

Findings

KDA EXT model fits observed spectra better than KDA model.

The model accurately predicts spectral bending at high frequencies.

Results support the use of KDA EXT for aged radio galaxy analysis.

Abstract

The KDA (Kaiser, Dennett-Thorpe & Alexander, 1997) EXT model, that is, the extension of the KDA model of FR (Faranoff & Riley) II-type source evolution, is applied and confronted with the observational data for selected FR II-type radio sources with significantly aged radio spectra. A sample of FR II-type radio galaxies with radio spectra strongly bent at their highest frequencies is used for testing the usefulness of the KDA EXT model.The dynamical evolution of FR II-type sources predicted with the KDA EXT model is briefly presented and discussed. The results are then compared to the ones obtained with the classical KDA approach, assuming the source's continuous injection and self-similarity. The results and corresponding diagrams obtained for the eight sample sources indicate that the KDA EXT model predicts the observed radio spectra significantly better than the best spectral fit provided by the original KDA model.