Radio Source Evolution on Galactic Scales

TL;DR

This paper extends existing models of radio source evolution to include young, small-scale sources, accounting for radiative losses, and predicts their observable properties and evolution over approximately 100 million years.

Contribution

It introduces a physically-motivated model for young radio sources that incorporates radiative losses and detailed expansion dynamics, improving upon previous models.

Findings

Young radio sources undergo significant radiative losses.

Model predictions align with observed Compact Steep-Spectrum sources.

Complete evolution from cocoon formation to source end is modeled.

Abstract

There is mounting evidence that mechanical radio source feedback is important in galaxy evolution and in order to quantify this feedback, detailed models of radio source evolution are required. We present an extension to current analytic models that encompasses young radio sources with physical sizes on sub-kiloparsec scales. This work builds on an existing young source dynamical model to include radiative losses in a flat environment, and as such, is the best physically-motivated Compact Symmetric Object model to date. Results predict that young radio sources experience significant radiative loss on length scales and spectral scales consistent with observed Compact Steep-Spectrum sources. We include full expressions for the transition to self-similar expansion and present this complete model of radio source evolution from first cocoon formation to end of source lifetime around 10^8 years within the context of a simplified King profile external atmosphere.