DOI

https://doi.org/10.48717/xbrp-qr85

Project

ES101

Title

Old radio activity in two young radio galaxies

Abstract

The first phase of evolution of radio galaxies is represented by sources with compact sizes and peaked radio spectra. Radio observations at high angular resolution usually resolve the radio source in a symmetric structure, which resembles a scaled down version of a Classical Double. In a simple scenario they are expected to grow, expand beyond the ISM of the host galaxy and become large radio galaxies (FRI/FRII). This seems indeed an oversimplification, and the radio AGN phenomenon is likely a periodic phase in the evolution of an AGN, with multiple cycles of activity, and possibly some false starts before the full development of the radio source. Here we propose to observe with EVN+eMERLIN the only two clear examples of young radio sources with an indication of an active radio AGN at the mas scale, and diffuse unrelated radio emission at the same scale, possibly from an earlier phase of activity, or from a different mechanism with respect to the radio emission produced by jets. Observations at 1.7 GHz will characterize the structure of the diffuse radio emission at an unprecedented sensitivity from the millliarcsecond to the arcsecond scale.