Speaker
Description
The active phase of jetted AGN can last several tens or hundreds of Myr, after which the radio jets cease and the source begins to fade. This so-called remnant plasma provides a unique opportunity to constrain jet activity timescales - a key parameter in feedback models - and to study the long-term impact of AGN on their surrounding environment. Historically elusive, these sources are now being revealed in larger numbers by low-frequency surveys with SKA precursors and pathfinders. Despite this progress, systematic selection remains challenging.
In this talk, I will present recent advances in the field, focusing on our new systematic search for remnant radio galaxies in the LoTSS HETDEX field at 150 MHz. Using a semi-automatic approach, we have identified the largest sample to date, with over 100 candidate sources. I will discuss the methods and challenges involved in identifying these complex objects and how this sample can be leveraged to train machine learning algorithms to expand the search. Finally, I will show how the observed properties of this sample can be interpreted within the framework of radio galaxy population models and hydrodynamical simulations. This study lays the groundwork for the first statistical investigation of remnant radio galaxies and highlights the discovery potential of future SKA surveys.