A LOFAR view on the duty cycle of young radio sources

TL;DR

This study uses LOFAR's high sensitivity to investigate the duty cycle of young radio sources by searching for extended, low-brightness emission around compact sources, shedding light on their evolutionary history.

Contribution

It presents a systematic LOFAR-based approach to detect extended emission around young radio sources, providing new insights into their activity cycles and evolution.

Findings

Detection of extended emission around some CSS, GPS, and HFP sources.

Identification of a CSS source with surrounding diffuse lobes, indicating past activity.

Enhanced understanding of the duty cycle and lifecycle of young radio sources.

Abstract

Compact Steep Spectrum, Gigahertz Peaked Spectrum and High Frequency Peak (CSS, GPS, HFP) sources are considered to be young radio sources but the details of their duty cycle are not well understood. In some cases they are thought to develop in large radio galaxies, while in other cases their jets may experience intermittent activity or die prematurely and remain confined within the host galaxy. By studying in a systematic way the presence and the properties of any extended emission surrounding these compact sources we can provide firmer constraints on their evolutionary history and on the timescales of activity of the radio source. Remnant emission from previous outbursts is supposed to have very low surface brightness and to be brighter at low frequency. Taking advantage of the unprecedented sensitivity and resolution provided by the Low Frequency Array (LOFAR) we have started a systematic search of new CSS, GPS and HFP sources with extended emission, as well as a more detailed study of some well-known of these sources. Here we present the key points of our search in the LOFAR fields and a more in-depth analysis on the source B2 0258+35, a CSS source surrounded by a pair of large, diffuse radio lobes.