Abstract Details

Name: Sushant Dutta
Affiliation: Physical Research Laboratory, Ahmedabad
Conference ID: ASI2021_82
Title : Population of Remnant Radio Galaxies in Deep Radio Surveys
Authors and Co-Authors : Sushant Dutta (Physical Research Laboratory, Ahmedabad), Veeresh Singh (Physical Research Laboratory, Ahmedabad), C.H. Ishwara Chandra (National Centre for Radio Astrophysics - TIFR, Pune), Yogesh Wadadekar (National Centre for Radio Astrophysics - TIFR, Pune)
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : Remnant radio galaxies (RRGs) represent the last phase of radio galaxy life-cycle and is characterized by the “switch off” of AGN activity and the termination of jets supplying energetic plasma to the radio lobes. Despite the termination of jets, radio lobes can still be seen for a relatively short duration (105 – 106 years) before they disappear due to radiative losses. This makes RRGs short-lived and rare. Previous generation radio surveys have shown that the population of RRGs is even rarer than that predicted by evolutionary models. Recent deep low-frequency radio surveys are ideally suited to detect the population of RRGs because of the presence of steep spectral curvature in their integrated radio spectrum. In our work, we attempt to search for the population of RRGs using deep 325 MHz GMRT radio survey and auxiliary radio surveys. We find that the fraction of RRGs is much lower (~7%) than that predicted by radiative models, which in turn implies that the extended radio emission in lobes tends to fade quickly once AGN-jet activity switches off. In this presenation, I shall emphasize the need for deep multi-frequency radio surveys to constraint the fraction of RRGs and AGN duty-cycle.