DOI

https://doi.org/10.48717/ej86-ae62

Project

EB074

Title

Zooming into the cores of restarting giant radio galaxies

Abstract

With their sizes larger than 0.7 Mpc, Giant Radio Galaxies (GRGs) are the largest individual objects in the Universe. To date, the reason why they reach such enormous extensions is still unclear. One of the proposed scenarios suggests that they are the result of multiple episodes of jet activity. Cross-correlating the INTEGRAL+Swift hard X-ray AGN population with radio catalogs (NVSS, FIRST, SUMSS), we found that 22% of the sources are GRG: a factor four higher than those selected from radio catalogues. Remarkably, all of the sample sources shows signs of restarting radio activity, either showing a young radio source in their core or from their morphology. With this proposal, we aim at studying at high resolution the cores of these GRGs, in terms of magnetic fields, brightness temperature, compactness, and orientation of the newborn jets, comparing that with a control sample of hard X-ray "quiet" GRGs (i.e. not detected in the mentioned INTEGRAL and Swift catalogues). This will allow us to probe any dependence of the radio phase on the hard X-ray luminosity, and thus on the accretion status, unveiling the properties of the cores able to form these unique radio structures.