Bent It Like FRs: Extended Radio AGN in the COSMOS Field and Their Large-Scale Environment

Abstract

A fascinating topic in radio astronomy is how to associate the complexity of observed radio structures with their environment in order to understand their interplay and the reason for the plethora of radio structures found in surveys. In this project, we explore the distortion of the radio structure of Fanaroff–Riley (FR)-type radio sources in the VLA-COSMOS Large Project at 3 GHz and relate it to their large-scale environment. We quantify the distortion by using the angle formed between the jets/lobes of two-sided FRs, namely bent angle (BA). Our sample includes 108 objects in the redshift range 0.08<z<3, which we cross-correlate to a wide range of large-scale environments (X-ray galaxy groups, density fields, and cosmic web probes) in the COSMOS field. The median BA of FRs in COSMOS at zmed∼0.9 is 167.5−37.5+11.5 degrees. We do not find significant correlations between BA and large-scale environments within COSMOS covering scales from a few kpc to several hundred Mpc, nor between BA and host properties. Finally, we compare our observational data to magnetohydrodynamical (MHD) adaptive-mesh simulations ENZO-MHD of two FR sources at z = 0.5 and at z = 1. Although the scatter in BA of the observed data is large, we see an agreement between observations and simulations in the bent angles of FRs, following a mild redshift evolution with BA. We conclude that, for a given object, the dominant mechanism affecting the radio structures of FRs could be the evolution of the ambient medium, where higher densities of the intergalactic medium at lower redshifts as probed by our study allow more space for jet interactions.

Life cycle of cosmic-ray electrons in the intracluster medium

“…Our model thus offers an unprecedented view of the largescale circulation and advection of fossil electrons on Megaparsec scales, in a regime scarcely affected by radiative cooling and other processes neglected in this work. The first applications of our simulations to the modelling of real radio sources were recently presented in Hodgson et al (2021), Vardoulaki et al (2021), and Brienza et al (2022).…”

New Window on the Radio Emission from Galaxies, Clusters and Cosmic Web—Conference Summary

“…They also compared the data to magneto-hydro-dynamical (MHD) adaptive-mesh simulations ENZO-MHD of two FR sources at z = 0.5 and z = 1. They found that the evolution of the ambient medium could be the dominant mechanism affecting the radio structures of FRs [25].…”

Simulating the enrichment of fossil radio electrons by multiple radio galaxies

“…Our series of recent works on this topic [27,28] aims at producing a complementary view on the above studies, by implementing the macroscopic effects of radio jets at a coarser spatial resolution, but also following the spatial and spectral energy evolution of the relativistic particles over billions of years after their injection, in fully cosmological MHD simulations. First applications of our simulations to real radio sources have recently been presented in [29], [30] and [20].…”