Bent radio AGN, with their classic “C” shaped morphology, are a unique class of radio AGNs. These radio sources are often used as signposts of a dense, gaseous medium, such as the intracluster medium (ICM). However, bent sources are found inside and outside cluster environments, raising the question of how environment impacts bent radio AGN morphology. We analyzed new LOw-Frequency Array Two-metre Sky Survey (LoTSS) Data Release II observations of 21 bent AGNs in clusters and 15 not in clusters from the high-z Clusters Occupied by Bent Radio AGN (COBRA) survey (0.35 < z < 2.35). We constrained the impact of environment on size, opening angle, lobe symmetry, and power. For the first time, we present spectral indices of a large sample of bent sources measured using LoTSS and Very Large Array Faint Images of the Radio Sky at Twenty-centimeters (VLA FIRST) observations. Although we find similar properties in terms of the asymmetry and size of the radio lobes, we see key differences regarding the opening angle and spectral index. We find that sources with narrower opening angles tend to be in cluster environments. While we measure similar spectral indices for bent AGNs in each, we find approximately 61.9% of cluster bent AGNs have flat cores (> -0.6) compared to 33.3% of non-clusters, indicating a key environmental signature and providing further evidence that these AGNs are in cluster environments. Beyond the core’s spectral index, bent AGNs inside and outside clusters are remarkably similar. Due to the similarity of the samples, it is possible that our sample of non-cluster bent AGNs may be more representative of extremely offset bent AGNs (> 1.4Mpc) or bent AGNs in weaker groups rather than the field.
BIO
Dr. Emmet Golden-Marx is a Shui Mu Fellow and postdoctoral researcher at Tsinghua University. He did his undergraduate studies at Brown University and earned his Ph.D. at Boston University in 2020, where he worked with Prof. Elizabeth Blanton studying bent radio AGNs in high-z galaxy clusters as part of the Clusters Occupied by Bent Radio AGN (COBRA) Survey. He is particularly interested in the interplay between galaxy clusters and radio AGNs and galaxy evolution in general. Emmet joined DoA in the fall of 2021 and works with Prof. Zheng Cai to study galaxy morphology in high-z protoclusters and radio AGNs in high-z clusters.
