The High-redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey: Investigating the Role of Environment on Bent Radio AGNs Using LOFAR

© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Bent radio active galactic nucleus (AGN) morphology depends on the density of the surrounding gas. However, bent sources are found inside and outside clusters, raising the question of how environment impacts bent AGN morphology. We analyze new LOw-Frequency Array the LOFAR Two-metre Sky Survey (LoTSS) Data Release II observations of 20 bent AGNs in clusters and 15 not in clusters from the high-z Clusters Occupied by Bent Radio AGN (COBRA) survey (0.35 1.2 Mpc) or bent AGNs in weaker groups rather than the field.Peer reviewe

Searching for C ii Emission from the First Sample of z ∼ 6 O i Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array

We report the first statistical analyses of [C ii ] and dust continuum observations in six strong O i absorber fields at the end of the reionization epoch obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combined with one [C ii ] emitter reported in Wu et al., we detect one O i -associated [C ii ] emitter in six fields. At redshifts of O i absorbers in nondetection fields, no emitters are brighter than our detection limit within impact parameters of 50 kpc and velocity offsets between ±200 km s ^−1 . The averaged [C ii ]-detection upper limit is 50 kpc) and having larger outflow velocities within ±600 km s ^−1 . If these detections are confirmed in the future, then the mechanism of pushing metals at larger distances with higher velocities needs to be further explored from the theoretical side

VLA resolves unexpected radio structures in the Perseus Cluster of galaxies

High Energy Astrophysic

Characterizing the intracluster light over the redshift range 0.2 < z < 0.8 in the DES-ACT overlap

We characterize the properties and evolution of bright central galaxies (BCGs) and the surrounding intracluster light (ICL) in galaxy clusters identified in the Dark Energy Survey and Atacama Cosmology Telescope Survey (DES-ACT) overlapping regions, covering the redshift range 0.20 14.4. We also measure the stellar mass–halo mass (SMHM) relation for the BCG+ICL system and find that the slope, β, which characterizes the dependence of M200m,SZ on the BCG+ICL stellar mass, increases with radius. The outskirts are more strongly correlated with the halo than the core, which supports that the BCG+ICL system follows a two-phase growth, where recent growth (z < 2) occurs beyond the BCG’s core. Additionally, we compare our observed SMHM relation results to the IllustrisTNG300-1 cosmological hydrodynamic simulations and find moderate qualitative agreement in the amount of diffuse light. However, the SMHM relation’s slope is steeper in TNG300-1 and the intrinsic scatter is lower, likely from the absence of projection effects in TNG300-1. Additionally, we find that the ICL exhibits a colour gradient such that the outskirts are bluer than the core. Moreover, for the lower halo mass clusters (log10(M200m,SZ/M☉) < 14.59), we detect a modest change in the colour gradient’s slope with lookback time, which combined with the absence of stellar mass growth may suggest that lower mass clusters have been involved in growth via tidal stripping more recently than their higher mass counterparts

Dark Energy Survey Year 6 Results: Intra-Cluster Light from Redshift 0.2 to 0.5

Using the full six years of imaging data from the Dark Energy Survey, we study the surface brightness profiles of galaxy cluster central galaxies and intra-cluster light. We apply a ``stacking'' method to over four thousand galaxy clusters identified by the redMaPPer cluster finding algorithm in the redshift range of 0.2 to 0.5. This yields high signal-to-noise radial profile measurements of the central galaxy and intra-cluster light out to 1 Mpc from the cluster center. Using redMaPPer richness as a cluster mass indicator, we find that the intra-cluster light brightness has a strong mass dependence throughout the 0.2 to 0.5 redshift range, and the dependence grows stronger at a larger radius. In terms of redshift evolution, we find some evidence that the central galaxy, as well as the diffuse light within the transition region between the cluster central galaxy and intra-cluster light within 80 kpc from the center, may be growing over time. At larger radii, more than 80 kpc away from the cluster center, we do not find evidence of additional redshift evolution beyond the cluster mass dependence, which is consistent with the findings from the IllustrisTNG hydrodynamic simulation. We speculate that the major driver of intra-cluster light growth, especially at large radii, is associated with cluster mass growth. Finally, we find that the color of the cluster central galaxy and intra-cluster light displays a radial gradient that becomes bluer at a larger radius, which is consistent with a stellar stripping and disruption origin of intra-cluster light as suggested by simulation studies.Comment: Submitted to MNRA