Hiding in Plain Sight - Recovering Clusters of Galaxies with the Strongest AGN in Their Cores

Abstract

A key challenge in understanding the feedback mechanism of AGN in Brightest Cluster Galaxies (BCGs) is the inherent rarity of catching an AGN during its strong outburst phase. This is exacerbated by the ambiguity of differentiating between AGN and clusters in X-ray observations. If there is evidence for an AGN then the X-ray emission is commonly assumed to be dominated by the AGN emission, introducing a selection effect against the detection of AGN in BCGs. In order to recover these 'missing' clusters, we systematically investigate the colour-magnitude relation around some ~3500 ROSAT All Sky Survey selected AGN, looking for signs of a cluster red sequence. Amongst our 22 candidate systems, we independently rediscover several confirmed systems, where a strong AGN resides in a central galaxy. We compare the X-ray luminosity to red sequence richness distribution of our AGN candidate systems with that of a similarly selected comparison sample of ~1000 confirmed clusters and identify seven 'best' candidates (all of which are BL Lac objects), where the X-ray flux is likely to be a comparable mix between cluster and AGN emission. We confirm that the colours of the red sequence are consistent with the redshift of the AGN, that the colours of the AGN host galaxy are consistent with AGN, and, by comparing their luminosities with those from our comparison clusters, confirm that the AGN hosts are consistent with BCGs.

Accepted for publication in MNRAS; 12 Pages + Appendix; 7 Figures and 4 Tables

References in corpus (17)

• Heating Hot Atmospheres with Active Galactic Nuclei
• Roma-BZCAT: A multifrequency catalogue of Blazars
• The 5th edition of the Roma-BZCAT. A short presentation
• A complete sample of twelve very X-ray luminous galaxy clusters at z>0.5
• An Infrared Survey of Brightest Cluster Galaxies. II: Why are Some Brightest Cluster Galaxies Forming Stars?
• Investigating AGN Heating in a Sample of Nearby Clusters
• An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores of Galaxy Clusters
• Searching for Cool Core Clusters at High redshift
• X-ray cavities in a sample of 83 SPT-selected clusters of galaxies: Tracing the evolution of AGN feedback in clusters of galaxies out to z=1.2
• Spectroscopic Confirmation of a Large AGN Population in Clusters of Galaxies
• A Large, Uniform Sample of X-ray Emitting AGN from the ROSAT All-Sky and Sloan Digital Sky Surveys: the Data Release 5 Sample
• A Non-thermal Study of the Brightest Cluster Galaxy NGC 1275 - The Gamma-Radio Connection Over Four Decades
• The effect of the quasar H1821+643 on the surrounding intracluster medium: revealing the underlying cooling flow
• Residual Cooling and Persistent Star Formation amid AGN Feedback in Abell 2597
• HST-COS Spectroscopy of the Cooling Flow in Abell 1795 - Evidence for Inefficient Star Formation in Condensing Intracluster Gas
• New active galactic nuclei detected in ROSAT All Sky Survey galaxies - The complete dataset
• Clustering environment of BL Lac object RGB 1745+398

Cited by in corpus (14)

• The eROSITA Final Equatorial-Depth Survey (eFEDS): Galaxy Clusters and Groups in Disguise
• Detecting clusters of galaxies and active galactic nuclei in an eROSITA all-sky survey digital twin
• Building a cluster: shocks, cavities, and cooling filaments in the group-group merger NGC 6338
• Dynamical masses of brightest cluster galaxies I: stellar velocity anisotropy and mass-to-light ratios
• The Clusters Hiding in Plain Sight (CHiPS) survey: Complete sample of extreme BCG clusters
• A New Physical Picture for AGNs Lacking Optical Emission Lines
• The variability of brightest cluster galaxies at high radio frequencies
• Dynamical masses of brightest cluster galaxies II: constraints on the stellar IMF
• The dust and cold gas content of local star forming galaxies
• A new look at the extragalactic Very High Energy sky: searching for TeV-emitting candidates among the X-ray bright, non-Fermi detected blazar population
• Evidence for AGN-Regulated Cooling in Clusters at $z\sim 1.4$: A Multi-Wavelength View of SPT-CL J0607-4448
• The First SRG/eROSITA All-Sky Survey. Characterization of clusters of galaxies misclassified in the eRASS1 point source catalog
• Extended Radio Structures and a Compact X-ray Cool-Core in the Cluster Source PKS 1353-341
• Constraining the synchrotron peak and estimating the VHE brightness of a sample of extreme high synchrotron peak blazars