X-RAY ANALYSIS OF ACTIVE GALACTIC NUCLEI IN CLUSTERS FROM THE DARK ENERGY SURVEY
Erica Bufanda1, Tesla Jeltema2, Devon Hollowood1, Eli Rykoff3, Eduardo Rozo3.
1University of California, Santa Cruz, Santa Cruz, CA, 2Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, Santa Cruz, CA, 3SLAC National Accelerator Laboratory, Menlo Park, CA.
We use Chandra X-ray images combined with optical information from the redMaPPer catalog of clusters of galaxies detected by the Dark Energy Survey (DES) to analyze the evolution of active galactic nuclei (AGN) and their host galaxies in large-scale structures. Recent research has shown that the presence of AGN in clusters is a function of redshift and cluster richness. Our purpose is to investigate these correlations and what this implies for the evolution of AGN in clusters. We accumulated a sample of 141 AGN in 659 clusters at 0.2 < z < 1 using an IDL-matching program that matches the optical positions of galaxies in clusters detected in early data from the DES redMaPPer cluster member catalog v. 6.2.12 with the X-ray positions of detected point sources in 93 different Chandra X-ray observations. We investigated the AGN fraction as a function of richness and redshift with a luminosity threshold of 1043 ergs/sec and selective richness and redshift cuts. We found that AGN in clusters of all richnesses increase by a factor of 8.8 from redshift 0.2 to 1. The high redshift AGN fraction is greater than the low redshift AGN fraction at 5σ. This is consistent with Martini et al’s, findings. In addition, the AGN fraction does not seem to have any significant dependence on cluster richness. Future work involves a recalculation of the AGN fraction and a reanalysis of our cluster AGN sample with the most current DES redMaPPer cluster catalog.