2007/08/27 by A. K. Hicks, Amalia K. Hicks, Erica Ellingson +12
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #RADIUS #Redshift #Stellar, planetary, and galactic studies #Surface brightness #Velocity dispersion #astro-ph
paper · pdf · doi:10.1086/522879
32 pages, 9 figures. Accepted for publication in The Astrophysical Journal
arxiv created 2007/08/27 · openalex publication_date 2007/12/20 · arxiv updated 2009/12/01 · openalex created_date 2022/10/07 · openalex updated_date 2026/08/05
We present the results of two (101 ks total) Chandra observations of the z = 0.778 optically selected lensing cluster RCS 022434-0002.5, along with weak lensing and dynamical analyses of this object. An X-ray spectrum extracted within R 2500 (362 h 70 −1 kpc) results in an integrated cluster temperature of 5.1 −0.5 +0.9 keV. The surface brightness profile of RCS 022434-0002.5 indicates the presence of a slight excess of emission in the core. A hardness ratio image of this object reveals that this central emission is primarily produced by soft X-rays. Further investigation yields a cluster cooling time of 3.3 × 10 9 yr, which is less than half of the age of the universe at this redshift given the current ΛCDM cosmology. A weak lensing analysis is performed using HST images, and our weak lensing mass estimate is found to be in good agreement with the X-ray-determined mass of the cluster. Spectroscopic analysis reveals that RCS 022434-0002.5 has a velocity dispersion of 900 ± 180 km s −1 , consistent with its X-ray temperature. The core gas mass fraction of RCS 022434-0002.5 is, however, found to be 3 times lower than expected universal values. The radial distribution of X-ray point sources within R 200 of this cluster peaks at ~0.7 R 200 , possibly indicating that the cluster potential is influencing AGN activity at that radius. Correlations between X-ray and radio (VLA) point-source positions are also examined.