期刊
ASTROPHYSICAL JOURNAL
卷 671, 期 2, 页码 1446-1455出版社
IOP PUBLISHING LTD
DOI: 10.1086/522879
关键词
cosmology : observations; galaxies : clusters : general; X-rays : galaxies : clusters
资金
- Science and Technology Facilities Council [PP/E001181/1] Funding Source: researchfish
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 +0.9 -0.5 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 x 10(9) yr, which is less than half of the age of the universe at this redshift given the current Lambda CDM 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 similar to 0:7R(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.
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