ChaMP Serendipitous Galaxy Cluster Survey

Barkhouse, Wayne A. ; Green, P.J. ; Vikhlinin, A. ; Kim, D.-W. ; Perley, D. ; Cameron, R. ; Silverman, J. ; Mossman, A. ; Burenin, R. ; Jannuzi, B.T. ; Kim, M. ; Smith, M.G. ; Smith, R.C. ; Tananbaum, H. ; Wilkes, B.J. ; /Harvard-Smithsonian Ctr. Astrophys. /UC, Berkeley, Astron. Dept. /SLAC /Garching, Max Planck Inst., MPE /Moscow, Space Res. Inst. /NOAO, Tucson /Cerro-Tololo InterAmerican Obs.

Stanford Linear Accelerator Center

关键词: X-Ray Sources Astrophysics,Astro;    Luminosity;    Galaxies;    Detection;    Contamination;   

DOI  :  10.2172/878722
RP-ID  :  SLAC-PUB-11798
RP-ID  :  AC02-76SF00515
RP-ID  :  878722

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来源: UNT Digital Library

【 摘 要 】

We present a survey of serendipitous extended X-ray sources and optical cluster candidates from the Chandra Multi-wavelength Project (ChaMP). Our main goal is to make an unbiased comparison of X-ray and optical cluster detection methods. In 130 archival Chandra pointings covering 13 square degrees, we use a wavelet decomposition technique to detect 55 extended sources, of which 6 are nearby single galaxies. Our X-ray cluster catalog reaches a typical flux limit of about {approx} 10{sup -14} erg s{sup -1} cm{sup -2}, with a median cluster core radius of 21''. For 56 of the 130 X-ray fields, we use the ChaMP's deep NOAO/4m MOSAIC g', r', and i' imaging to independently detect cluster candidates using a Voronoi tessellation and percolation (VTP) method. Red-sequence filtering decreases the galaxy fore/background contamination and provides photometric redshifts to z {approx} 0.7. From the overlapping 6.1 square degree X-ray/optical imaging, we find 115 optical clusters (of which 11% are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in the optical VTP catalog). The median redshift of the 13 X-ray/optical clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is L{sub X} = (2.65 {+-} 0.19) x 10{sup 43} ergs s{sup -1}. The clusters in our sample that are only detected in our optical data are poorer on average ({approx} 4{sigma}) than the X-ray/optically matched clusters, which may partially explain the difference in the detection fractions.