1997/01/20 by C. A. Collins, D. J. Burke, A. K. Romer +2 · 6 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1086/310593
10 pages, AAS LaTeX macros v4.0, plus 5 EPSF figures, to appear in ApJL
arxiv created 1997/01/20 · openalex publication_date 1997/04/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We report on the first results from a redshift survey of a flux-limited sample of X-ray clusters selected serendipitously from the ROSAT PSPC data archive. We spectroscopically confirm 15 clusters in the range 0.3 < z < 0.7, to a flux limit of ≃3.9 × 10 -14 ergs s -1 cm -2 , over a survey area of 17.2 deg 2 . The surface density of clusters in our survey is 2.0 + 0.4 −0.3 deg -2 , in good agreement with the number density of cluster candidates detected using algorithms designed to search for very extended sources. The number of clusters detected between 0.3 < z < 0.7 is consistent with a prediction based on a simple extrapolation of the local X-ray cluster luminosity function, which indicates that over this redshift range no significant evolution in the cluster population has taken place. These results are in conflict with recent claims that the number density of X-ray clusters found in deep ROSAT PSPC pointings evolves rapidly beyond z = 0.3.