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The ROSAT Brightest Cluster Sample – IV. The extended sample |
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| Authors: | H Ebeling A C Edge S W Allen C S Crawford A C Fabian J P Huchra |
| Institution: | Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr., D-85740 Garching, Germany;Institute of Astronomy, Madingley Road, Cambridge CB3 0HA;Institute for Astronomy, 2680 Woodlawn Drive Honolulu, HI 96822, USA;Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA |
| Abstract: | We present a low-flux extension of the X-ray-selected ROSAT Brightest Cluster Sample (BCS) published in Paper I of this series. Like the original BCS and employing an identical selection procedure, the BCS extension is compiled from ROSAT All-Sky Survey (RASS) data in the northern hemisphere ( δ ≥0°) and at high Galactic latitudes (| b |≥20°). It comprises 99 X-ray-selected clusters of galaxies with measured redshifts z ≤0.3 (as well as eight more at z >0.3) and total fluxes between 2.8×10 The nominal completeness of the combined sample (defined with respect to a power-law fit to the bright end of the BCS log N –log S distribution) is relatively low at 75 per cent (compared with 90 per cent for the high-flux sample of Paper I). However, just as for the original BCS, this incompleteness can be accurately quantified, and thus statistically corrected for, as a function of X-ray luminosity and redshift. In addition to its importance for improved statistical studies of the properties of clusters in the local Universe, the low-flux extension of the BCS is also intended to serve as a finding list for X-ray-bright clusters in the northern hemisphere which we hope will prove useful in the preparation of cluster observations with the next generation of X-ray telescopes such as Chandra and XMM-Newton . An electronic version of the eBCS can be obtained from the following URL: http://www.ifa.hawaii.edu/~ebeling/clusters/BCS.html. |
| Keywords: | surveys galaxies: clusters: general X-rays: galaxies |