S. Degrandi et al., A COMPLETE X-RAY SAMPLE OF CLUSTERS OF GALAXIES FROM THE ESO ALL-SOUTHERN SKY REDSHIFT SURVEY, Astrophysical letters & communications, 36(1-6), 1997, pp. 191-194
We describe the construction of an X-ray selected, flux limited sample
of 111 clusters of galaxies from the ESO Key Programme ''A Redshifts
Survey of ROSAT Clusters of Galaxies'' (ESO KP). This sample is extrac
ted from the ROSAT All-Sky Survey (PASS). In the first part of the pap
er we discuss a new method ''The Steepness Ratio Technique'' (SRT) whi
ch we have used to derive fluxes for our sources, The advantages of th
is method with respect to previous ones are many, For the first time i
n the analysis of extended RASS sources we: (1) use the correct RASS-P
SF, (2) derive a physical extension of the cluster candidates, and (3)
compute a count rate taking into account the survey PSF convolved Kin
g profile, The validity range of the method is tested using a control
sample of strong pointlike PASS sources. In the second part of the pap
er we discuss the selection criteria we have applied to the ESO KP sam
ple in order to maximize the degree of completeness of our flux limite
d sample. On the basis of a thorough analysis of the data we estimate
our sample to be complete at > 97% level. Finally, we derive a LogN-Lo
gS distribution with a limiting flux of similar to 3 x 10(-12) erg/s/c
m(2) in the 0.5-2.0 keV band.