The XMM–Newton/2dF survey – VIII. The extended X-ray sources

We present a sample of eight extended X-ray sources detected in the wide-field (～2.3 deg²), bright (2–10 ks) XMM–Newton /2dF survey, reaching a flux limit of  ～2 × 10^?14 erg s^?1 cm^?2  . Of these, seven are identified as secure X-ray clusters in the soft 0.3–2 keV band using a standard wavelet algorithm on either the PN or the MOS images. Spectroscopic or photometric redshifts are available for five clusters, spanning a range between 0.12 and 0.68. The X-ray spectral fittings show temperatures between 1 and 4.6 keV, characteristic of poor clusters and groups of galaxies. We derive for the first time the XMM–Newton cluster number count  log  N –log  S   distribution albeit with poor statistics. Both the  log  N –log  S   and the luminosity–temperature relation are in good agreement with previous ROSAT results.