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 deg^2), bright (2-10 ksec) XMM-Newton/2dF survey, reaching a flux limit of ~2 X 10^{-14} erg/s/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.