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

Abstract

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 logN-logS distribution albeit with poor statistics. Both the logN-logS and the luminosity-temperature relation are in good agreement with previous ROSAT results.