Searching for X-ray luminous normal galaxies in 2dFGRS

Aims. We cross-correlated the Chandra XASSIST and XMM-Newton Serendipitous Source Catalogues with the 2 degree Field Galaxy Redshift Survey (2dFGRS) database. Our aim was to identify the most X-ray luminous (LX > 10(42) erg s(-1)) examples of galaxies in the local Universe whose X-ray emission is dominated by stellar processes rather than AGN activity (normal galaxies), as well as to test the empirical criterion log(f(X)/f(O)) < - 2 for separating AGN from NGs. We also performed a similar search in two nearby-galaxy samples from the literature. Methods. With XMM-Newton (Chandra) we covered an area of similar to 8.2 (similar to 5.8) deg(2) down to a flux limit of similar to 10(-15) (similar to 1.6 x 10(-15)) erg cm(-2) s-1. We classified 2dFGRS spectra using emission-line intensity ratios. Results. We found 18 (20) 2dFGRS galaxies with XMM-Newton (Chandra), which constitute our XMM-Newton-2dFGRS (Chandra-2dFGRS) correlation sample. We classified 6 2dFGRS spectra as star-forming, HII nuclei, and 2 spectra as possible HII nuclei. The rest of the objects are absorption-line galaxies and AGN, including 3 possible LINERs. No luminous normal galaxies have been found, but out of 19 normal galaxies in this sample, 5 HII and 3 absorption-line galaxies have log(f(X)/f(O)) > - 2. Furthermore, all 44 galaxies in the first literature sample have log(f(X)/f(O)) < - 2 and L-X < 10(42) erg s(-1). In the second literature sample, out of a total of 170 normal galaxies, we found 16 galaxies with log(f(X)/f(O)) < - 2, the majority of which are massive ellipticals. Three of these have LX > 10(42) erg s(-1). Conclusions. We found no luminous normal galaxies in our XMM-Newton-2dFGRS and Chandra-2dFGRS correlation samples. We found three such galaxies in the second literature sample. Considering all samples, we find that the log(f(X)/f(O)) < - 2 criterion seems to select primarily against the brightest, massive ellipticals.