Searching for X - ray luminous ‘ normal ’ galaxies in 2 dFGRS

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(fX /fO) < −2 for separating AGN from NGs. With XMM-Newton (Chandra) we covered an area of ∼ 8.2 (∼ 5.8) deg 2 down to a flux limit of ∼ 10 −15 (∼ 1.6 × 10 −15) erg cm −2 s −1 and found 18 (20) 2dFGRS galaxies. Using emission-line intensity ratios, we classified 6 2dFGRS spectra as star-forming, H ii nuclei, and 2 spectra as possible H ii 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 H ii and 3 absorption-line galaxies have log(fX /fO) > −2. We performed a similar search in two nearby-galaxy samples from the literature. All 44 galaxies in the Zezas (2001) sample have log(fX /fO) < −2 and LX < 10 42 erg s −1. In the Fabbiano et al. (1992) sample, out of a total of 170 'normal' galaxies, we found 16 galaxies with log(fX /fO) > −2, the majority of which are massive ellipticals. Three of these have LX > 10 42 erg s −1 .