The Hellas2xmm Survey: I. the X-ray Data and the Log(n)-log(s)

We present the first results from an XMM-Newton serendipitous medium-deep survey, which covers nearly three square degrees. We detect a total of 1022, 495 and 100 sources, down to minimum fluxes of about 5.9× 10−16, 2.8× 10−15 and 6.2× 10−15 erg cm−2 s−1, in the 0.5-2, 2-10 and 4.5-10 keV band, respectively. In the soft band this is one of the largest samples available to date and surely the largest in the 2-10 keV band at our limiting X-ray flux. The measured Log(N)-Log(S) are found to be in good agreement with previous determinations. In the 0.5-2 keV band we detect a break at fluxes around 5× 10−15 erg cm−2 s−1. In the harder bands, we fill in the gap at intermediate fluxes between deeper Chandra and XMM-Newton observations and shallower BeppoSAX and ASCA surveys. Subject headings: galaxies: active — X-rays: diffuse background — X-rays: galaxies