The XMM-Newton Wide Angle Survey (XWAS)
  This programme is aimed at obtaining one of the largest X-ray selected
samples of identified active galactic nuclei to date in order to characterise
such a population at intermediate fluxes, where most of the Universe's
accretion power originates. We present the XMM-Newton Wide Angle Survey (XWAS),
a new catalogue of almost a thousand X-ray sources spectroscopically identified
through optical observations. A sample of X-ray sources detected in 68
XMM-Newton pointed observations was selected for optical multi-fibre
spectroscopy. Optical counterparts and corresponding photometry of the X-ray
sources were obtained from the SuperCOSMOS Sky Survey. Candidates for
spectroscopy were initially selected with magnitudes down to R~21, with
preference for X-ray sources having a flux F(0.5-4.5 keV) >10^-14 erg s^-1
cm^-2. Optical spectroscopic observations performed at the Anglo Australian
Telescope Two Degree Field were analysed, and the derived spectra were
classified based on optical emission lines. We have identified through optical
spectroscopy 940 X-ray sources over ~11.8 deg^2 of the sky. Source populations
in our sample can be summarised as 65% broad line active galactic nuclei
(BLAGN), 16% narrow emission line galaxies (NELGs), 6% absorption line galaxies
(ALGs) and 13% stars. An active nucleus is likely to be present also in the
large majority of the X-ray sources spectroscopically classified as NELGs or
ALGs. Sources lie in high-galactic latitude (|b| > 20 deg) XMM-Newton fields
mainly in the southern hemisphere. Due to the large parameter space in redshift
(0 < z < 4.25) and flux (10^-15 < F(0.5-4.5 keV) < 10^-12 erg s^-1 cm^-2)
covered by the XWAS this work provides an excellent resource to further study
subsamples and particular cases. The overall properties of the extragalactic
objects are presented in this paper.
