  Wide area X-ray and far infrared surveys are a fundamental tool to
investigate the link between AGN growth and star formation, especially in the
low-redshift universe (z<1). The Herschel Terahertz Large Area survey (H-ATLAS)
has covered 550 deg^2 in five far-infrared and sub-mm bands, 16 deg^2 of which
have been presented in the Science Demonstration Phase (SDP) catalogue. Here we
introduce the XMM-Newton observations in H-ATLAS SDP area, covering 7.1 deg^2
with flux limits of 2e-15, 6e-15 and 9e-15 erg/s/cm^2 in the 0.5--2, 0.5--8 and
2--8 keV bands, respectively. We present the source detection and the
catalogue, which includes 1700, 1582 and 814 sources detected by Emldetect in
the 0.5--8, 0.5--2 and 2--8 keV bands, respectively; the number of unique
sources is 1816. We extract spectra and derive fluxes from power-law fits for
398 sources with more than 40 counts in the 0.5--8 keV band. We compare the
best-fit fluxes with the catalogue ones, obtained by assuming a common photon
index of Gamma=1.7; we find no bulk difference between the fluxes, and a
moderate dispersion of s=0.33 dex. Using wherever possible the fluxes from the
spectral fits, we derive the 2--10 keV LogN-LogS, which is consistent with a
Euclidean distribution. Finally, we release computer code for the tools
developed for this project.
