  AXIS (An XMM-Newton International Survey) is a survey of 36 high Galactic
latitude XMM-Newton observations covering 4.8 deg2 and containing 1433
serendipitous X-ray sources detected with 5-sigma significance. We have studied
the X-ray source counts in four energy bands soft (0.5-2 keV), hard (2-10 keV),
XID (0.5-4.5 keV) and ultra-hard (4.5-7.5 keV). We have combined this survey
with shallower and deeper surveys. Our source counts results are compatible
with most previous samples in the soft, XID, ultra-hard and hard bands. The
fractions of the XRB resolved in the surveys used in this work are 87%, 85%,
60% and 25% in the soft, hard, XID and ultra-hard bands, respectively.
Extrapolation of our source counts to zero flux are not enough to saturate the
XRB intensity. Only galaxies and/or absorbed AGN may be able contribute the
remaining unresolved XRB intensity. Our results are compatible, within the
errors, with recent revisions of the XRB intensity in the soft and hard bands.
The maximum fractional contribution to the XRB comes from fluxes within about a
decade of the break in the source counts (~1e-14 cgs), reaching ~50% of the
total in the soft and hard bands. Using only AXIS sources, we have studied the
angular correlation in those bands using a novel robust technique. Angular
clustering (widely distributed over the sky and not confined to a few deep
fields) is detected at 99-99.9% significance in the soft and XID bands, with no
detection in the hard and ultra-hard band (probably due to the smaller number
of sources). We cannot confirm the detection of significantly stronger
clustering in the hard-spectrum hard sources. Medium depth surveys such as AXIS
are essential to determine the evolution of the X-ray emission in the Universe
below 10 keV.
