X-ray selected Narrow-Line Seyfert 1 Galaxies
  We present and discuss the properties of a complete and well defined sample
of X-ray selected type 1 AGNs including 26 Narrow-Line Seyfert 1 and 129
Broad-Line Seyfert 1 galaxies derived from the XMM-Newton Bright Serendipitous
Survey (XBS). We study the differences between the two classes of AGNs for what
concerns the X-ray properties (the photon-index) and the main physical
parameters, like the Black-Hole mass and the Eddington ratio. We then consider
the two classes together and look for statistical correlations between observed
and physical parameters. We find a significant dependence of the photon-index
with the Eddington ratio and a weaker (possibly secondary) correlation between
the photon index and the Black-Hole Mass.
