A comparison of hard X-ray photon indices and iron \ka emission lines in
  X-ray luminous narrow- and broad-line Seyfert 1 galaxies
  We use publicly available XMM-Newton data to systematically compare the hard
X-ray photon indices, $\Gamma_{\rm 2-10\ keV}$ and the iron K$\alpha$ emission
lines of narrow-line (NL) and broad-line Seyfert 1 (BLS1) galaxies. We compile
a flux-limited ($f_{\rm 2-10\ keV} \geq 1 \times 10^{-12}$ erg s$^{-1}$
cm$^{-2}$) sample including 114 radio-quiet objects, with the 2-10 keV
luminosity ranging from 10$^{41}$ to 10$^{45}$ erg s$^{-1}$. Our main results
are: 1) NLS1s and BLS1s show similar luminosity distributions; 2) The weighted
mean of $\Gamma_{\rm 2-10\ keV}$ of NLS1s, BLS1s and the total sample is
$2.04\pm0.04$, $1.74\pm0.02$, $1.84\pm0.02$, respectively; a significant
anti-correlation between \ga and FWHMH$\beta$ suggests that $\Gamma_{\rm 2-10\
keV} > 2.0$ may be taken to indicate X-ray luminous NLS1 type; 3) The 6.4 keV
narrow iron K$\alpha$ lines from NLS1s are generally weaker than that from
BLS1s; this would indicate a smaller covering factor of the dusty tori in
NLS1s, if the line emission originates from the inner boundary region of the
dusty torus in an AGN; 4) all the broadened iron K$\alpha$ lines with intrinsic
width $\sigma>0.5$ keV correspond to FWHM\hb $\leq 4000 ~\kms$.
