Type 1 low z AGN. I. Emission properties
  We analyze the emission properties of a new sample of 3,579 type 1 AGN,
selected from the SDSS DR7 based on the detection of broad H-alpha emission.
The sample extends over a broad H-alpha luminosity L_bHa of 10^40 - 10^44 erg
s^-1 and a broad H-alpha FWHM of 1,000 - 25,000 km s^-1, which covers the range
of black hole mass 10^6<M_BH/M_Sun<10^9.5 and luminosity in Eddington units
10^-3 < L/L_Edd < 1. We combine ROSAT, GALEX and 2MASS observations to form the
SED from 2.2 mic to 2 keV. We find the following: 1. The distribution of the
H-alpha FWHM values is independent of luminosity. 2. The observed mean
optical-UV SED is well matched by a fixed shape SED of luminous quasars, which
scales linearly with L_bHa, and a host galaxy contribution. 3. The host galaxy
r-band (fibre) luminosity function follows well the luminosity function of
inactive non-emission line galaxies (NEG), consistent with a fixed fraction of
~3% of NEG hosting an AGN, regardless of the host luminosity. 4. The hosts of
lower luminosity AGN have a mean z band luminosity and u-z colour which are
identical to NEG with the same redshift distribution. With increasing L_bHa the
AGN hosts become bluer and less luminous than NEG. The implied increasing star
formation rate with L_bHa is consistent with the relation for SDSS type 2 AGN
of similar bolometric luminosity. 5. The optical-UV SED of the more luminous
AGN shows a small dispersion, consistent with dust reddening of a blue SED, as
expected for thermal thin accretion disc emission. 6. There is a rather tight
relation of nuL_nu(2 keV) and L_bHa, which provides a useful probe for
unobscured (true) type 2 AGN. 7. The primary parameter which drives the X-ray
to UV emission ratio is the luminosity, rather than M_BH or L/L_Edd.
