The Ionized Absorber and Nuclear Environment of IRAS 13349+2438:
  Multi-wavelength insights from coordinated Chandra HETGS, HST STIS, HET, and
  Spitzer IRS
  We present results from a coordinated IR-to-X-ray spectral campaign of the
QSO IRAS 13349+2438. Optical spectra reveal extreme Eigenvector-1
characteristics, but the H-beta line width argues against a NLS1
classification; we refine z=0.10853 based on [O III]. We estimate a BH
mass=10^9 Msun using 2 independent methods (H-beta line width & SED fits).
Blue-shifted absorption (-950km/s & -75km/s) is seen for the 1st time in STIS
UV spectra from Ly-alpha, NV, & CIV. The higher velocity UV lines are
coincident with the lower-ionisation (xi~1.6) X-ray warm absorber lines. A
dusty multiple ionization absorber blueshifted by 700-900km/s is required to
fit the X-ray data. Theoretical models comparing different ionising SEDs reveal
that a UV-inclusive (i.e., the accretion disc) ionising continuum strongly
impacts conclusions for the thermodynamic stability of the warm absorber.
Specific to IRAS13349, an Xray-UV ionising SED favors a continuous distribution
of ionisation states in a smooth flow (this paper), versus discrete clouds in
pressure equilibrium (work by others where UV is omitted). Direct dust
detections are seen in both the IR: PAH emission at (7.7 & 11.3)micron which
may also be blended with forsterite, and (10 & 18)micron silicate emission, and
X-rays: iron dust with a dust-to-gas ratio > 90%. We develop a geometrical
model whereby the QSO nuclear region is viewed through the upper atmosphere of
an obscuring torus. This sight line is obscured by dust that blocks a direct
view of the UV/optical emission region but is largely transparent in X-rays
since the gas is ionised. In our model, 20% of the intrinsic UV/optical
continuum is scattered into our sight line by the far wall of an obscuring
torus. An additional 2.4% of the direct light, which likely dominates the UV
emission, is Thomson-scattered into our line-of-sight by another off-plane
component of highly ionized gas.
